From afaef01c001537fa97a25092d7f54d764dc7d8c1 Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Fri, 17 Aug 2018 01:16:58 +0300 Subject: x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls The STACKLEAK feature (initially developed by PaX Team) has the following benefits: 1. Reduces the information that can be revealed through kernel stack leak bugs. The idea of erasing the thread stack at the end of syscalls is similar to CONFIG_PAGE_POISONING and memzero_explicit() in kernel crypto, which all comply with FDP_RIP.2 (Full Residual Information Protection) of the Common Criteria standard. 2. Blocks some uninitialized stack variable attacks (e.g. CVE-2017-17712, CVE-2010-2963). That kind of bugs should be killed by improving C compilers in future, which might take a long time. This commit introduces the code filling the used part of the kernel stack with a poison value before returning to userspace. Full STACKLEAK feature also contains the gcc plugin which comes in a separate commit. The STACKLEAK feature is ported from grsecurity/PaX. More information at: https://grsecurity.net/ https://pax.grsecurity.net/ This code is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on our understanding of the code. Changes or omissions from the original code are ours and don't reflect the original grsecurity/PaX code. Performance impact: Hardware: Intel Core i7-4770, 16 GB RAM Test #1: building the Linux kernel on a single core 0.91% slowdown Test #2: hackbench -s 4096 -l 2000 -g 15 -f 25 -P 4.2% slowdown So the STACKLEAK description in Kconfig includes: "The tradeoff is the performance impact: on a single CPU system kernel compilation sees a 1% slowdown, other systems and workloads may vary and you are advised to test this feature on your expected workload before deploying it". Signed-off-by: Alexander Popov Acked-by: Thomas Gleixner Reviewed-by: Dave Hansen Acked-by: Ingo Molnar Signed-off-by: Kees Cook --- scripts/gcc-plugins/Kconfig | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'scripts') diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index cb0c889e13aa..977b84e69787 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -139,4 +139,23 @@ config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE in structures. This reduces the performance hit of RANDSTRUCT at the cost of weakened randomization. +config GCC_PLUGIN_STACKLEAK + bool "Erase the kernel stack before returning from syscalls" + depends on GCC_PLUGINS + depends on HAVE_ARCH_STACKLEAK + help + This option makes the kernel erase the kernel stack before + returning from system calls. That reduces the information which + kernel stack leak bugs can reveal and blocks some uninitialized + stack variable attacks. + + The tradeoff is the performance impact: on a single CPU system kernel + compilation sees a 1% slowdown, other systems and workloads may vary + and you are advised to test this feature on your expected workload + before deploying it. + + This plugin was ported from grsecurity/PaX. More information at: + * https://grsecurity.net/ + * https://pax.grsecurity.net/ + endif -- cgit v1.3-6-gb490 From 10e9ae9fabaf96c8e5227c1cd4827d58b3aa406d Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Fri, 17 Aug 2018 01:16:59 +0300 Subject: gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack The STACKLEAK feature erases the kernel stack before returning from syscalls. That reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks. This commit introduces the STACKLEAK gcc plugin. It is needed for tracking the lowest border of the kernel stack, which is important for the code erasing the used part of the kernel stack at the end of syscalls (comes in a separate commit). The STACKLEAK feature is ported from grsecurity/PaX. More information at: https://grsecurity.net/ https://pax.grsecurity.net/ This code is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on our understanding of the code. Changes or omissions from the original code are ours and don't reflect the original grsecurity/PaX code. Signed-off-by: Alexander Popov Tested-by: Laura Abbott Signed-off-by: Kees Cook --- kernel/stackleak.c | 28 +++ scripts/Makefile.gcc-plugins | 10 + scripts/gcc-plugins/Kconfig | 12 + scripts/gcc-plugins/stackleak_plugin.c | 427 +++++++++++++++++++++++++++++++++ 4 files changed, 477 insertions(+) create mode 100644 scripts/gcc-plugins/stackleak_plugin.c (limited to 'scripts') diff --git a/kernel/stackleak.c b/kernel/stackleak.c index deba0d8992f9..628485db37ba 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -60,3 +60,31 @@ asmlinkage void stackleak_erase(void) current->lowest_stack = current_top_of_stack() - THREAD_SIZE/64; } +void __used stackleak_track_stack(void) +{ + /* + * N.B. stackleak_erase() fills the kernel stack with the poison value, + * which has the register width. That code assumes that the value + * of 'lowest_stack' is aligned on the register width boundary. + * + * That is true for x86 and x86_64 because of the kernel stack + * alignment on these platforms (for details, see 'cc_stack_align' in + * arch/x86/Makefile). Take care of that when you port STACKLEAK to + * new platforms. + */ + unsigned long sp = (unsigned long)&sp; + + /* + * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than + * STACKLEAK_SEARCH_DEPTH makes the poison search in + * stackleak_erase() unreliable. Let's prevent that. + */ + BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH); + + if (sp < current->lowest_stack && + sp >= (unsigned long)task_stack_page(current) + + sizeof(unsigned long)) { + current->lowest_stack = sp; + } +} +EXPORT_SYMBOL(stackleak_track_stack); diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 0a482f341576..46c5c6809806 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -26,6 +26,16 @@ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) \ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE) \ += -fplugin-arg-randomize_layout_plugin-performance-mode +gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so +gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ + += -DSTACKLEAK_PLUGIN +gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ + += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) +ifdef CONFIG_GCC_PLUGIN_STACKLEAK + DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable +endif +export DISABLE_STACKLEAK_PLUGIN + # All the plugin CFLAGS are collected here in case a build target needs to # filter them out of the KBUILD_CFLAGS. GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index 977b84e69787..c65fdd823591 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -158,4 +158,16 @@ config GCC_PLUGIN_STACKLEAK * https://grsecurity.net/ * https://pax.grsecurity.net/ +config STACKLEAK_TRACK_MIN_SIZE + int "Minimum stack frame size of functions tracked by STACKLEAK" + default 100 + range 0 4096 + depends on GCC_PLUGIN_STACKLEAK + help + The STACKLEAK gcc plugin instruments the kernel code for tracking + the lowest border of the kernel stack (and for some other purposes). + It inserts the stackleak_track_stack() call for the functions with + a stack frame size greater than or equal to this parameter. + If unsure, leave the default value 100. + endif diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c new file mode 100644 index 000000000000..2f48da98b5d4 --- /dev/null +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -0,0 +1,427 @@ +/* + * Copyright 2011-2017 by the PaX Team + * Modified by Alexander Popov + * Licensed under the GPL v2 + * + * Note: the choice of the license means that the compilation process is + * NOT 'eligible' as defined by gcc's library exception to the GPL v3, + * but for the kernel it doesn't matter since it doesn't link against + * any of the gcc libraries + * + * This gcc plugin is needed for tracking the lowest border of the kernel stack. + * It instruments the kernel code inserting stackleak_track_stack() calls: + * - after alloca(); + * - for the functions with a stack frame size greater than or equal + * to the "track-min-size" plugin parameter. + * + * This plugin is ported from grsecurity/PaX. For more information see: + * https://grsecurity.net/ + * https://pax.grsecurity.net/ + * + * Debugging: + * - use fprintf() to stderr, debug_generic_expr(), debug_gimple_stmt(), + * print_rtl() and print_simple_rtl(); + * - add "-fdump-tree-all -fdump-rtl-all" to the plugin CFLAGS in + * Makefile.gcc-plugins to see the verbose dumps of the gcc passes; + * - use gcc -E to understand the preprocessing shenanigans; + * - use gcc with enabled CFG/GIMPLE/SSA verification (--enable-checking). + */ + +#include "gcc-common.h" + +__visible int plugin_is_GPL_compatible; + +static int track_frame_size = -1; +static const char track_function[] = "stackleak_track_stack"; + +/* + * Mark these global variables (roots) for gcc garbage collector since + * they point to the garbage-collected memory. + */ +static GTY(()) tree track_function_decl; + +static struct plugin_info stackleak_plugin_info = { + .version = "201707101337", + .help = "track-min-size=nn\ttrack stack for functions with a stack frame size >= nn bytes\n" + "disable\t\tdo not activate the plugin\n" +}; + +static void stackleak_add_track_stack(gimple_stmt_iterator *gsi, bool after) +{ + gimple stmt; + gcall *stackleak_track_stack; + cgraph_node_ptr node; + int frequency; + basic_block bb; + + /* Insert call to void stackleak_track_stack(void) */ + stmt = gimple_build_call(track_function_decl, 0); + stackleak_track_stack = as_a_gcall(stmt); + if (after) { + gsi_insert_after(gsi, stackleak_track_stack, + GSI_CONTINUE_LINKING); + } else { + gsi_insert_before(gsi, stackleak_track_stack, GSI_SAME_STMT); + } + + /* Update the cgraph */ + bb = gimple_bb(stackleak_track_stack); + node = cgraph_get_create_node(track_function_decl); + gcc_assert(node); + frequency = compute_call_stmt_bb_frequency(current_function_decl, bb); + cgraph_create_edge(cgraph_get_node(current_function_decl), node, + stackleak_track_stack, bb->count, frequency); +} + +static bool is_alloca(gimple stmt) +{ + if (gimple_call_builtin_p(stmt, BUILT_IN_ALLOCA)) + return true; + +#if BUILDING_GCC_VERSION >= 4007 + if (gimple_call_builtin_p(stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) + return true; +#endif + + return false; +} + +/* + * Work with the GIMPLE representation of the code. Insert the + * stackleak_track_stack() call after alloca() and into the beginning + * of the function if it is not instrumented. + */ +static unsigned int stackleak_instrument_execute(void) +{ + basic_block bb, entry_bb; + bool prologue_instrumented = false, is_leaf = true; + gimple_stmt_iterator gsi; + + /* + * ENTRY_BLOCK_PTR is a basic block which represents possible entry + * point of a function. This block does not contain any code and + * has a CFG edge to its successor. + */ + gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + entry_bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)); + + /* + * Loop through the GIMPLE statements in each of cfun basic blocks. + * cfun is a global variable which represents the function that is + * currently processed. + */ + FOR_EACH_BB_FN(bb, cfun) { + for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) { + gimple stmt; + + stmt = gsi_stmt(gsi); + + /* Leaf function is a function which makes no calls */ + if (is_gimple_call(stmt)) + is_leaf = false; + + if (!is_alloca(stmt)) + continue; + + /* Insert stackleak_track_stack() call after alloca() */ + stackleak_add_track_stack(&gsi, true); + if (bb == entry_bb) + prologue_instrumented = true; + } + } + + if (prologue_instrumented) + return 0; + + /* + * Special cases to skip the instrumentation. + * + * Taking the address of static inline functions materializes them, + * but we mustn't instrument some of them as the resulting stack + * alignment required by the function call ABI will break other + * assumptions regarding the expected (but not otherwise enforced) + * register clobbering ABI. + * + * Case in point: native_save_fl on amd64 when optimized for size + * clobbers rdx if it were instrumented here. + * + * TODO: any more special cases? + */ + if (is_leaf && + !TREE_PUBLIC(current_function_decl) && + DECL_DECLARED_INLINE_P(current_function_decl)) { + return 0; + } + + if (is_leaf && + !strncmp(IDENTIFIER_POINTER(DECL_NAME(current_function_decl)), + "_paravirt_", 10)) { + return 0; + } + + /* Insert stackleak_track_stack() call at the function beginning */ + bb = entry_bb; + if (!single_pred_p(bb)) { + /* gcc_assert(bb_loop_depth(bb) || + (bb->flags & BB_IRREDUCIBLE_LOOP)); */ + split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)); + } + gsi = gsi_after_labels(bb); + stackleak_add_track_stack(&gsi, false); + + return 0; +} + +static bool large_stack_frame(void) +{ +#if BUILDING_GCC_VERSION >= 8000 + return maybe_ge(get_frame_size(), track_frame_size); +#else + return (get_frame_size() >= track_frame_size); +#endif +} + +/* + * Work with the RTL representation of the code. + * Remove the unneeded stackleak_track_stack() calls from the functions + * which don't call alloca() and don't have a large enough stack frame size. + */ +static unsigned int stackleak_cleanup_execute(void) +{ + rtx_insn *insn, *next; + + if (cfun->calls_alloca) + return 0; + + if (large_stack_frame()) + return 0; + + /* + * Find stackleak_track_stack() calls. Loop through the chain of insns, + * which is an RTL representation of the code for a function. + * + * The example of a matching insn: + * (call_insn 8 4 10 2 (call (mem (symbol_ref ("stackleak_track_stack") + * [flags 0x41] ) + * [0 stackleak_track_stack S1 A8]) (0)) 675 {*call} (expr_list + * (symbol_ref ("stackleak_track_stack") [flags 0x41] ) (expr_list (0) (nil))) (nil)) + */ + for (insn = get_insns(); insn; insn = next) { + rtx body; + + next = NEXT_INSN(insn); + + /* Check the expression code of the insn */ + if (!CALL_P(insn)) + continue; + + /* + * Check the expression code of the insn body, which is an RTL + * Expression (RTX) describing the side effect performed by + * that insn. + */ + body = PATTERN(insn); + + if (GET_CODE(body) == PARALLEL) + body = XVECEXP(body, 0, 0); + + if (GET_CODE(body) != CALL) + continue; + + /* + * Check the first operand of the call expression. It should + * be a mem RTX describing the needed subroutine with a + * symbol_ref RTX. + */ + body = XEXP(body, 0); + if (GET_CODE(body) != MEM) + continue; + + body = XEXP(body, 0); + if (GET_CODE(body) != SYMBOL_REF) + continue; + + if (SYMBOL_REF_DECL(body) != track_function_decl) + continue; + + /* Delete the stackleak_track_stack() call */ + delete_insn_and_edges(insn); +#if BUILDING_GCC_VERSION >= 4007 && BUILDING_GCC_VERSION < 8000 + if (GET_CODE(next) == NOTE && + NOTE_KIND(next) == NOTE_INSN_CALL_ARG_LOCATION) { + insn = next; + next = NEXT_INSN(insn); + delete_insn_and_edges(insn); + } +#endif + } + + return 0; +} + +static bool stackleak_gate(void) +{ + tree section; + + section = lookup_attribute("section", + DECL_ATTRIBUTES(current_function_decl)); + if (section && TREE_VALUE(section)) { + section = TREE_VALUE(TREE_VALUE(section)); + + if (!strncmp(TREE_STRING_POINTER(section), ".init.text", 10)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".devinit.text", 13)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".cpuinit.text", 13)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".meminit.text", 13)) + return false; + } + + return track_frame_size >= 0; +} + +/* Build the function declaration for stackleak_track_stack() */ +static void stackleak_start_unit(void *gcc_data __unused, + void *user_data __unused) +{ + tree fntype; + + /* void stackleak_track_stack(void) */ + fntype = build_function_type_list(void_type_node, NULL_TREE); + track_function_decl = build_fn_decl(track_function, fntype); + DECL_ASSEMBLER_NAME(track_function_decl); /* for LTO */ + TREE_PUBLIC(track_function_decl) = 1; + TREE_USED(track_function_decl) = 1; + DECL_EXTERNAL(track_function_decl) = 1; + DECL_ARTIFICIAL(track_function_decl) = 1; + DECL_PRESERVE_P(track_function_decl) = 1; +} + +/* + * Pass gate function is a predicate function that gets executed before the + * corresponding pass. If the return value is 'true' the pass gets executed, + * otherwise, it is skipped. + */ +static bool stackleak_instrument_gate(void) +{ + return stackleak_gate(); +} + +#define PASS_NAME stackleak_instrument +#define PROPERTIES_REQUIRED PROP_gimple_leh | PROP_cfg +#define TODO_FLAGS_START TODO_verify_ssa | TODO_verify_flow | TODO_verify_stmts +#define TODO_FLAGS_FINISH TODO_verify_ssa | TODO_verify_stmts | TODO_dump_func \ + | TODO_update_ssa | TODO_rebuild_cgraph_edges +#include "gcc-generate-gimple-pass.h" + +static bool stackleak_cleanup_gate(void) +{ + return stackleak_gate(); +} + +#define PASS_NAME stackleak_cleanup +#define TODO_FLAGS_FINISH TODO_dump_func +#include "gcc-generate-rtl-pass.h" + +/* + * Every gcc plugin exports a plugin_init() function that is called right + * after the plugin is loaded. This function is responsible for registering + * the plugin callbacks and doing other required initialization. + */ +__visible int plugin_init(struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + const int argc = plugin_info->argc; + const struct plugin_argument * const argv = plugin_info->argv; + int i = 0; + + /* Extra GGC root tables describing our GTY-ed data */ + static const struct ggc_root_tab gt_ggc_r_gt_stackleak[] = { + { + .base = &track_function_decl, + .nelt = 1, + .stride = sizeof(track_function_decl), + .cb = >_ggc_mx_tree_node, + .pchw = >_pch_nx_tree_node + }, + LAST_GGC_ROOT_TAB + }; + + /* + * The stackleak_instrument pass should be executed before the + * "optimized" pass, which is the control flow graph cleanup that is + * performed just before expanding gcc trees to the RTL. In former + * versions of the plugin this new pass was inserted before the + * "tree_profile" pass, which is currently called "profile". + */ + PASS_INFO(stackleak_instrument, "optimized", 1, + PASS_POS_INSERT_BEFORE); + + /* + * The stackleak_cleanup pass should be executed after the + * "reload" pass, when the stack frame size is final. + */ + PASS_INFO(stackleak_cleanup, "reload", 1, PASS_POS_INSERT_AFTER); + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + /* Parse the plugin arguments */ + for (i = 0; i < argc; i++) { + if (!strcmp(argv[i].key, "disable")) + return 0; + + if (!strcmp(argv[i].key, "track-min-size")) { + if (!argv[i].value) { + error(G_("no value supplied for option '-fplugin-arg-%s-%s'"), + plugin_name, argv[i].key); + return 1; + } + + track_frame_size = atoi(argv[i].value); + if (track_frame_size < 0) { + error(G_("invalid option argument '-fplugin-arg-%s-%s=%s'"), + plugin_name, argv[i].key, argv[i].value); + return 1; + } + } else { + error(G_("unknown option '-fplugin-arg-%s-%s'"), + plugin_name, argv[i].key); + return 1; + } + } + + /* Give the information about the plugin */ + register_callback(plugin_name, PLUGIN_INFO, NULL, + &stackleak_plugin_info); + + /* Register to be called before processing a translation unit */ + register_callback(plugin_name, PLUGIN_START_UNIT, + &stackleak_start_unit, NULL); + + /* Register an extra GCC garbage collector (GGC) root table */ + register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, + (void *)>_ggc_r_gt_stackleak); + + /* + * Hook into the Pass Manager to register new gcc passes. + * + * The stack frame size info is available only at the last RTL pass, + * when it's too late to insert complex code like a function call. + * So we register two gcc passes to instrument every function at first + * and remove the unneeded instrumentation later. + */ + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, + &stackleak_instrument_pass_info); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, + &stackleak_cleanup_pass_info); + + return 0; +} -- cgit v1.3-6-gb490 From c8d126275a5fa59394fe17109bdb9812fed296b8 Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Fri, 17 Aug 2018 01:17:01 +0300 Subject: fs/proc: Show STACKLEAK metrics in the /proc file system Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about tasks via the /proc file system. In particular, /proc//stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it can be useful for estimating the STACKLEAK performance impact for your workloads. Suggested-by: Ingo Molnar Signed-off-by: Alexander Popov Tested-by: Laura Abbott Signed-off-by: Kees Cook --- fs/proc/base.c | 18 ++++++++++++++++++ include/linux/sched.h | 1 + include/linux/stackleak.h | 3 +++ kernel/stackleak.c | 4 ++++ scripts/gcc-plugins/Kconfig | 12 ++++++++++++ 5 files changed, 38 insertions(+) (limited to 'scripts') diff --git a/fs/proc/base.c b/fs/proc/base.c index ccf86f16d9f0..2a238d68610e 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2891,6 +2891,21 @@ static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns, } #endif /* CONFIG_LIVEPATCH */ +#ifdef CONFIG_STACKLEAK_METRICS +static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *task) +{ + unsigned long prev_depth = THREAD_SIZE - + (task->prev_lowest_stack & (THREAD_SIZE - 1)); + unsigned long depth = THREAD_SIZE - + (task->lowest_stack & (THREAD_SIZE - 1)); + + seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n", + prev_depth, depth); + return 0; +} +#endif /* CONFIG_STACKLEAK_METRICS */ + /* * Thread groups */ @@ -2992,6 +3007,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_LIVEPATCH ONE("patch_state", S_IRUSR, proc_pid_patch_state), #endif +#ifdef CONFIG_STACKLEAK_METRICS + ONE("stack_depth", S_IRUGO, proc_stack_depth), +#endif }; static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx) diff --git a/include/linux/sched.h b/include/linux/sched.h index c1a23acd24e7..ae9d10e14b82 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1194,6 +1194,7 @@ struct task_struct { #ifdef CONFIG_GCC_PLUGIN_STACKLEAK unsigned long lowest_stack; + unsigned long prev_lowest_stack; #endif /* diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index 628c2b947b89..b911b973d328 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -18,6 +18,9 @@ static inline void stackleak_task_init(struct task_struct *t) { t->lowest_stack = (unsigned long)end_of_stack(t) + sizeof(unsigned long); +# ifdef CONFIG_STACKLEAK_METRICS + t->prev_lowest_stack = t->lowest_stack; +# endif } #else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ static inline void stackleak_task_init(struct task_struct *t) { } diff --git a/kernel/stackleak.c b/kernel/stackleak.c index 628485db37ba..f66239572c89 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -41,6 +41,10 @@ asmlinkage void stackleak_erase(void) if (kstack_ptr == boundary) kstack_ptr += sizeof(unsigned long); +#ifdef CONFIG_STACKLEAK_METRICS + current->prev_lowest_stack = kstack_ptr; +#endif + /* * Now write the poison value to the kernel stack. Start from * 'kstack_ptr' and move up till the new 'boundary'. We assume that diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index c65fdd823591..b0a015ef5268 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -170,4 +170,16 @@ config STACKLEAK_TRACK_MIN_SIZE a stack frame size greater than or equal to this parameter. If unsure, leave the default value 100. +config STACKLEAK_METRICS + bool "Show STACKLEAK metrics in the /proc file system" + depends on GCC_PLUGIN_STACKLEAK + depends on PROC_FS + help + If this is set, STACKLEAK metrics for every task are available in + the /proc file system. In particular, /proc//stack_depth + shows the maximum kernel stack consumption for the current and + previous syscalls. Although this information is not precise, it + can be useful for estimating the STACKLEAK performance impact for + your workloads. + endif -- cgit v1.3-6-gb490 From 964c9dff0091893a9a74a88edf984c6da0b779f7 Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Fri, 17 Aug 2018 01:17:03 +0300 Subject: stackleak: Allow runtime disabling of kernel stack erasing Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides 'stack_erasing' sysctl. It can be used in runtime to control kernel stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK. Suggested-by: Ingo Molnar Signed-off-by: Alexander Popov Tested-by: Laura Abbott Signed-off-by: Kees Cook --- Documentation/sysctl/kernel.txt | 18 ++++++++++++++++++ include/linux/stackleak.h | 6 ++++++ kernel/stackleak.c | 38 ++++++++++++++++++++++++++++++++++++++ kernel/sysctl.c | 15 ++++++++++++++- scripts/gcc-plugins/Kconfig | 8 ++++++++ 5 files changed, 84 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 37a679501ddc..1b8775298cf7 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -89,6 +89,7 @@ show up in /proc/sys/kernel: - shmmni - softlockup_all_cpu_backtrace - soft_watchdog +- stack_erasing - stop-a [ SPARC only ] - sysrq ==> Documentation/admin-guide/sysrq.rst - sysctl_writes_strict @@ -987,6 +988,23 @@ detect a hard lockup condition. ============================================================== +stack_erasing + +This parameter can be used to control kernel stack erasing at the end +of syscalls for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK. + +That erasing reduces the information which kernel stack leak bugs +can reveal and blocks some uninitialized stack variable attacks. +The tradeoff is the performance impact: on a single CPU system kernel +compilation sees a 1% slowdown, other systems and workloads may vary. + + 0: kernel stack erasing is disabled, STACKLEAK_METRICS are not updated. + + 1: kernel stack erasing is enabled (default), it is performed before + returning to the userspace at the end of syscalls. + +============================================================== + tainted: Non-zero if the kernel has been tainted. Numeric values, which can be diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index b911b973d328..3d5c3271a9a8 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -22,6 +22,12 @@ static inline void stackleak_task_init(struct task_struct *t) t->prev_lowest_stack = t->lowest_stack; # endif } + +#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE +int stack_erasing_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos); +#endif + #else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ static inline void stackleak_task_init(struct task_struct *t) { } #endif diff --git a/kernel/stackleak.c b/kernel/stackleak.c index f66239572c89..e42892926244 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -12,6 +12,41 @@ #include +#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE +#include +#include + +static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass); + +int stack_erasing_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = 0; + int state = !static_branch_unlikely(&stack_erasing_bypass); + int prev_state = state; + + table->data = &state; + table->maxlen = sizeof(int); + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + state = !!state; + if (ret || !write || state == prev_state) + return ret; + + if (state) + static_branch_disable(&stack_erasing_bypass); + else + static_branch_enable(&stack_erasing_bypass); + + pr_warn("stackleak: kernel stack erasing is %s\n", + state ? "enabled" : "disabled"); + return ret; +} + +#define skip_erasing() static_branch_unlikely(&stack_erasing_bypass) +#else +#define skip_erasing() false +#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */ + asmlinkage void stackleak_erase(void) { /* It would be nice not to have 'kstack_ptr' and 'boundary' on stack */ @@ -20,6 +55,9 @@ asmlinkage void stackleak_erase(void) unsigned int poison_count = 0; const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + if (skip_erasing()) + return; + /* Check that 'lowest_stack' value is sane */ if (unlikely(kstack_ptr - boundary >= THREAD_SIZE)) kstack_ptr = boundary; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index cc02050fd0c4..3ae223f7b5df 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -91,7 +91,9 @@ #ifdef CONFIG_CHR_DEV_SG #include #endif - +#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE +#include +#endif #ifdef CONFIG_LOCKUP_DETECTOR #include #endif @@ -1232,6 +1234,17 @@ static struct ctl_table kern_table[] = { .extra1 = &zero, .extra2 = &one, }, +#endif +#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE + { + .procname = "stack_erasing", + .data = NULL, + .maxlen = sizeof(int), + .mode = 0600, + .proc_handler = stack_erasing_sysctl, + .extra1 = &zero, + .extra2 = &one, + }, #endif { } }; diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index b0a015ef5268..0d5c799688f0 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -182,4 +182,12 @@ config STACKLEAK_METRICS can be useful for estimating the STACKLEAK performance impact for your workloads. +config STACKLEAK_RUNTIME_DISABLE + bool "Allow runtime disabling of kernel stack erasing" + depends on GCC_PLUGIN_STACKLEAK + help + This option provides 'stack_erasing' sysctl, which can be used in + runtime to control kernel stack erasing for kernels built with + CONFIG_GCC_PLUGIN_STACKLEAK. + endif -- cgit v1.3-6-gb490 From 23066c3f4e2146da8c7d1505729f4409f4d93d28 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Wed, 19 Sep 2018 02:31:58 +0200 Subject: Compiler Attributes: enable -Wstringop-truncation on W=1 (gcc >= 8) Commit 217c3e019675 ("disable stringop truncation warnings for now") disabled -Wstringop-truncation since it was too noisy. Having __nonstring available allows us to let GCC know that a string is not meant to be NUL-terminated, which helps suppressing some -Wstringop-truncation warnings. Note that using __nonstring actually triggers other warnings (-Wstringop-overflow, which is on by default) which may be real problems. Therefore, cleaning up -Wstringop-truncation warnings also buys us the ability to uncover further potential problems. To encourage the use of __nonstring, we put the warning back at W=1. In the future, if we end up with a fairly warning-free tree, we might want to enable it by default. Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- scripts/Makefile.extrawarn | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 8d5357053f86..b8f36f5f43f2 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -29,6 +29,7 @@ warning-1 += $(call cc-option, -Wmissing-include-dirs) warning-1 += $(call cc-option, -Wunused-but-set-variable) warning-1 += $(call cc-option, -Wunused-const-variable) warning-1 += $(call cc-option, -Wpacked-not-aligned) +warning-1 += $(call cc-option, -Wstringop-truncation) warning-1 += $(call cc-disable-warning, missing-field-initializers) warning-1 += $(call cc-disable-warning, sign-compare) -- cgit v1.3-6-gb490 From 04c459d204484fa4747d29c24f00df11fe6334d4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 30 Oct 2018 00:41:27 +0900 Subject: kconfig: remove oldnoconfig target As commit 312ee68752fa ("kconfig: announce removal of oldnoconfig if used") announced, it is time for the removal. Signed-off-by: Masahiro Yamada --- scripts/kconfig/Makefile | 9 +-------- scripts/kconfig/conf.c | 7 ------- 2 files changed, 1 insertion(+), 15 deletions(-) (limited to 'scripts') diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile index 67ed9f6ccdf8..5d37a604ecc8 100644 --- a/scripts/kconfig/Makefile +++ b/scripts/kconfig/Makefile @@ -68,14 +68,7 @@ PHONY += $(simple-targets) $(simple-targets): $(obj)/conf $< $(silent) --$@ $(Kconfig) -PHONY += oldnoconfig silentoldconfig savedefconfig defconfig - -# oldnoconfig is an alias of olddefconfig, because people already are dependent -# on its behavior (sets new symbols to their default value but not 'n') with the -# counter-intuitive name. -oldnoconfig: olddefconfig - @echo " WARNING: \"oldnoconfig\" target will be removed after Linux 4.19" - @echo " Please use \"olddefconfig\" instead, which is an alias." +PHONY += silentoldconfig savedefconfig defconfig # We do not expect manual invokcation of "silentoldcofig" (or "syncconfig"). silentoldconfig: syncconfig diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c index 7b2b37260669..98e0c7a34699 100644 --- a/scripts/kconfig/conf.c +++ b/scripts/kconfig/conf.c @@ -460,12 +460,6 @@ static struct option long_opts[] = { {"randconfig", no_argument, NULL, randconfig}, {"listnewconfig", no_argument, NULL, listnewconfig}, {"olddefconfig", no_argument, NULL, olddefconfig}, - /* - * oldnoconfig is an alias of olddefconfig, because people already - * are dependent on its behavior(sets new symbols to their default - * value but not 'n') with the counter-intuitive name. - */ - {"oldnoconfig", no_argument, NULL, olddefconfig}, {NULL, 0, NULL, 0} }; @@ -480,7 +474,6 @@ static void conf_usage(const char *progname) printf(" --syncconfig Similar to oldconfig but generates configuration in\n" " include/{generated/,config/}\n"); printf(" --olddefconfig Same as oldconfig but sets new symbols to their default value\n"); - printf(" --oldnoconfig An alias of olddefconfig\n"); printf(" --defconfig New config with default defined in \n"); printf(" --savedefconfig Save the minimal current configuration to \n"); printf(" --allnoconfig New config where all options are answered with no\n"); -- cgit v1.3-6-gb490 From 0085b4191f3e30ec94beef4103679f2828d3c54f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 30 Oct 2018 00:41:28 +0900 Subject: kconfig: remove silentoldconfig target As commit 911a91c39cab ("kconfig: rename silentoldconfig to syncconfig") announced, it is time for the removal. Signed-off-by: Masahiro Yamada Acked-by: Jeff Kirsher --- Documentation/networking/ice.rst | 2 +- scripts/kconfig/Makefile | 9 +-------- 2 files changed, 2 insertions(+), 9 deletions(-) (limited to 'scripts') diff --git a/Documentation/networking/ice.rst b/Documentation/networking/ice.rst index 1e4948c9e989..4d118b827bbb 100644 --- a/Documentation/networking/ice.rst +++ b/Documentation/networking/ice.rst @@ -20,7 +20,7 @@ Enabling the driver The driver is enabled via the standard kernel configuration system, using the make command:: - make oldconfig/silentoldconfig/menuconfig/etc. + make oldconfig/menuconfig/etc. The driver is located in the menu structure at: diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile index 5d37a604ecc8..63b609243d03 100644 --- a/scripts/kconfig/Makefile +++ b/scripts/kconfig/Makefile @@ -68,14 +68,7 @@ PHONY += $(simple-targets) $(simple-targets): $(obj)/conf $< $(silent) --$@ $(Kconfig) -PHONY += silentoldconfig savedefconfig defconfig - -# We do not expect manual invokcation of "silentoldcofig" (or "syncconfig"). -silentoldconfig: syncconfig - @echo " WARNING: \"silentoldconfig\" has been renamed to \"syncconfig\"" - @echo " and is now an internal implementation detail." - @echo " What you want is probably \"oldconfig\"." - @echo " \"silentoldconfig\" will be removed after Linux 4.19" +PHONY += savedefconfig defconfig savedefconfig: $(obj)/conf $< $(silent) --$@=defconfig $(Kconfig) -- cgit v1.3-6-gb490 From 3f80babd9ca477d19a027e0b25b95973cd7f7357 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 30 Oct 2018 01:03:54 +0900 Subject: kbuild: remove unused cc-fullversion variable The last user of cc-fullversion was removed by commit f2910f0e6835 ("powerpc: remove old GCC version checks"). Signed-off-by: Masahiro Yamada --- Documentation/kbuild/makefiles.txt | 15 --------------- scripts/Kbuild.include | 4 ---- 2 files changed, 19 deletions(-) (limited to 'scripts') diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 7b6a2b2bdc98..8da26c6dd886 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -537,21 +537,6 @@ more details, with real examples. The third parameter may be a text as in this example, but it may also be an expanded variable or a macro. - cc-fullversion - cc-fullversion is useful when the exact version of gcc is needed. - One typical use-case is when a specific GCC version is broken. - cc-fullversion points out a more specific version than cc-version does. - - Example: - #arch/powerpc/Makefile - $(Q)if test "$(cc-fullversion)" = "040200" ; then \ - echo -n '*** GCC-4.2.0 cannot compile the 64-bit powerpc ' ; \ - false ; \ - fi - - In this example for a specific GCC version the build will error out - explaining to the user why it stops. - cc-cross-prefix cc-cross-prefix is used to check if there exists a $(CC) in path with one of the listed prefixes. The first prefix where there exist a diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index ca21a35fa244..19a63db62fb9 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -147,10 +147,6 @@ cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo # cc-version cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) -# cc-fullversion -cc-fullversion = $(shell $(CONFIG_SHELL) \ - $(srctree)/scripts/gcc-version.sh -p $(CC)) - # cc-ifversion # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4)) -- cgit v1.3-6-gb490 From 2cd3faf87d2d8f6123adf34741b9a7b98828a76f Mon Sep 17 00:00:00 2001 From: Petr Vorel Date: Mon, 29 Oct 2018 22:10:58 +0100 Subject: merge_config.sh: Allow to define config prefix with CONFIG_ environment variable. merge_config.sh uses CONFIG_ which is used in kernel and other projects. There are some projects which use kconfig with different prefixes (e.g. buildroot: BR2_ prefix). CONFIG_ variable is already used for this purpose in kconfig binary (scripts/kconfig/lkc.h), let's use the same rule for in merge_config.sh. Suggested-by: Masahiro Yamada Signed-off-by: Petr Vorel Signed-off-by: Masahiro Yamada --- scripts/kconfig/merge_config.sh | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh index 67d131447631..da66e7742282 100755 --- a/scripts/kconfig/merge_config.sh +++ b/scripts/kconfig/merge_config.sh @@ -33,12 +33,15 @@ usage() { echo " -n use allnoconfig instead of alldefconfig" echo " -r list redundant entries when merging fragments" echo " -O dir to put generated output files. Consider setting \$KCONFIG_CONFIG instead." + echo + echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable." } RUNMAKE=true ALLTARGET=alldefconfig WARNREDUN=false OUTPUT=. +CONFIG_PREFIX=${CONFIG_-CONFIG_} while true; do case $1 in @@ -99,7 +102,8 @@ if [ ! -r "$INITFILE" ]; then fi MERGE_LIST=$* -SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(CONFIG_[a-zA-Z0-9_]*\)[= ].*/\2/p" +SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)[= ].*/\2/p" + TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX) echo "Using $INITFILE as base" -- cgit v1.3-6-gb490 From 076f421da5d4594d0a3e60c032ccf02ba55e868a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 30 Oct 2018 22:26:33 +0900 Subject: kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Evaluating cc-name invokes the compiler every time even when you are not compiling anything, like 'make help'. This is not efficient. The compiler type has been already detected in the Kconfig stage. Use CONFIG_CC_IS_CLANG, instead. Signed-off-by: Masahiro Yamada Acked-by: Michael Ellerman (powerpc) Acked-by: Paul Burton (MIPS) Acked-by: Joel Stanley --- Makefile | 2 +- arch/mips/Makefile | 2 +- arch/mips/vdso/Makefile | 2 +- arch/powerpc/Makefile | 4 ++-- scripts/Makefile.extrawarn | 2 +- 5 files changed, 6 insertions(+), 6 deletions(-) (limited to 'scripts') diff --git a/Makefile b/Makefile index 9aa352b38815..8d6529c371e1 100644 --- a/Makefile +++ b/Makefile @@ -702,7 +702,7 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong KBUILD_CFLAGS += $(stackp-flags-y) -ifeq ($(cc-name),clang) +ifdef CONFIG_CC_IS_CLANG KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,) KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier) KBUILD_CFLAGS += $(call cc-disable-warning, gnu) diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 15a84cfd0719..68410490e12f 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -128,7 +128,7 @@ cflags-y += -ffreestanding # clang's output will be based upon the build machine. So for clang we simply # unconditionally specify -EB or -EL as appropriate. # -ifeq ($(cc-name),clang) +ifdef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_BIG_ENDIAN) += -EB cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -EL else diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 34605ca21498..58a0315ad743 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -10,7 +10,7 @@ ccflags-vdso := \ $(filter -march=%,$(KBUILD_CFLAGS)) \ -D__VDSO__ -ifeq ($(cc-name),clang) +ifdef CONFIG_CC_IS_CLANG ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS)) endif diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 17be664dafa2..8a2ce14d68d0 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -96,7 +96,7 @@ aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1) aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mabi=elfv2 endif -ifneq ($(cc-name),clang) +ifndef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mno-strict-align endif @@ -175,7 +175,7 @@ endif # Work around gcc code-gen bugs with -pg / -fno-omit-frame-pointer in gcc <= 4.8 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44199 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52828 -ifneq ($(cc-name),clang) +ifndef CONFIG_CC_IS_CLANG CC_FLAGS_FTRACE += $(call cc-ifversion, -lt, 0409, -mno-sched-epilog) endif endif diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 24b2fb1d1297..800a10f1b4f3 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -64,7 +64,7 @@ endif KBUILD_CFLAGS += $(warning) else -ifeq ($(cc-name),clang) +ifdef CONFIG_CC_IS_CLANG KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides) KBUILD_CFLAGS += $(call cc-disable-warning, unused-value) KBUILD_CFLAGS += $(call cc-disable-warning, format) -- cgit v1.3-6-gb490 From 995167420797c000bff1f0787ab2390ffa1a9784 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 30 Oct 2018 22:26:34 +0900 Subject: kbuild: remove cc-name variable There is one more user of $(cc-name) in the top Makefile. It is supposed to detect Clang before invoking Kconfig, so it should still be there in the $(shell ...) form. All the other users of $(cc-name) have been replaced with $(CONFIG_CC_IS_CLANG). Hence, scripts/Kbuild.include does not need to define cc-name any more. Signed-off-by: Masahiro Yamada --- Makefile | 2 +- scripts/Kbuild.include | 4 ---- 2 files changed, 1 insertion(+), 5 deletions(-) (limited to 'scripts') diff --git a/Makefile b/Makefile index 8d6529c371e1..bce41f4180fc 100644 --- a/Makefile +++ b/Makefile @@ -485,7 +485,7 @@ ifneq ($(KBUILD_SRC),) $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree) endif -ifeq ($(cc-name),clang) +ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) ifneq ($(CROSS_COMPILE),) CLANG_TARGET := --target=$(notdir $(CROSS_COMPILE:%-=%)) GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD))) diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 19a63db62fb9..bb015551c2d9 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -140,10 +140,6 @@ cc-option-yn = $(call try-run,\ cc-disable-warning = $(call try-run,\ $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) -# cc-name -# Expands to either gcc or clang -cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc) - # cc-version cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) -- cgit v1.3-6-gb490 From 21b42eb46834f6245a55ac77bdf3e14c034e2864 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 5 Nov 2018 16:51:49 +0900 Subject: kbuild: rpm-pkg: fix binrpm-pkg breakage when O= is used Zhenzhong Duan reported that running 'make O=/build/kernel binrpm-pkg' failed with the following errors: Running 'make O=/build/kernel binrpm-pkg' failed with below two errors. Makefile:600: include/config/auto.conf: No such file or directory + cp make -C /mnt/root/kernel O=/build/kernel image_name make -f /mnt/root/kernel/Makefile ... cp: invalid option -- 'C' Try 'cp --help' for more information. Prior to commit 80463f1b7bf9 ("kbuild: add --include-dir flag only for out-of-tree build"), both srctree and objtree were added to --include-dir redundantly, and the wrong code 'make image_name' was working by relying on that. Now, the potential issue that had previously been hidden just showed up. 'make image_name' recurses to the generated $(objtree)/Makefile and ends up with running in srctree, which is incorrect. It should be invoked with '-f $srctree/Makefile' (or KBUILD_SRC=) to be executed in objtree. Fixes: 80463f1b7bf9 ("kbuild: add --include-dir flag only for out-of-tree build") Reported-by: Zhenzhong Duan Signed-off-by: Masahiro Yamada --- scripts/package/mkspec | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'scripts') diff --git a/scripts/package/mkspec b/scripts/package/mkspec index e05646dc24dc..009147d4718e 100755 --- a/scripts/package/mkspec +++ b/scripts/package/mkspec @@ -12,6 +12,7 @@ # how we were called determines which rpms we build and how we build them if [ "$1" = prebuilt ]; then S=DEL + MAKE="$MAKE -f $srctree/Makefile" else S= fi @@ -78,19 +79,19 @@ $S %prep $S %setup -q $S $S %build -$S make %{?_smp_mflags} KBUILD_BUILD_VERSION=%{release} +$S $MAKE %{?_smp_mflags} KBUILD_BUILD_VERSION=%{release} $S %install mkdir -p %{buildroot}/boot %ifarch ia64 mkdir -p %{buildroot}/boot/efi - cp \$(make image_name) %{buildroot}/boot/efi/vmlinuz-$KERNELRELEASE + cp \$($MAKE image_name) %{buildroot}/boot/efi/vmlinuz-$KERNELRELEASE ln -s efi/vmlinuz-$KERNELRELEASE %{buildroot}/boot/ %else - cp \$(make image_name) %{buildroot}/boot/vmlinuz-$KERNELRELEASE + cp \$($MAKE image_name) %{buildroot}/boot/vmlinuz-$KERNELRELEASE %endif -$M make %{?_smp_mflags} INSTALL_MOD_PATH=%{buildroot} KBUILD_SRC= modules_install - make %{?_smp_mflags} INSTALL_HDR_PATH=%{buildroot}/usr KBUILD_SRC= headers_install +$M $MAKE %{?_smp_mflags} INSTALL_MOD_PATH=%{buildroot} modules_install + $MAKE %{?_smp_mflags} INSTALL_HDR_PATH=%{buildroot}/usr headers_install cp System.map %{buildroot}/boot/System.map-$KERNELRELEASE cp .config %{buildroot}/boot/config-$KERNELRELEASE bzip2 -9 --keep vmlinux -- cgit v1.3-6-gb490 From 02826a6ba301b72461c3706e1cc66d5571cd327e Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 5 Nov 2018 16:52:34 +0900 Subject: kbuild: deb-pkg: fix bindeb-pkg breakage when O= is used Ard Biesheuvel reports bindeb-pkg with O= option is broken in the following way: ... LD [M] sound/soc/rockchip/snd-soc-rk3399-gru-sound.ko LD [M] sound/soc/rockchip/snd-soc-rockchip-pcm.ko LD [M] sound/soc/rockchip/snd-soc-rockchip-rt5645.ko LD [M] sound/soc/rockchip/snd-soc-rockchip-spdif.ko LD [M] sound/soc/sh/rcar/snd-soc-rcar.ko fakeroot -u debian/rules binary make KERNELRELEASE=4.19.0-12677-g19beffaf7a99-dirty ARCH=arm64 KBUILD_SRC= intdeb-pkg /bin/bash /home/ard/linux/scripts/package/builddeb Makefile:600: include/config/auto.conf: No such file or directory *** *** Configuration file ".config" not found! *** *** Please run some configurator (e.g. "make oldconfig" or *** "make menuconfig" or "make xconfig"). *** make[12]: *** [syncconfig] Error 1 make[11]: *** [syncconfig] Error 2 make[10]: *** [include/config/auto.conf] Error 2 make[9]: *** [__sub-make] Error 2 ... Prior to commit 80463f1b7bf9 ("kbuild: add --include-dir flag only for out-of-tree build"), both srctree and objtree were added to --include-dir redundantly, and the wrong code '$MAKE image_name' was working by relying on that. Now, the potential issue that had previously been hidden just showed up. '$MAKE image_name' recurses to the generated $(objtree)/Makefile and ends up with running in srctree, which is incorrect. It should be invoked with '-f $srctree/Makefile' (or KBUILD_SRC=) to be executed in objtree. Fixes: 80463f1b7bf9 ("kbuild: add --include-dir flag only for out-of-tree build") Reported-by: Ard Biesheuvel Signed-off-by: Masahiro Yamada Tested-by: Ard Biesheuvel --- scripts/package/builddeb | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/package/builddeb b/scripts/package/builddeb index 90c9a8ac7adb..0b31f4f1f92c 100755 --- a/scripts/package/builddeb +++ b/scripts/package/builddeb @@ -81,7 +81,7 @@ else cp System.map "$tmpdir/boot/System.map-$version" cp $KCONFIG_CONFIG "$tmpdir/boot/config-$version" fi -cp "$($MAKE -s image_name)" "$tmpdir/$installed_image_path" +cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path" if grep -q "^CONFIG_OF=y" $KCONFIG_CONFIG ; then # Only some architectures with OF support have this target -- cgit v1.3-6-gb490 From 6bbe4385d035c6fac56f840a59861a0310ce137b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 5 Nov 2018 17:19:36 +0900 Subject: kconfig: merge_config: avoid false positive matches from comment lines The current SED_CONFIG_EXP could match to comment lines in config fragment files, especially when CONFIG_PREFIX_ is empty. For example, Buildroot uses empty prefixing; starting symbols with BR2_ is just convention. Make the sed expression more robust against false positives from comment lines. The new sed expression matches to only valid patterns. Signed-off-by: Masahiro Yamada Reviewed-by: Petr Vorel Reviewed-by: Arnout Vandecappelle (Essensium/Mind) --- scripts/kconfig/merge_config.sh | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'scripts') diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh index da66e7742282..0ef906499646 100755 --- a/scripts/kconfig/merge_config.sh +++ b/scripts/kconfig/merge_config.sh @@ -102,7 +102,8 @@ if [ ! -r "$INITFILE" ]; then fi MERGE_LIST=$* -SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)[= ].*/\2/p" +SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p" +SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p" TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX) @@ -116,7 +117,7 @@ for MERGE_FILE in $MERGE_LIST ; do echo "The merge file '$MERGE_FILE' does not exist. Exit." >&2 exit 1 fi - CFG_LIST=$(sed -n "$SED_CONFIG_EXP" $MERGE_FILE) + CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE) for CFG in $CFG_LIST ; do grep -q -w $CFG $TMP_FILE || continue @@ -159,7 +160,7 @@ make KCONFIG_ALLCONFIG=$TMP_FILE $OUTPUT_ARG $ALLTARGET # Check all specified config values took (might have missed-dependency issues) -for CFG in $(sed -n "$SED_CONFIG_EXP" $TMP_FILE); do +for CFG in $(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $TMP_FILE); do REQUESTED_VAL=$(grep -w -e "$CFG" $TMP_FILE) ACTUAL_VAL=$(grep -w -e "$CFG" "$KCONFIG_CONFIG") -- cgit v1.3-6-gb490 From bbcde0a7241261cd0ca8d8e6b94a4113a4b71443 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 6 Nov 2018 13:18:05 +0900 Subject: kbuild: deb-pkg: fix too low build version number Since commit b41d920acff8 ("kbuild: deb-pkg: split generating packaging and build"), the build version of the kernel contained in a deb package is too low by 1. Prior to the bad commit, the kernel was built first, then the number in .version file was read out, and written into the debian control file. Now, the debian control file is created before the kernel is actually compiled, which is causing the version number mismatch. Let the mkdebian script pass KBUILD_BUILD_VERSION=${revision} to require the build system to use the specified version number. Fixes: b41d920acff8 ("kbuild: deb-pkg: split generating packaging and build") Reported-by: Doug Smythies Signed-off-by: Masahiro Yamada Tested-by: Doug Smythies --- scripts/package/mkdebian | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/package/mkdebian b/scripts/package/mkdebian index 663a7f343b42..edcad61fe3cd 100755 --- a/scripts/package/mkdebian +++ b/scripts/package/mkdebian @@ -88,6 +88,7 @@ set_debarch() { version=$KERNELRELEASE if [ -n "$KDEB_PKGVERSION" ]; then packageversion=$KDEB_PKGVERSION + revision=${packageversion##*-} else revision=$(cat .version 2>/dev/null||echo 1) packageversion=$version-$revision @@ -205,10 +206,12 @@ cat < debian/rules #!$(command -v $MAKE) -f build: - \$(MAKE) KERNELRELEASE=${version} ARCH=${ARCH} KBUILD_SRC= + \$(MAKE) KERNELRELEASE=${version} ARCH=${ARCH} \ + KBUILD_BUILD_VERSION=${revision} KBUILD_SRC= binary-arch: - \$(MAKE) KERNELRELEASE=${version} ARCH=${ARCH} KBUILD_SRC= intdeb-pkg + \$(MAKE) KERNELRELEASE=${version} ARCH=${ARCH} \ + KBUILD_BUILD_VERSION=${revision} KBUILD_SRC= intdeb-pkg clean: rm -rf debian/*tmp debian/files -- cgit v1.3-6-gb490 From 8ef14c2c41d962756d314f1d7dc972b0ea7a180f Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 6 Nov 2018 10:10:38 -0800 Subject: Revert "scripts/setlocalversion: git: Make -dirty check more robust" This reverts commit 6147b1cf19651c7de297e69108b141fb30aa2349. The reverted patch results in attempted write access to the source repository, even if that repository is mounted read-only. Output from "strace git status -uno --porcelain": getcwd("/tmp/linux-test", 129) = 16 open("/tmp/linux-test/.git/index.lock", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = -1 EROFS (Read-only file system) While git appears to be able to handle this situation, a monitored build environment (such as the one used for Chrome OS kernel builds) may detect it and bail out with an access violation error. On top of that, the attempted write access suggests that git _will_ write to the file even if a build output directory is specified. Users may have the reasonable expectation that the source repository remains untouched in that situation. Fixes: 6147b1cf19651 ("scripts/setlocalversion: git: Make -dirty check more robust" Cc: Genki Sky Signed-off-by: Guenter Roeck Reviewed-by: Brian Norris Signed-off-by: Masahiro Yamada --- scripts/setlocalversion | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/setlocalversion b/scripts/setlocalversion index 79f7dd57d571..71f39410691b 100755 --- a/scripts/setlocalversion +++ b/scripts/setlocalversion @@ -74,7 +74,7 @@ scm_version() fi # Check for uncommitted changes - if git status -uno --porcelain | grep -qv '^.. scripts/package'; then + if git diff-index --name-only HEAD | grep -qv "^scripts/package"; then printf '%s' -dirty fi -- cgit v1.3-6-gb490 From d5615e472d23e854e96192103b6ae7977e705f01 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Wed, 7 Nov 2018 08:36:46 -0600 Subject: builddeb: Fix inclusion of dtbs in debian package MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb build rules") moved the location of 'dtbs_install' target which caused dtbs to not be installed when building debian package with 'bindeb-pkg' target. Update the builddeb script to use the same logic that determines if there's a 'dtbs_install' target which is presence of the arch dts directory. Also, use CONFIG_OF_EARLY_FLATTREE instead of CONFIG_OF as that's a better indication of whether we are building dtbs. This commit will also have the side effect of installing dtbs on any arch that has dts files. Previously, it was dependent on whether the arch defined 'dtbs_install'. Fixes: 37c8a5fafa3b ("kbuild: consolidate Devicetree dtb build rules") Reported-by: Nuno Gonçalves Signed-off-by: Rob Herring Signed-off-by: Masahiro Yamada --- scripts/package/builddeb | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/package/builddeb b/scripts/package/builddeb index 0b31f4f1f92c..f43a274f4f1d 100755 --- a/scripts/package/builddeb +++ b/scripts/package/builddeb @@ -83,9 +83,9 @@ else fi cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path" -if grep -q "^CONFIG_OF=y" $KCONFIG_CONFIG ; then +if grep -q "^CONFIG_OF_EARLY_FLATTREE=y" $KCONFIG_CONFIG ; then # Only some architectures with OF support have this target - if grep -q dtbs_install "${srctree}/arch/$SRCARCH/Makefile"; then + if [ -d "${srctree}/arch/$SRCARCH/boot/dts" ]; then $MAKE KBUILD_SRC= INSTALL_DTBS_PATH="$tmpdir/usr/lib/$packagename" dtbs_install fi fi -- cgit v1.3-6-gb490 From f5f67cc0e0d3d17ee046ba83f831f267767b8554 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Fri, 16 Nov 2018 15:08:22 -0800 Subject: scripts/faddr2line: fix location of start_kernel in comment Fix a source file reference location to the correct path name. Link: http://lkml.kernel.org/r/1d50bd3d-178e-dcd8-779f-9711887440eb@infradead.org Signed-off-by: Randy Dunlap Acked-by: Josh Poimboeuf Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/faddr2line | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/faddr2line b/scripts/faddr2line index a0149db00be7..6c6439f69a72 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -71,7 +71,7 @@ die() { # Try to figure out the source directory prefix so we can remove it from the # addr2line output. HACK ALERT: This assumes that start_kernel() is in -# kernel/init.c! This only works for vmlinux. Otherwise it falls back to +# init/main.c! This only works for vmlinux. Otherwise it falls back to # printing the absolute path. find_dir_prefix() { local objfile=$1 -- cgit v1.3-6-gb490 From 6f4d29df66acd49303a99025046b85cabe7aa17a Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Fri, 16 Nov 2018 15:08:43 -0800 Subject: scripts/spdxcheck.py: make python3 compliant MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Without this change the following happens when using Python3 (3.6.6): $ echo "GPL-2.0" | python3 scripts/spdxcheck.py - FAIL: 'str' object has no attribute 'decode' Traceback (most recent call last): File "scripts/spdxcheck.py", line 253, in parser.parse_lines(sys.stdin, args.maxlines, '-') File "scripts/spdxcheck.py", line 171, in parse_lines line = line.decode(locale.getpreferredencoding(False), errors='ignore') AttributeError: 'str' object has no attribute 'decode' So as the line is already a string, there is no need to decode it and the line can be dropped. /usr/bin/python on Arch is Python 3. So this would indeed be worth going into 4.19. Link: http://lkml.kernel.org/r/20181023070802.22558-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Cc: Thomas Gleixner Cc: Joe Perches Cc: Greg Kroah-Hartman Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/spdxcheck.py | 1 - 1 file changed, 1 deletion(-) (limited to 'scripts') diff --git a/scripts/spdxcheck.py b/scripts/spdxcheck.py index 839e190bbd7a..5056fb3b897d 100755 --- a/scripts/spdxcheck.py +++ b/scripts/spdxcheck.py @@ -168,7 +168,6 @@ class id_parser(object): self.curline = 0 try: for line in fd: - line = line.decode(locale.getpreferredencoding(False), errors='ignore') self.curline += 1 if self.curline > maxlines: break -- cgit v1.3-6-gb490 From 4cd24de3a0980bf3100c9dcb08ef65ca7c31af48 Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Fri, 2 Nov 2018 01:45:41 -0700 Subject: x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support Since retpoline capable compilers are widely available, make CONFIG_RETPOLINE hard depend on the compiler capability. Break the build when CONFIG_RETPOLINE is enabled and the compiler does not support it. Emit an error message in that case: "arch/x86/Makefile:226: *** You are building kernel with non-retpoline compiler, please update your compiler.. Stop." [dwmw: Fail the build with non-retpoline compiler] Suggested-by: Peter Zijlstra Signed-off-by: Zhenzhong Duan Signed-off-by: Thomas Gleixner Cc: David Woodhouse Cc: Borislav Petkov Cc: Daniel Borkmann Cc: H. Peter Anvin Cc: Konrad Rzeszutek Wilk Cc: Andy Lutomirski Cc: Masahiro Yamada Cc: Michal Marek Cc: Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/cca0cb20-f9e2-4094-840b-fb0f8810cd34@default --- arch/x86/Kconfig | 4 ---- arch/x86/Makefile | 5 +++-- arch/x86/include/asm/nospec-branch.h | 10 ++++++---- arch/x86/kernel/cpu/bugs.c | 2 +- scripts/Makefile.build | 2 -- 5 files changed, 10 insertions(+), 13 deletions(-) (limited to 'scripts') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9d734f3c8234..b5286ad2a982 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -444,10 +444,6 @@ config RETPOLINE branches. Requires a compiler with -mindirect-branch=thunk-extern support for full protection. The kernel may run slower. - Without compiler support, at least indirect branches in assembler - code are eliminated. Since this includes the syscall entry path, - it is not entirely pointless. - config INTEL_RDT bool "Intel Resource Director Technology support" depends on X86 && CPU_SUP_INTEL diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 88398fdf8129..f5d7f4134524 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -220,9 +220,10 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables # Avoid indirect branches in kernel to deal with Spectre ifdef CONFIG_RETPOLINE -ifneq ($(RETPOLINE_CFLAGS),) - KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE +ifeq ($(RETPOLINE_CFLAGS),) + $(error You are building kernel with non-retpoline compiler, please update your compiler.) endif + KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) endif archscripts: scripts_basic diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 80dc14422495..8b09cbb2d52c 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -162,11 +162,12 @@ _ASM_PTR " 999b\n\t" \ ".popsection\n\t" -#if defined(CONFIG_X86_64) && defined(RETPOLINE) +#ifdef CONFIG_RETPOLINE +#ifdef CONFIG_X86_64 /* - * Since the inline asm uses the %V modifier which is only in newer GCC, - * the 64-bit one is dependent on RETPOLINE not CONFIG_RETPOLINE. + * Inline asm uses the %V modifier which is only in newer GCC + * which is ensured when CONFIG_RETPOLINE is defined. */ # define CALL_NOSPEC \ ANNOTATE_NOSPEC_ALTERNATIVE \ @@ -181,7 +182,7 @@ X86_FEATURE_RETPOLINE_AMD) # define THUNK_TARGET(addr) [thunk_target] "r" (addr) -#elif defined(CONFIG_X86_32) && defined(CONFIG_RETPOLINE) +#else /* CONFIG_X86_32 */ /* * For i386 we use the original ret-equivalent retpoline, because * otherwise we'll run out of registers. We don't care about CET @@ -211,6 +212,7 @@ X86_FEATURE_RETPOLINE_AMD) # define THUNK_TARGET(addr) [thunk_target] "rm" (addr) +#endif #else /* No retpoline for C / inline asm */ # define CALL_NOSPEC "call *%[thunk_target]\n" # define THUNK_TARGET(addr) [thunk_target] "rm" (addr) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index c37e66e493bf..d0108fb6e4dd 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -252,7 +252,7 @@ static void __init spec2_print_if_secure(const char *reason) static inline bool retp_compiler(void) { - return __is_defined(RETPOLINE); + return __is_defined(CONFIG_RETPOLINE); } static inline bool match_option(const char *arg, int arglen, const char *opt) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a8e7ba9f73e8..6a6be9f440cf 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -236,10 +236,8 @@ ifdef CONFIG_GCOV_KERNEL objtool_args += --no-unreachable endif ifdef CONFIG_RETPOLINE -ifneq ($(RETPOLINE_CFLAGS),) objtool_args += --retpoline endif -endif ifdef CONFIG_MODVERSIONS -- cgit v1.3-6-gb490 From 38c7b224ce22c25fed04007839edf974bd13439d Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 30 Nov 2018 14:45:01 -0800 Subject: unifdef: use memcpy instead of strncpy New versions of gcc reasonably warn about the odd pattern of strncpy(p, q, strlen(q)); which really doesn't make sense: the strncpy() ends up being just a slow and odd way to write memcpy() in this case. There was a comment about _why_ the code used strncpy - to avoid the terminating NUL byte, but memcpy does the same and avoids the warning. Signed-off-by: Linus Torvalds --- scripts/unifdef.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/unifdef.c b/scripts/unifdef.c index 7493c0ee51cc..db00e3e30a59 100644 --- a/scripts/unifdef.c +++ b/scripts/unifdef.c @@ -395,7 +395,7 @@ usage(void) * When we have processed a group that starts off with a known-false * #if/#elif sequence (which has therefore been deleted) followed by a * #elif that we don't understand and therefore must keep, we edit the - * latter into a #if to keep the nesting correct. We use strncpy() to + * latter into a #if to keep the nesting correct. We use memcpy() to * overwrite the 4 byte token "elif" with "if " without a '\0' byte. * * When we find a true #elif in a group, the following block will @@ -450,7 +450,7 @@ static void Idrop (void) { Fdrop(); ignoreon(); } static void Itrue (void) { Ftrue(); ignoreon(); } static void Ifalse(void) { Ffalse(); ignoreon(); } /* modify this line */ -static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); } +static void Mpass (void) { memcpy(keyword, "if ", 4); Pelif(); } static void Mtrue (void) { keywordedit("else"); state(IS_TRUE_MIDDLE); } static void Melif (void) { keywordedit("endif"); state(IS_FALSE_TRAILER); } static void Melse (void) { keywordedit("endif"); state(IS_FALSE_ELSE); } -- cgit v1.3-6-gb490 From 8fb2dfb228df785bbeb4d055a74402ef4b07fc25 Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Thu, 6 Dec 2018 18:13:07 +0300 Subject: stackleak: Register the 'stackleak_cleanup' pass before the '*free_cfg' pass Currently the 'stackleak_cleanup' pass deleting a CALL insn is executed after the 'reload' pass. That allows gcc to do some weird optimization in function prologues and epilogues, which are generated later [1]. Let's avoid that by registering the 'stackleak_cleanup' pass before the '*free_cfg' pass. It's the moment when the stack frame size is already final, function prologues and epilogues are generated, and the machine-dependent code transformations are not done. [1] https://www.openwall.com/lists/kernel-hardening/2018/11/23/2 Reported-by: kbuild test robot Signed-off-by: Alexander Popov Signed-off-by: Kees Cook --- scripts/gcc-plugins/stackleak_plugin.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'scripts') diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index 2f48da98b5d4..dbd37460c573 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -363,10 +363,12 @@ __visible int plugin_init(struct plugin_name_args *plugin_info, PASS_POS_INSERT_BEFORE); /* - * The stackleak_cleanup pass should be executed after the - * "reload" pass, when the stack frame size is final. + * The stackleak_cleanup pass should be executed before the "*free_cfg" + * pass. It's the moment when the stack frame size is already final, + * function prologues and epilogues are generated, and the + * machine-dependent code transformations are not done. */ - PASS_INFO(stackleak_cleanup, "reload", 1, PASS_POS_INSERT_AFTER); + PASS_INFO(stackleak_cleanup, "*free_cfg", 1, PASS_POS_INSERT_BEFORE); if (!plugin_default_version_check(version, &gcc_version)) { error(G_("incompatible gcc/plugin versions")); -- cgit v1.3-6-gb490