aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/tools/testing/selftests/x86
diff options
context:
space:
mode:
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r--tools/testing/selftests/x86/Makefile5
-rw-r--r--tools/testing/selftests/x86/fsgsbase.c223
-rw-r--r--tools/testing/selftests/x86/protection_keys.c2
-rw-r--r--tools/testing/selftests/x86/syscall_arg_fault.c112
-rw-r--r--tools/testing/selftests/x86/test_vsyscall.c120
5 files changed, 407 insertions, 55 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 186520198de7..fa07d526fe39 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -12,8 +12,9 @@ CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) trivial_program.c -no-pie)
TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
check_initial_reg_state sigreturn iopl mpx-mini-test ioperm \
- protection_keys test_vdso test_vsyscall mov_ss_trap
-TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \
+ protection_keys test_vdso test_vsyscall mov_ss_trap \
+ syscall_arg_fault
+TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
index af85bd4752a5..5ab4c60c100e 100644
--- a/tools/testing/selftests/x86/fsgsbase.c
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -23,6 +23,10 @@
#include <pthread.h>
#include <asm/ldt.h>
#include <sys/mman.h>
+#include <stddef.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <setjmp.h>
#ifndef __x86_64__
# error This test is 64-bit only
@@ -31,6 +35,8 @@
static volatile sig_atomic_t want_segv;
static volatile unsigned long segv_addr;
+static unsigned short *shared_scratch;
+
static int nerrs;
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
@@ -71,6 +77,43 @@ static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
}
+static jmp_buf jmpbuf;
+
+static void sigill(int sig, siginfo_t *si, void *ctx_void)
+{
+ siglongjmp(jmpbuf, 1);
+}
+
+static bool have_fsgsbase;
+
+static inline unsigned long rdgsbase(void)
+{
+ unsigned long gsbase;
+
+ asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory");
+
+ return gsbase;
+}
+
+static inline unsigned long rdfsbase(void)
+{
+ unsigned long fsbase;
+
+ asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory");
+
+ return fsbase;
+}
+
+static inline void wrgsbase(unsigned long gsbase)
+{
+ asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory");
+}
+
+static inline void wrfsbase(unsigned long fsbase)
+{
+ asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory");
+}
+
enum which_base { FS, GS };
static unsigned long read_base(enum which_base which)
@@ -199,16 +242,13 @@ static void do_remote_base()
to_set, hard_zero ? " and clear gs" : "", sel);
}
-void do_unexpected_base(void)
+static __thread int set_thread_area_entry_number = -1;
+
+static unsigned short load_gs(void)
{
/*
- * The goal here is to try to arrange for GS == 0, GSBASE !=
- * 0, and for the the kernel the think that GSBASE == 0.
- *
- * To make the test as reliable as possible, this uses
- * explicit descriptorss. (This is not the only way. This
- * could use ARCH_SET_GS with a low, nonzero base, but the
- * relevant side effect of ARCH_SET_GS could change.)
+ * Sets GS != 0 and GSBASE != 0 but arranges for the kernel to think
+ * that GSBASE == 0 (i.e. thread.gsbase == 0).
*/
/* Step 1: tell the kernel that we have GSBASE == 0. */
@@ -228,8 +268,9 @@ void do_unexpected_base(void)
.useable = 0
};
if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) == 0) {
- printf("\tother thread: using LDT slot 0\n");
+ printf("\tusing LDT slot 0\n");
asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0x7));
+ return 0x7;
} else {
/* No modify_ldt for us (configured out, perhaps) */
@@ -239,7 +280,7 @@ void do_unexpected_base(void)
MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
memcpy(low_desc, &desc, sizeof(desc));
- low_desc->entry_number = -1;
+ low_desc->entry_number = set_thread_area_entry_number;
/* 32-bit set_thread_area */
long ret;
@@ -251,18 +292,43 @@ void do_unexpected_base(void)
if (ret != 0) {
printf("[NOTE]\tcould not create a segment -- test won't do anything\n");
- return;
+ return 0;
}
- printf("\tother thread: using GDT slot %d\n", desc.entry_number);
- asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)((desc.entry_number << 3) | 0x3)));
+ printf("\tusing GDT slot %d\n", desc.entry_number);
+ set_thread_area_entry_number = desc.entry_number;
+
+ unsigned short gs = (unsigned short)((desc.entry_number << 3) | 0x3);
+ asm volatile ("mov %0, %%gs" : : "rm" (gs));
+ return gs;
}
+}
- /*
- * Step 3: set the selector back to zero. On AMD chips, this will
- * preserve GSBASE.
- */
+void test_wrbase(unsigned short index, unsigned long base)
+{
+ unsigned short newindex;
+ unsigned long newbase;
- asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+ printf("[RUN]\tGS = 0x%hx, GSBASE = 0x%lx\n", index, base);
+
+ asm volatile ("mov %0, %%gs" : : "rm" (index));
+ wrgsbase(base);
+
+ remote_base = 0;
+ ftx = 1;
+ syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+ while (ftx != 0)
+ syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+ asm volatile ("mov %%gs, %0" : "=rm" (newindex));
+ newbase = rdgsbase();
+
+ if (newindex == index && newbase == base) {
+ printf("[OK]\tIndex and base were preserved\n");
+ } else {
+ printf("[FAIL]\tAfter switch, GS = 0x%hx and GSBASE = 0x%lx\n",
+ newindex, newbase);
+ nerrs++;
+ }
}
static void *threadproc(void *ctx)
@@ -273,12 +339,19 @@ static void *threadproc(void *ctx)
if (ftx == 3)
return NULL;
- if (ftx == 1)
+ if (ftx == 1) {
do_remote_base();
- else if (ftx == 2)
- do_unexpected_base();
- else
+ } else if (ftx == 2) {
+ /*
+ * On AMD chips, this causes GSBASE != 0, GS == 0, and
+ * thread.gsbase == 0.
+ */
+
+ load_gs();
+ asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+ } else {
errx(1, "helper thread got bad command");
+ }
ftx = 0;
syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
@@ -367,10 +440,99 @@ static void test_unexpected_base(void)
}
}
+#define USER_REGS_OFFSET(r) offsetof(struct user_regs_struct, r)
+
+static void test_ptrace_write_gsbase(void)
+{
+ int status;
+ pid_t child = fork();
+
+ if (child < 0)
+ err(1, "fork");
+
+ if (child == 0) {
+ printf("[RUN]\tPTRACE_POKE(), write GSBASE from ptracer\n");
+
+ *shared_scratch = load_gs();
+
+ if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0)
+ err(1, "PTRACE_TRACEME");
+
+ raise(SIGTRAP);
+ _exit(0);
+ }
+
+ wait(&status);
+
+ if (WSTOPSIG(status) == SIGTRAP) {
+ unsigned long gs, base;
+ unsigned long gs_offset = USER_REGS_OFFSET(gs);
+ unsigned long base_offset = USER_REGS_OFFSET(gs_base);
+
+ gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL);
+
+ if (gs != *shared_scratch) {
+ nerrs++;
+ printf("[FAIL]\tGS is not prepared with nonzero\n");
+ goto END;
+ }
+
+ if (ptrace(PTRACE_POKEUSER, child, base_offset, 0xFF) != 0)
+ err(1, "PTRACE_POKEUSER");
+
+ gs = ptrace(PTRACE_PEEKUSER, child, gs_offset, NULL);
+ base = ptrace(PTRACE_PEEKUSER, child, base_offset, NULL);
+
+ /*
+ * In a non-FSGSBASE system, the nonzero selector will load
+ * GSBASE (again). But what is tested here is whether the
+ * selector value is changed or not by the GSBASE write in
+ * a ptracer.
+ */
+ if (gs != *shared_scratch) {
+ nerrs++;
+ printf("[FAIL]\tGS changed to %lx\n", gs);
+
+ /*
+ * On older kernels, poking a nonzero value into the
+ * base would zero the selector. On newer kernels,
+ * this behavior has changed -- poking the base
+ * changes only the base and, if FSGSBASE is not
+ * available, this may have no effect.
+ */
+ if (gs == 0)
+ printf("\tNote: this is expected behavior on older kernels.\n");
+ } else if (have_fsgsbase && (base != 0xFF)) {
+ nerrs++;
+ printf("[FAIL]\tGSBASE changed to %lx\n", base);
+ } else {
+ printf("[OK]\tGS remained 0x%hx%s", *shared_scratch, have_fsgsbase ? " and GSBASE changed to 0xFF" : "");
+ printf("\n");
+ }
+ }
+
+END:
+ ptrace(PTRACE_CONT, child, NULL, NULL);
+}
+
int main()
{
pthread_t thread;
+ shared_scratch = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+
+ /* Probe FSGSBASE */
+ sethandler(SIGILL, sigill, 0);
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ rdfsbase();
+ have_fsgsbase = true;
+ printf("\tFSGSBASE instructions are enabled\n");
+ } else {
+ printf("\tFSGSBASE instructions are disabled\n");
+ }
+ clearhandler(SIGILL);
+
sethandler(SIGSEGV, sigsegv, 0);
check_gs_value(0);
@@ -417,11 +579,28 @@ int main()
test_unexpected_base();
+ if (have_fsgsbase) {
+ unsigned short ss;
+
+ asm volatile ("mov %%ss, %0" : "=rm" (ss));
+
+ test_wrbase(0, 0);
+ test_wrbase(0, 1);
+ test_wrbase(0, 0x200000000);
+ test_wrbase(0, 0xffffffffffffffff);
+ test_wrbase(ss, 0);
+ test_wrbase(ss, 1);
+ test_wrbase(ss, 0x200000000);
+ test_wrbase(ss, 0xffffffffffffffff);
+ }
+
ftx = 3; /* Kill the thread. */
syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
if (pthread_join(thread, NULL) != 0)
err(1, "pthread_join");
+ test_ptrace_write_gsbase();
+
return nerrs == 0 ? 0 : 1;
}
diff --git a/tools/testing/selftests/x86/protection_keys.c b/tools/testing/selftests/x86/protection_keys.c
index 5d546dcdbc80..480995bceefa 100644
--- a/tools/testing/selftests/x86/protection_keys.c
+++ b/tools/testing/selftests/x86/protection_keys.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * Tests x86 Memory Protection Keys (see Documentation/x86/protection-keys.txt)
+ * Tests x86 Memory Protection Keys (see Documentation/core-api/protection-keys.rst)
*
* There are examples in here of:
* * how to set protection keys on memory
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index 4e25d38c8bbd..bc0ecc2e862e 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -15,9 +15,30 @@
#include <setjmp.h>
#include <errno.h>
+#ifdef __x86_64__
+# define WIDTH "q"
+#else
+# define WIDTH "l"
+#endif
+
/* Our sigaltstack scratch space. */
static unsigned char altstack_data[SIGSTKSZ];
+static unsigned long get_eflags(void)
+{
+ unsigned long eflags;
+ asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags));
+ return eflags;
+}
+
+static void set_eflags(unsigned long eflags)
+{
+ asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH
+ : : "rm" (eflags) : "flags");
+}
+
+#define X86_EFLAGS_TF (1UL << 8)
+
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
int flags)
{
@@ -35,13 +56,22 @@ static sigjmp_buf jmpbuf;
static volatile sig_atomic_t n_errs;
+#ifdef __x86_64__
+#define REG_AX REG_RAX
+#define REG_IP REG_RIP
+#else
+#define REG_AX REG_EAX
+#define REG_IP REG_EIP
+#endif
+
static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
{
ucontext_t *ctx = (ucontext_t*)ctx_void;
+ long ax = (long)ctx->uc_mcontext.gregs[REG_AX];
- if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) {
- printf("[FAIL]\tAX had the wrong value: 0x%x\n",
- ctx->uc_mcontext.gregs[REG_EAX]);
+ if (ax != -EFAULT && ax != -ENOSYS) {
+ printf("[FAIL]\tAX had the wrong value: 0x%lx\n",
+ (unsigned long)ax);
n_errs++;
} else {
printf("[OK]\tSeems okay\n");
@@ -50,9 +80,42 @@ static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
siglongjmp(jmpbuf, 1);
}
+static volatile sig_atomic_t sigtrap_consecutive_syscalls;
+
+static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+ /*
+ * KVM has some bugs that can cause us to stop making progress.
+ * detect them and complain, but don't infinite loop or fail the
+ * test.
+ */
+
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+ unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+ if (*ip == 0x340f || *ip == 0x050f) {
+ /* The trap was on SYSCALL or SYSENTER */
+ sigtrap_consecutive_syscalls++;
+ if (sigtrap_consecutive_syscalls > 3) {
+ printf("[WARN]\tGot stuck single-stepping -- you probably have a KVM bug\n");
+ siglongjmp(jmpbuf, 1);
+ }
+ } else {
+ sigtrap_consecutive_syscalls = 0;
+ }
+}
+
static void sigill(int sig, siginfo_t *info, void *ctx_void)
{
- printf("[SKIP]\tIllegal instruction\n");
+ ucontext_t *ctx = (ucontext_t*)ctx_void;
+ unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP];
+
+ if (*ip == 0x0b0f) {
+ /* one of the ud2 instructions faulted */
+ printf("[OK]\tSYSCALL returned normally\n");
+ } else {
+ printf("[SKIP]\tIllegal instruction\n");
+ }
siglongjmp(jmpbuf, 1);
}
@@ -120,9 +183,48 @@ int main()
"movl $-1, %%ebp\n\t"
"movl $-1, %%esp\n\t"
"syscall\n\t"
- "pushl $0" /* make sure we segfault cleanly */
+ "ud2" /* make sure we recover cleanly */
+ : : : "memory", "flags");
+ }
+
+ printf("[RUN]\tSYSENTER with TF and invalid state\n");
+ sethandler(SIGTRAP, sigtrap, SA_ONSTACK);
+
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ sigtrap_consecutive_syscalls = 0;
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "sysenter"
+ : : : "memory", "flags");
+ }
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
+
+ printf("[RUN]\tSYSCALL with TF and invalid state\n");
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ sigtrap_consecutive_syscalls = 0;
+ set_eflags(get_eflags() | X86_EFLAGS_TF);
+ asm volatile (
+ "movl $-1, %%eax\n\t"
+ "movl $-1, %%ebx\n\t"
+ "movl $-1, %%ecx\n\t"
+ "movl $-1, %%edx\n\t"
+ "movl $-1, %%esi\n\t"
+ "movl $-1, %%edi\n\t"
+ "movl $-1, %%ebp\n\t"
+ "movl $-1, %%esp\n\t"
+ "syscall\n\t"
+ "ud2" /* make sure we recover cleanly */
: : : "memory", "flags");
}
+ set_eflags(get_eflags() & ~X86_EFLAGS_TF);
return 0;
}
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index 0b4f1cc2291c..4602326b8f5b 100644
--- a/tools/testing/selftests/x86/test_vsyscall.c
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -18,6 +18,7 @@
#include <sched.h>
#include <stdbool.h>
#include <setjmp.h>
+#include <sys/uio.h>
#ifdef __x86_64__
# define VSYS(x) (x)
@@ -49,21 +50,21 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
}
/* vsyscalls and vDSO */
-bool should_read_vsyscall = false;
+bool vsyscall_map_r = false, vsyscall_map_x = false;
typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
-gtod_t vgtod = (gtod_t)VSYS(0xffffffffff600000);
+const gtod_t vgtod = (gtod_t)VSYS(0xffffffffff600000);
gtod_t vdso_gtod;
typedef int (*vgettime_t)(clockid_t, struct timespec *);
vgettime_t vdso_gettime;
typedef long (*time_func_t)(time_t *t);
-time_func_t vtime = (time_func_t)VSYS(0xffffffffff600400);
+const time_func_t vtime = (time_func_t)VSYS(0xffffffffff600400);
time_func_t vdso_time;
typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
-getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
+const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
getcpu_t vdso_getcpu;
static void init_vdso(void)
@@ -107,7 +108,7 @@ static int init_vsys(void)
maps = fopen("/proc/self/maps", "r");
if (!maps) {
printf("[WARN]\tCould not open /proc/self/maps -- assuming vsyscall is r-x\n");
- should_read_vsyscall = true;
+ vsyscall_map_r = true;
return 0;
}
@@ -133,12 +134,8 @@ static int init_vsys(void)
}
printf("\tvsyscall permissions are %c-%c\n", r, x);
- should_read_vsyscall = (r == 'r');
- if (x != 'x') {
- vgtod = NULL;
- vtime = NULL;
- vgetcpu = NULL;
- }
+ vsyscall_map_r = (r == 'r');
+ vsyscall_map_x = (x == 'x');
found = true;
break;
@@ -148,10 +145,8 @@ static int init_vsys(void)
if (!found) {
printf("\tno vsyscall map in /proc/self/maps\n");
- should_read_vsyscall = false;
- vgtod = NULL;
- vtime = NULL;
- vgetcpu = NULL;
+ vsyscall_map_r = false;
+ vsyscall_map_x = false;
}
return nerrs;
@@ -183,9 +178,13 @@ static inline long sys_getcpu(unsigned * cpu, unsigned * node,
}
static jmp_buf jmpbuf;
+static volatile unsigned long segv_err;
static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
{
+ ucontext_t *ctx = (ucontext_t *)ctx_void;
+
+ segv_err = ctx->uc_mcontext.gregs[REG_ERR];
siglongjmp(jmpbuf, 1);
}
@@ -238,7 +237,7 @@ static int test_gtod(void)
err(1, "syscall gettimeofday");
if (vdso_gtod)
ret_vdso = vdso_gtod(&tv_vdso, &tz_vdso);
- if (vgtod)
+ if (vsyscall_map_x)
ret_vsys = vgtod(&tv_vsys, &tz_vsys);
if (sys_gtod(&tv_sys2, &tz_sys) != 0)
err(1, "syscall gettimeofday");
@@ -252,7 +251,7 @@ static int test_gtod(void)
}
}
- if (vgtod) {
+ if (vsyscall_map_x) {
if (ret_vsys == 0) {
nerrs += check_gtod(&tv_sys1, &tv_sys2, &tz_sys, "vsyscall", &tv_vsys, &tz_vsys);
} else {
@@ -273,7 +272,7 @@ static int test_time(void) {
t_sys1 = sys_time(&t2_sys1);
if (vdso_time)
t_vdso = vdso_time(&t2_vdso);
- if (vtime)
+ if (vsyscall_map_x)
t_vsys = vtime(&t2_vsys);
t_sys2 = sys_time(&t2_sys2);
if (t_sys1 < 0 || t_sys1 != t2_sys1 || t_sys2 < 0 || t_sys2 != t2_sys2) {
@@ -294,7 +293,7 @@ static int test_time(void) {
}
}
- if (vtime) {
+ if (vsyscall_map_x) {
if (t_vsys < 0 || t_vsys != t2_vsys) {
printf("[FAIL]\tvsyscall failed (ret:%ld output:%ld)\n", t_vsys, t2_vsys);
nerrs++;
@@ -330,7 +329,7 @@ static int test_getcpu(int cpu)
ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
if (vdso_getcpu)
ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
- if (vgetcpu)
+ if (vsyscall_map_x)
ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
if (ret_sys == 0) {
@@ -369,7 +368,7 @@ static int test_getcpu(int cpu)
}
}
- if (vgetcpu) {
+ if (vsyscall_map_x) {
if (ret_vsys) {
printf("[FAIL]\tvsyscall getcpu() failed\n");
nerrs++;
@@ -410,20 +409,88 @@ static int test_vsys_r(void)
can_read = false;
}
- if (can_read && !should_read_vsyscall) {
+ if (can_read && !vsyscall_map_r) {
printf("[FAIL]\tWe have read access, but we shouldn't\n");
return 1;
- } else if (!can_read && should_read_vsyscall) {
+ } else if (!can_read && vsyscall_map_r) {
printf("[FAIL]\tWe don't have read access, but we should\n");
return 1;
+ } else if (can_read) {
+ printf("[OK]\tWe have read access\n");
} else {
- printf("[OK]\tgot expected result\n");
+ printf("[OK]\tWe do not have read access: #PF(0x%lx)\n",
+ segv_err);
}
#endif
return 0;
}
+static int test_vsys_x(void)
+{
+#ifdef __x86_64__
+ if (vsyscall_map_x) {
+ /* We already tested this adequately. */
+ return 0;
+ }
+
+ printf("[RUN]\tMake sure that vsyscalls really page fault\n");
+
+ bool can_exec;
+ if (sigsetjmp(jmpbuf, 1) == 0) {
+ vgtod(NULL, NULL);
+ can_exec = true;
+ } else {
+ can_exec = false;
+ }
+
+ if (can_exec) {
+ printf("[FAIL]\tExecuting the vsyscall did not page fault\n");
+ return 1;
+ } else if (segv_err & (1 << 4)) { /* INSTR */
+ printf("[OK]\tExecuting the vsyscall page failed: #PF(0x%lx)\n",
+ segv_err);
+ } else {
+ printf("[FAILT]\tExecution failed with the wrong error: #PF(0x%lx)\n",
+ segv_err);
+ return 1;
+ }
+#endif
+
+ return 0;
+}
+
+static int test_process_vm_readv(void)
+{
+#ifdef __x86_64__
+ char buf[4096];
+ struct iovec local, remote;
+ int ret;
+
+ printf("[RUN]\tprocess_vm_readv() from vsyscall page\n");
+
+ local.iov_base = buf;
+ local.iov_len = 4096;
+ remote.iov_base = (void *)0xffffffffff600000;
+ remote.iov_len = 4096;
+ ret = process_vm_readv(getpid(), &local, 1, &remote, 1, 0);
+ if (ret != 4096) {
+ printf("[OK]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", ret, errno);
+ return 0;
+ }
+
+ if (vsyscall_map_r) {
+ if (!memcmp(buf, (const void *)0xffffffffff600000, 4096)) {
+ printf("[OK]\tIt worked and read correct data\n");
+ } else {
+ printf("[FAIL]\tIt worked but returned incorrect data\n");
+ return 1;
+ }
+ }
+#endif
+
+ return 0;
+}
#ifdef __x86_64__
#define X86_EFLAGS_TF (1UL << 8)
@@ -455,7 +522,7 @@ static int test_emulation(void)
time_t tmp;
bool is_native;
- if (!vtime)
+ if (!vsyscall_map_x)
return 0;
printf("[RUN]\tchecking that vsyscalls are emulated\n");
@@ -497,6 +564,9 @@ int main(int argc, char **argv)
sethandler(SIGSEGV, sigsegv, 0);
nerrs += test_vsys_r();
+ nerrs += test_vsys_x();
+
+ nerrs += test_process_vm_readv();
#ifdef __x86_64__
nerrs += test_emulation();
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.