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-rw-r--r--kernel/module.c101
1 files changed, 69 insertions, 32 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 646f1e2330d2..ef400c389f49 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4,6 +4,9 @@
Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
*/
+
+#define INCLUDE_VERMAGIC
+
#include <linux/export.h>
#include <linux/extable.h>
#include <linux/moduleloader.h>
@@ -1943,7 +1946,6 @@ static void mod_sysfs_teardown(struct module *mod)
mod_sysfs_fini(mod);
}
-#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
/*
* LKM RO/NX protection: protect module's text/ro-data
* from modification and any data from execution.
@@ -1957,6 +1959,14 @@ static void mod_sysfs_teardown(struct module *mod)
*
* These values are always page-aligned (as is base)
*/
+
+/*
+ * Since some arches are moving towards PAGE_KERNEL module allocations instead
+ * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the
+ * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of
+ * whether we are strict.
+ */
+#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
static void frob_text(const struct module_layout *layout,
int (*set_memory)(unsigned long start, int num_pages))
{
@@ -1966,6 +1976,15 @@ static void frob_text(const struct module_layout *layout,
layout->text_size >> PAGE_SHIFT);
}
+static void module_enable_x(const struct module *mod)
+{
+ frob_text(&mod->core_layout, set_memory_x);
+ frob_text(&mod->init_layout, set_memory_x);
+}
+#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
+static void module_enable_x(const struct module *mod) { }
+#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
+
#ifdef CONFIG_STRICT_MODULE_RWX
static void frob_rodata(const struct module_layout *layout,
int (*set_memory)(unsigned long start, int num_pages))
@@ -1997,20 +2016,7 @@ static void frob_writable_data(const struct module_layout *layout,
(layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
}
-/* livepatching wants to disable read-only so it can frob module. */
-void module_disable_ro(const struct module *mod)
-{
- if (!rodata_enabled)
- return;
-
- frob_text(&mod->core_layout, set_memory_rw);
- frob_rodata(&mod->core_layout, set_memory_rw);
- frob_ro_after_init(&mod->core_layout, set_memory_rw);
- frob_text(&mod->init_layout, set_memory_rw);
- frob_rodata(&mod->init_layout, set_memory_rw);
-}
-
-void module_enable_ro(const struct module *mod, bool after_init)
+static void module_enable_ro(const struct module *mod, bool after_init)
{
if (!rodata_enabled)
return;
@@ -2036,19 +2042,29 @@ static void module_enable_nx(const struct module *mod)
frob_writable_data(&mod->init_layout, set_memory_nx);
}
+static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
+ int i;
+
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if ((sechdrs[i].sh_flags & shf_wx) == shf_wx)
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+
#else /* !CONFIG_STRICT_MODULE_RWX */
static void module_enable_nx(const struct module *mod) { }
-#endif /* CONFIG_STRICT_MODULE_RWX */
-static void module_enable_x(const struct module *mod)
+static void module_enable_ro(const struct module *mod, bool after_init) {}
+static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
{
- frob_text(&mod->core_layout, set_memory_x);
- frob_text(&mod->init_layout, set_memory_x);
+ return 0;
}
-#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
-static void module_enable_nx(const struct module *mod) { }
-static void module_enable_x(const struct module *mod) { }
-#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
-
+#endif /* CONFIG_STRICT_MODULE_RWX */
#ifdef CONFIG_LIVEPATCH
/*
@@ -2334,11 +2350,13 @@ static int apply_relocations(struct module *mod, const struct load_info *info)
if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
continue;
- /* Livepatch relocation sections are applied by livepatch */
if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
- continue;
-
- if (info->sechdrs[i].sh_type == SHT_REL)
+ err = klp_apply_section_relocs(mod, info->sechdrs,
+ info->secstrings,
+ info->strtab,
+ info->index.sym, i,
+ NULL);
+ else if (info->sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(info->sechdrs, info->strtab,
info->index.sym, i, mod);
else if (info->sechdrs[i].sh_type == SHT_RELA)
@@ -2400,7 +2418,7 @@ static void layout_sections(struct module *mod, struct load_info *info)
if ((s->sh_flags & masks[m][0]) != masks[m][0]
|| (s->sh_flags & masks[m][1])
|| s->sh_entsize != ~0UL
- || strstarts(sname, ".init"))
+ || module_init_section(sname))
continue;
s->sh_entsize = get_offset(mod, &mod->core_layout.size, s, i);
pr_debug("\t%s\n", sname);
@@ -2433,7 +2451,7 @@ static void layout_sections(struct module *mod, struct load_info *info)
if ((s->sh_flags & masks[m][0]) != masks[m][0]
|| (s->sh_flags & masks[m][1])
|| s->sh_entsize != ~0UL
- || !strstarts(sname, ".init"))
+ || !module_init_section(sname))
continue;
s->sh_entsize = (get_offset(mod, &mod->init_layout.size, s, i)
| INIT_OFFSET_MASK);
@@ -2768,6 +2786,11 @@ void * __weak module_alloc(unsigned long size)
return vmalloc_exec(size);
}
+bool __weak module_init_section(const char *name)
+{
+ return strstarts(name, ".init");
+}
+
bool __weak module_exit_section(const char *name)
{
return strstarts(name, ".exit");
@@ -2946,8 +2969,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
return err;
/* Suck in entire file: we'll want most of it. */
- info->hdr = __vmalloc(info->len,
- GFP_KERNEL | __GFP_NOWARN, PAGE_KERNEL);
+ info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
if (!info->hdr)
return -ENOMEM;
@@ -3150,6 +3172,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
}
#endif
+ mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
+ &mod->noinstr_text_size);
+
#ifdef CONFIG_TRACEPOINTS
mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
sizeof(*mod->tracepoints_ptrs),
@@ -3194,6 +3219,13 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(*mod->ei_funcs),
&mod->num_ei_funcs);
#endif
+#ifdef CONFIG_KPROBES
+ mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
+ &mod->kprobes_text_size);
+ mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
+ sizeof(unsigned long),
+ &mod->num_kprobe_blacklist);
+#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
@@ -3378,6 +3410,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
if (err < 0)
return ERR_PTR(err);
+ err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
+ info->secstrings, info->mod);
+ if (err < 0)
+ return ERR_PTR(err);
+
/* We will do a special allocation for per-cpu sections later. */
info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.