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Diffstat (limited to 'arch/x86/kernel/kprobes/core.c')
-rw-r--r--arch/x86/kernel/kprobes/core.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fed46ddb1eef..cf52ee0d8711 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -431,8 +431,21 @@ void *alloc_insn_page(void)
void *page;
page = module_alloc(PAGE_SIZE);
- if (page)
- set_memory_ro((unsigned long)page & PAGE_MASK, 1);
+ if (!page)
+ return NULL;
+
+ set_vm_flush_reset_perms(page);
+ /*
+ * First make the page read-only, and only then make it executable to
+ * prevent it from being W+X in between.
+ */
+ set_memory_ro((unsigned long)page, 1);
+
+ /*
+ * TODO: Once additional kernel code protection mechanisms are set, ensure
+ * that the page was not maliciously altered and it is still zeroed.
+ */
+ set_memory_x((unsigned long)page, 1);
return page;
}
@@ -440,8 +453,6 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- set_memory_nx((unsigned long)page & PAGE_MASK, 1);
- set_memory_rw((unsigned long)page & PAGE_MASK, 1);
module_memfree(page);
}
@@ -716,6 +727,7 @@ NOKPROBE_SYMBOL(kprobe_int3_handler);
* calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
asm(
+ ".text\n"
".global kretprobe_trampoline\n"
".type kretprobe_trampoline, @function\n"
"kretprobe_trampoline:\n"