diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-05-25 19:38:17 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-05-26 22:37:00 -0400 |
| commit | c93f5cf571e7795f97d49ef51b766cf25e328545 (patch) | |
| tree | dbe64f0e9bf5a26ece23376aa925a8c13be817fe | |
| parent | f9797c2f20c0160edd718aa467101f3301e57e59 (diff) | |
kprobes/x86: Fix to set RWX bits correctly before releasing trampoline
Fix kprobes to set(recover) RWX bits correctly on trampoline
buffer before releasing it. Releasing readonly page to
module_memfree() crash the kernel.
Without this fix, if kprobes user register a bunch of kprobes
in function body (since kprobes on function entry usually
use ftrace) and unregister it, kernel hits a BUG and crash.
Link: http://lkml.kernel.org/r/149570868652.3518.14120169373590420503.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: d0381c81c2f7 ("kprobes/x86: Set kprobes pages read-only")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 9 | ||||
| -rw-r--r-- | kernel/kprobes.c | 2 |
2 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 5b2bbfbb3712..6b877807598b 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -52,6 +52,7 @@ #include <linux/ftrace.h> #include <linux/frame.h> #include <linux/kasan.h> +#include <linux/moduleloader.h> #include <asm/text-patching.h> #include <asm/cacheflush.h> @@ -417,6 +418,14 @@ static void prepare_boost(struct kprobe *p, struct insn *insn) } } +/* 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); +} + static int arch_copy_kprobe(struct kprobe *p) { struct insn insn; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 2d2d3a568e4e..adfe3b4cfe05 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -122,7 +122,7 @@ static void *alloc_insn_page(void) return module_alloc(PAGE_SIZE); } -static void free_insn_page(void *page) +void __weak free_insn_page(void *page) { module_memfree(page); } |