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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-05-25 19:38:17 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-08 11:49:45 +0200 |
| commit | 502990185f76a3f3816e3c1e2c130001dc9923cb (patch) | |
| tree | 00876b6509d45fbb80dc32a72df07d79e39f073c | |
| parent | 2883c668105d7829aee746d12ce0407b22c345a4 (diff) | |
| download | linux-502990185f76a3f3816e3c1e2c130001dc9923cb.tar.gz linux-502990185f76a3f3816e3c1e2c130001dc9923cb.tar.bz2 linux-502990185f76a3f3816e3c1e2c130001dc9923cb.zip | |
kprobes/x86: Fix to set RWX bits correctly before releasing trampoline
commit c93f5cf571e7795f97d49ef51b766cf25e328545 upstream.
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>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 78f221ab8593..51947348fcb9 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -49,6 +49,7 @@ #include <linux/kdebug.h> #include <linux/kallsyms.h> #include <linux/ftrace.h> +#include <linux/moduleloader.h> #include <asm/cacheflush.h> #include <asm/desc.h> @@ -374,6 +375,14 @@ int __copy_instruction(u8 *dest, u8 *src) return length; } +/* 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); + vfree(page); +} + static int arch_copy_kprobe(struct kprobe *p) { int ret; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 0d2f0e7c7605..359d4de103b7 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -125,7 +125,7 @@ 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_free(NULL, page); } |