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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 11:51:56 +0200 |
| commit | dd26ec7f47749633439d0a623299a04de5e63bca (patch) | |
| tree | 4afef8a93d7bad32a5905010bc8c1c7e014db203 /arch | |
| parent | 51748a86dd5dc5ef789acf9e5522fe7ffc417d41 (diff) | |
| download | linux-stable-dd26ec7f47749633439d0a623299a04de5e63bca.tar.gz linux-stable-dd26ec7f47749633439d0a623299a04de5e63bca.tar.bz2 linux-stable-dd26ec7f47749633439d0a623299a04de5e63bca.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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 565e24e9ddf2..df9be5b91270 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> @@ -402,6 +403,14 @@ 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); + module_memfree(page); +} + static int arch_copy_kprobe(struct kprobe *p) { int ret; |