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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-03-29 14:02:46 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-04-12 09:23:46 +0200 |
| commit | d0381c81c2f782fa2131178d11e0cfb23d50d631 (patch) | |
| tree | 501377d73c122209875f375a190634170cb073fe | |
| parent | 490154bc68d15de9e38fbb850fe470e32cc66407 (diff) | |
| download | linux-d0381c81c2f782fa2131178d11e0cfb23d50d631.tar.gz linux-d0381c81c2f782fa2131178d11e0cfb23d50d631.tar.bz2 linux-d0381c81c2f782fa2131178d11e0cfb23d50d631.zip | |
kprobes/x86: Set kprobes pages read-only
Set the pages which is used for kprobes' singlestep buffer
and optprobe's trampoline instruction buffer to readonly.
This can prevent unexpected (or unintended) instruction
modification.
This also passes rodata_test as below.
Without this patch, rodata_test shows a warning:
WARNING: CPU: 0 PID: 1 at arch/x86/mm/dump_pagetables.c:235 note_page+0x7a9/0xa20
x86/mm: Found insecure W+X mapping at address ffffffffa0000000/0xffffffffa0000000
With this fix, no W+X pages are found:
x86/mm: Checked W+X mappings: passed, no W+X pages found.
rodata_test: all tests were successful
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ye Xiaolong <xiaolong.ye@intel.com>
Link: http://lkml.kernel.org/r/149076375592.22469.14174394514338612247.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 3 |
2 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 3f084a0ca722..0dc24e6cdd1e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -419,6 +419,8 @@ static int arch_copy_kprobe(struct kprobe *p) { int len; + set_memory_rw((unsigned long)p->ainsn.insn & PAGE_MASK, 1); + /* Copy an instruction with recovering if other optprobe modifies it.*/ len = __copy_instruction(p->ainsn.insn, p->addr); if (!len) @@ -430,6 +432,8 @@ static int arch_copy_kprobe(struct kprobe *p) */ prepare_boost(p, len); + set_memory_ro((unsigned long)p->ainsn.insn & PAGE_MASK, 1); + /* Check whether the instruction modifies Interrupt Flag or not */ p->ainsn.if_modifier = is_IF_modifier(p->ainsn.insn); diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 3e7c6e5a08ff..b121037739e4 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -350,6 +350,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, } buf = (u8 *)op->optinsn.insn; + set_memory_rw((unsigned long)buf & PAGE_MASK, 1); /* Copy instructions into the out-of-line buffer */ ret = copy_optimized_instructions(buf + TMPL_END_IDX, op->kp.addr); @@ -372,6 +373,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, synthesize_reljump(buf + TMPL_END_IDX + op->optinsn.size, (u8 *)op->kp.addr + op->optinsn.size); + set_memory_ro((unsigned long)buf & PAGE_MASK, 1); + flush_icache_range((unsigned long) buf, (unsigned long) buf + TMPL_END_IDX + op->optinsn.size + RELATIVEJUMP_SIZE); |