diff options
author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-03-29 14:00:25 +0900 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-11 16:03:47 +0200 |
commit | 5ac07564b47fdffbc293f9b129eb5af394b3d31f (patch) | |
tree | 4c5c1a644ba93dd9f331443f045101dd93bfc54e | |
parent | 21e9341ed96024aaead1a12c77e9869ad81f8b96 (diff) |
kprobes/x86: Do not modify singlestep buffer while resuming
commit 804dec5bda9b4fcdab5f67fe61db4a0498af5221 upstream.
Do not modify singlestep execution buffer (kprobe.ainsn.insn)
while resuming from single-stepping, instead, modifies
the buffer to add a jump back instruction at preparing
buffer.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.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/149076361560.22469.1610155860343077495.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | arch/x86/kernel/kprobes/core.c | 42 |
1 files changed, 20 insertions, 22 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index df9be5b91270..1f5c47a49e35 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -411,25 +411,38 @@ void free_insn_page(void *page) module_memfree(page); } +/* Prepare reljump right after instruction to boost */ +static void prepare_boost(struct kprobe *p, int length) +{ + if (can_boost(p->ainsn.insn, p->addr) && + MAX_INSN_SIZE - length >= RELATIVEJUMP_SIZE) { + /* + * These instructions can be executed directly if it + * jumps back to correct address. + */ + synthesize_reljump(p->ainsn.insn + length, p->addr + length); + p->ainsn.boostable = 1; + } else { + p->ainsn.boostable = -1; + } +} + static int arch_copy_kprobe(struct kprobe *p) { - int ret; + int len; set_memory_rw((unsigned long)p->ainsn.insn & PAGE_MASK, 1); /* Copy an instruction with recovering if other optprobe modifies it.*/ - ret = __copy_instruction(p->ainsn.insn, p->addr); - if (!ret) + len = __copy_instruction(p->ainsn.insn, p->addr); + if (!len) return -EINVAL; /* * __copy_instruction can modify the displacement of the instruction, * but it doesn't affect boostable check. */ - if (can_boost(p->ainsn.insn, p->addr)) - p->ainsn.boostable = 0; - else - p->ainsn.boostable = -1; + prepare_boost(p, len); set_memory_ro((unsigned long)p->ainsn.insn & PAGE_MASK, 1); @@ -894,21 +907,6 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs, break; } - if (p->ainsn.boostable == 0) { - if ((regs->ip > copy_ip) && - (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) { - /* - * These instructions can be executed directly if it - * jumps back to correct address. - */ - synthesize_reljump((void *)regs->ip, - (void *)orig_ip + (regs->ip - copy_ip)); - p->ainsn.boostable = 1; - } else { - p->ainsn.boostable = -1; - } - } - regs->ip += orig_ip - copy_ip; no_change: |