This is a note to let you know that I've just added the patch titled
kprobes/x86: Return correct length in __copy_instruction()
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kprobes-x86-return-correct-length-in-__copy_instruction.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd Mon Sep 17 00:00:00 2001
From: Eugene Shatokhin <eugene.shatokhin@xxxxxxxxxx>
Date: Tue, 17 Mar 2015 19:09:18 +0900
Subject: kprobes/x86: Return correct length in __copy_instruction()
From: Eugene Shatokhin <eugene.shatokhin@xxxxxxxxxx>
commit c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd upstream.
On x86-64, __copy_instruction() always returns 0 (error) if the
instruction uses %rip-relative addressing. This is because
kernel_insn_init() is called the second time for 'insn' instance
in such cases and sets all its fields to 0.
Because of this, trying to place a kprobe on such instruction
will fail, register_kprobe() will return -EINVAL.
This patch fixes the problem.
Signed-off-by: Eugene Shatokhin <eugene.shatokhin@xxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -326,13 +326,16 @@ int __kprobes __copy_instruction(u8 *des
{
struct insn insn;
kprobe_opcode_t buf[MAX_INSN_SIZE];
+ int length;
kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, (unsigned long)src));
insn_get_length(&insn);
+ length = insn.length;
+
/* Another subsystem puts a breakpoint, failed to recover */
if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
return 0;
- memcpy(dest, insn.kaddr, insn.length);
+ memcpy(dest, insn.kaddr, length);
#ifdef CONFIG_X86_64
if (insn_rip_relative(&insn)) {
@@ -362,7 +365,7 @@ int __kprobes __copy_instruction(u8 *des
*(s32 *) disp = (s32) newdisp;
}
#endif
- return insn.length;
+ return length;
}
static int __kprobes arch_copy_kprobe(struct kprobe *p)
Patches currently in stable-queue which might be from eugene.shatokhin@xxxxxxxxxx are
queue-3.14/kprobes-x86-return-correct-length-in-__copy_instruction.patch
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