diff options
| author | Eugene Shatokhin <eugene.shatokhin@rosalab.ru> | 2015-03-17 19:09:18 +0900 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2015-05-28 09:59:56 +0100 |
| commit | 4b01a53c364a5ebbe8976d0376a2bcbdb8daf9ab (patch) | |
| tree | 42745c0c47e0444b098c8010e3e44a361424b945 | |
| parent | 5de413904bcdaecff62ef4953bec2da8d21341e8 (diff) | |
kprobes/x86: Return correct length in __copy_instruction()
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@rosalab.ru>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ luis: backported to 3.16: used Eugene's backport for 3.16.y-3.18.y ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 93d2c04c6f8f..f2e281cf8c19 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -330,13 +330,16 @@ int __copy_instruction(u8 *dest, u8 *src) { 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)) { @@ -366,7 +369,7 @@ int __copy_instruction(u8 *dest, u8 *src) *(s32 *) disp = (s32) newdisp; } #endif - return insn.length; + return length; } static int arch_copy_kprobe(struct kprobe *p) |