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| author | Peter Zijlstra <peterz@infradead.org> | 2021-10-30 09:47:58 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-11-11 13:09:31 +0100 |
| commit | 2105a92748e83e2e3ee6be539da959706bbb3898 (patch) | |
| tree | 04dd3c3a9a55be81189d30054b015b2587dc5968 /arch/x86/include/asm | |
| parent | Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/t... (diff) | |
| download | linux-2105a92748e83e2e3ee6be539da959706bbb3898.tar.xz linux-2105a92748e83e2e3ee6be539da959706bbb3898.zip | |
static_call,x86: Robustify trampoline patching
Add a few signature bytes after the static call trampoline and verify
those bytes match before patching the trampoline. This avoids patching
random other JMPs (such as CFI jump-table entries) instead.
These bytes decode as:
d: 53 push %rbx
e: 43 54 rex.XB push %r12
And happen to spell "SCT".
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211030074758.GT174703@worktop.programming.kicks-ass.net
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/static_call.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/static_call.h b/arch/x86/include/asm/static_call.h index cbb67b6030f9..39ebe0511869 100644 --- a/arch/x86/include/asm/static_call.h +++ b/arch/x86/include/asm/static_call.h @@ -27,6 +27,7 @@ ".globl " STATIC_CALL_TRAMP_STR(name) " \n" \ STATIC_CALL_TRAMP_STR(name) ": \n" \ insns " \n" \ + ".byte 0x53, 0x43, 0x54 \n" \ ".type " STATIC_CALL_TRAMP_STR(name) ", @function \n" \ ".size " STATIC_CALL_TRAMP_STR(name) ", . - " STATIC_CALL_TRAMP_STR(name) " \n" \ ".popsection \n") |