Strip sa_handler if ptrauth_calls is present#7
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jchlanda wants to merge 1 commit intoaccess-softek:v1.2.5-pauth-rev2025-11-21from
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Strip sa_handler if ptrauth_calls is present#7jchlanda wants to merge 1 commit intoaccess-softek:v1.2.5-pauth-rev2025-11-21from
jchlanda wants to merge 1 commit intoaccess-softek:v1.2.5-pauth-rev2025-11-21from
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This follows the same logic as for the restorer. Without stripping kernel would receive a signed address and use it, as is, to call the signal handler, which would result in an invalid memory access. For the record, this was spotted when running Rust signal handler as registered here (`fn init()`): https://github.com/rust-lang/rust/blob/main/library/std/src/sys/pal/unix/stack_overflow.rs#L184 Sample strace output showing invalid (signed) pointer: ``` rt_sigaction(SIGSEGV, {sa_handler=0x13f96bba92acf8, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_SIGINFO, sa_restorer=0xf96bbaad0430}, NULL, 8) = 0 ```
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Thanks! Let me ensure that llvm-test-suite and pauth-testsuite continue passing with this patch applied before giving the final approval |
asl
reviewed
Mar 13, 2026
| } | ||
| ksa.handler = sa->sa_handler; | ||
| #if __has_feature(ptrauth_calls) | ||
| ksa.handler = __builtin_ptrauth_strip(ksa.handler, 0); |
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Don't we want to authenticate the pointer value instead of merely striping here and in similar places? @kovdan01
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Strip sa_handler if ptrauth_calls is present
This follows the same logic as for the restorer. Without stripping
kernel would receive a signed address and use it, as is, to call the
signal handler, which would result in an invalid memory access.
For the record, this was spotted when running Rust signal handler as
registered here (
fn init()):https://github.com/rust-lang/rust/blob/main/library/std/src/sys/pal/unix/stack_overflow.rs#L184
Sample strace output showing invalid (signed) pointer: