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authorGravatar Abseil Team <absl-team@google.com>2023-01-23 09:10:24 -0800
committerGravatar Copybara-Service <copybara-worker@google.com>2023-01-23 09:11:40 -0800
commit96355f50aa468b2ffc04589ea2b8573619ab205c (patch)
tree420336629ffde6819f546362353423bcf9bd2323 /absl/debugging
parent7e8d8018f621e94182876535320718542a4c5f09 (diff)
absl: harden stack bounds check
Ensure that we know both real low and high stack bounds when relying on the stack bounds check. PiperOrigin-RevId: 504003431 Change-Id: I8f6e6b75f5edff233d3cf80285f81b53f9080a0f
Diffstat (limited to 'absl/debugging')
-rw-r--r--absl/debugging/internal/stacktrace_x86-inl.inc20
1 files changed, 14 insertions, 6 deletions
diff --git a/absl/debugging/internal/stacktrace_x86-inl.inc b/absl/debugging/internal/stacktrace_x86-inl.inc
index ada2628d..7b26464e 100644
--- a/absl/debugging/internal/stacktrace_x86-inl.inc
+++ b/absl/debugging/internal/stacktrace_x86-inl.inc
@@ -267,12 +267,20 @@ static void **NextStackFrame(void **old_fp, const void *uc,
// guessed frame pointers incorrectly and now risk a paging fault
// dereferencing a wrong frame pointer. Or maybe not because large frames
// are possible as well. The main stack is assumed to be readable,
- // so we assume the large frame is legit if we know the stack bounds and are
- // within the stack.
- if (new_fp_u - old_fp_u > kMaxFrameBytes &&
- (stack_high == kUnknownStackEnd ||
- !(stack_low < new_fp_u && new_fp_u <= stack_high))) {
- return nullptr;
+ // so we assume the large frame is legit if we know the real stack bounds
+ // and are within the stack.
+ if (new_fp_u - old_fp_u > kMaxFrameBytes) {
+ if (stack_high < kUnknownStackEnd &&
+ static_cast<size_t>(getpagesize()) < stack_low) {
+ // Stack bounds are known.
+ if (!(stack_low < new_fp_u && new_fp_u <= stack_high)) {
+ // new_fp_u is not within the known stack.
+ return nullptr;
+ }
+ } else {
+ // Stack bounds are unknown, prefer truncated stack to possible crash.
+ return nullptr;
+ }
}
if (stack_low < old_fp_u && old_fp_u <= stack_high) {
// Old BP was in the expected stack region...