diff options
| author | Ivan Krasin <krasin@chromium.org> | 2016-06-02 18:36:12 +0000 |
|---|---|---|
| committer | Ivan Krasin <krasin@chromium.org> | 2016-06-02 18:36:12 +0000 |
| commit | 4deefb03523c51ca2eba3fabff692a47f24e1bfa (patch) | |
| tree | e50a8e561e9ffb94226b6a69ab4cfa88b63b0bb3 /lib/ubsan/ubsan_type_hash.h | |
| parent | e151fbe8a11f85f4b0577ab3d27ef5254c3c4f74 (diff) | |
UBSan: crash less often on corrupted Vtables.
Summary:
This CL adds a weak check for a Vtable prefix: for a well-formed
Vtable, we require the prefix to be within [-1<<20; 1<<20].
Practically, this solves most of the known cases when UBSan segfaults
without providing any useful diagnostics.
Reviewers: pcc
Subscribers: kubabrecka
Differential Revision: http://reviews.llvm.org/D19750
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@271560 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/ubsan/ubsan_type_hash.h')
| -rw-r--r-- | lib/ubsan/ubsan_type_hash.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/ubsan/ubsan_type_hash.h b/lib/ubsan/ubsan_type_hash.h index 695fed905..aa638713f 100644 --- a/lib/ubsan/ubsan_type_hash.h +++ b/lib/ubsan/ubsan_type_hash.h @@ -53,6 +53,10 @@ bool checkDynamicType(void *Object, void *Type, HashValue Hash); const unsigned VptrTypeCacheSize = 128; +/// A sanity check for Vtable. Offsets to top must be reasonably small +/// numbers (by absolute value). It's a weak check for Vtable corruption. +const int VptrMaxOffsetToTop = 1<<20; + /// \brief A cache of the results of checkDynamicType. \c checkDynamicType would /// return \c true (modulo hash collisions) if /// \code |