[PATCH] D33911: [ubsan] Detect invalid unsigned pointer index expression (compiler-rt)
Vedant Kumar via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 5 12:57:50 PDT 2017
vsk created this revision.
Herald added subscribers: dberris, kubamracek.
Compiler-rt part of: https://reviews.llvm.org/D33910
https://reviews.llvm.org/D33911
Files:
lib/ubsan/ubsan_handlers.cc
test/ubsan/TestCases/Pointer/unsigned-index-expression.cpp
Index: test/ubsan/TestCases/Pointer/unsigned-index-expression.cpp
===================================================================
--- /dev/null
+++ test/ubsan/TestCases/Pointer/unsigned-index-expression.cpp
@@ -0,0 +1,12 @@
+// RUN: %clangxx -fsanitize=pointer-overflow %s -o %t
+// RUN: %t 2>&1 | FileCheck %s
+
+int main(int argc, char *argv[]) {
+ unsigned long long offset = -1;
+ char *p = (char *)7;
+
+ // CHECK: runtime error: unsigned pointer index expression result is 0x{{0+}}6, preceding its base 0x{{0+}}7
+ char *q = p + offset;
+
+ return 0;
+}
Index: lib/ubsan/ubsan_handlers.cc
===================================================================
--- lib/ubsan/ubsan_handlers.cc
+++ lib/ubsan/ubsan_handlers.cc
@@ -566,8 +566,14 @@
ScopedReport R(Opts, Loc, ET);
- Diag(Loc, DL_Error, "pointer index expression with base %0 overflowed to %1")
- << (void *)Base << (void*)Result;
+ if ((sptr(Base) > 0) == (sptr(Result) > 0))
+ Diag(Loc, DL_Error, "unsigned pointer index expression result is %0, "
+ "preceding its base %1")
+ << (void *)Result << (void *)Base;
+ else
+ Diag(Loc, DL_Error,
+ "pointer index expression with base %0 overflowed to %1")
+ << (void *)Base << (void *)Result;
}
void __ubsan::__ubsan_handle_pointer_overflow(PointerOverflowData *Data,
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