[compiler-rt] b0fdbad - [ubsan] warn inside the sigaction interceptor if static linking is suspected, and continue instead of crashing on null deref

[Kostya Serebryany via llvm-commits]

Author: Kostya Serebryany
Date: 2021-09-01T12:36:48-07:00
New Revision: b0fdbadf9f099e42bd2185ed32211b2d73cb2f58

URL: https://github.com/llvm/llvm-project/commit/b0fdbadf9f099e42bd2185ed32211b2d73cb2f58
DIFF: https://github.com/llvm/llvm-project/commit/b0fdbadf9f099e42bd2185ed32211b2d73cb2f58.diff

LOG: [ubsan] warn inside the sigaction interceptor if static linking is suspected, and continue instead of crashing on null deref

[ubsan] warn inside the sigaction interceptor if static linking is suspected, and continue instead of crashing on null deref

Reviewed By: kostik

Differential Revision: https://reviews.llvm.org/D109081

Added: 
    compiler-rt/test/ubsan/TestCases/Misc/Linux/static-link.cpp

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_signal_interceptors.inc

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_signal_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_signal_interceptors.inc
index cefb870f7e258..475e577d9982e 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_signal_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_signal_interceptors.inc
@@ -29,8 +29,16 @@ using namespace __sanitizer;
 #endif
 
 #ifndef SIGNAL_INTERCEPTOR_SIGACTION_IMPL
-#define SIGNAL_INTERCEPTOR_SIGACTION_IMPL(signum, act, oldact) \
-  { return REAL(sigaction_symname)(signum, act, oldact); }
+#  define SIGNAL_INTERCEPTOR_SIGACTION_IMPL(signum, act, oldact)              \
+    {                                                                         \
+      if (!REAL(sigaction_symname)) {                                         \
+        Printf(                                                               \
+            "Warning: REAL(sigaction_symname) == nullptr. This may happen "   \
+            "if you link with ubsan statically. Sigaction will not work.\n"); \
+        return -1;                                                            \
+      }                                                                       \
+      return REAL(sigaction_symname)(signum, act, oldact);                    \
+    }
 #endif
 
 #if SANITIZER_INTERCEPT_BSD_SIGNAL

diff  --git a/compiler-rt/test/ubsan/TestCases/Misc/Linux/static-link.cpp b/compiler-rt/test/ubsan/TestCases/Misc/Linux/static-link.cpp
new file mode 100644
index 0000000000000..6c6b421e40c6a
--- /dev/null
+++ b/compiler-rt/test/ubsan/TestCases/Misc/Linux/static-link.cpp
@@ -0,0 +1,13 @@
+// REQUIRES: ubsan-standalone
+// REQUIRES: arch=x86_64
+// RUN: %clangxx -fsanitize=bool -static  %s -o %t && UBSAN_OPTIONS=handle_segv=0:handle_sigbus=0:handle_sigfpe=0 %run %t 2>&1 | FileCheck %s
+#include <signal.h>
+#include <stdio.h>
+
+int main() {
+  struct sigaction old_action;
+  sigaction(SIGINT, nullptr, &old_action);
+  // CHECK: Warning: REAL(sigaction_symname) == nullptr.
+  printf("PASS\n");
+  // CHECK: PASS
+}