Re: [PATCH] libsanitizer: fix SIGSEGV in fopen64 interceptor

[Martin Liška]

On 11/20/20 8:44 AM, Vyacheslav Barinov wrote:

Hello,

Okay, I proposed this check to upstream [1] and it has already been
accepted.

Hello.

Great. Please commit it to the llvm-project upstream and I'll make then
the patch cherry-pick.

We can either apply the fix or postpone it until next sync with
upstream.

Anyway the bug doesn't seem so bad if we were the only team who faced it during
all this time.

I see! But we still want to cherry-pick it.

Thanks,
Martin

Best Regards,
Vyacheslav Barinov

[1]: https://reviews.llvm.org/D91782

Martin Liška <mli...@suse.cz> writes:

On 11/19/20 12:28 PM, Slava Barinov via Gcc-patches wrote:

Null pointer in path argument leads to SIGSEGV in interceptor.

Hello.

I can't see we ever had the null check in master. I don't this it was lost
during a merge from master.

Why do we need the hunk?
Thanks,
Martin

libsanitizer/ChangeLog:
          * sanitizer_common/sanitizer_common_interceptors.inc: Check
        path for null before dereference in fopen64 interceptor.
---
Notes:
      Apparently check has been lost during merge from upstream
   libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc | 2 +-
   1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc
b/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc
index 729eead43c0..2ef23d9a50b 100644
--- a/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc
@@ -6081,7 +6081,7 @@ INTERCEPTOR(__sanitizer_FILE *, freopen, const char 
*path, const char *mode,
   INTERCEPTOR(__sanitizer_FILE *, fopen64, const char *path, const char *mode) 
{
     void *ctx;
     COMMON_INTERCEPTOR_ENTER(ctx, fopen64, path, mode);
-  COMMON_INTERCEPTOR_READ_RANGE(ctx, path, REAL(strlen)(path) + 1);
+  if (path) COMMON_INTERCEPTOR_READ_RANGE(ctx, path, REAL(strlen)(path) + 1);
     COMMON_INTERCEPTOR_READ_RANGE(ctx, mode, REAL(strlen)(mode) + 1);
     __sanitizer_FILE *res = REAL(fopen64)(path, mode);
     COMMON_INTERCEPTOR_FILE_OPEN(ctx, res, path);