oss-sec mailing list archives
Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz
From: Matthew Fernandez <matthew.fernandez () gmail com>
Date: Tue, 25 Jun 2019 07:14:52 -0700
On Jun 25, 2019, at 06:41, Bob Friesenhahn <bfriesen () simple dallas tx us> wrote: * Consumption of uninitialized data (e.g. image data) which is not used to make important decisions. This is usually due to unhandled cases or error handling which does not quit immediately.
C/C++ compilers will infer backwards from uninitialized variable reads (undefined behavior in these languages) that preceding code is unreachable. For example, when moving from GCC 6 series to GCC 7 series we found one of our code bases would produce a binary that would only segfault when compiled at >= -O2. We root caused this to exactly the situation you describe: an error handling path that read uninitialized variables. The compiler appeared to infer backwards that the error check itself was a no-op as the true branch led to unconditional UB (this is my interpretation of its actions; I did not delve into the compiler’s internals). I’m probably telling you things you already know and it sounds like you don’t consider such issues worth addressing, but I just wanted to point out that these are not theoretical. These cause real problems for users and, for open source software, you may not have full control over what toolchain/flags users build your code with.
Current thread:
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz, (continued)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Stuart D. Gathman (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Bob Friesenhahn (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Matthew Fernandez (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz David A. Wheeler (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Simon McVittie (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Alex Gaynor (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Seth Arnold (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Bob Friesenhahn (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Alex Gaynor (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Alexander Potapenko (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Matthew Fernandez (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Jeff Law (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Pascal Cuoq (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Jeff Law (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Bob Friesenhahn (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Jeffrey Walton (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Florian Weimer (Jun 25)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Martin Carpenter (Jun 26)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Alexander Potapenko (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz Bob Friesenhahn (Jun 24)
- Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz John Haxby (Jun 24)