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Fix off by ones when parsing XML comments #17
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This commit fixes off by ones when parsing XML comments. The `strncmp` calls before this commit: strncmp(cursor, "<!--", 3) would also incorrectly match shorter strings such as "<!-". Depending on the use-cases this might or might not be vulnerabilities. Depending on the use, this issue could be a security bug/risk for the callers of this library, e.g. if two different XML parsing libraries would be used for e.g. validating and then executing some rules. I would even say this could cause bugs similar to https://twitter.com/s1guza/status/1255641164885131268 to happen. This issue was first reported to Google via https://www.google.com/appserve/security-bugs/ but I was replied with "We think the issue might not be severe enough for us to track it as a security bug", so I am sending a fix here.
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This commit fixes off by ones when parsing XML comments.
The
strncmpcalls before this commit: strncmp(cursor, "<!--", 3) would also incorrectly match shorter strings such as "<!-". Depending on the use-cases this might or might not be vulnerabilities.This could be a security bug/risk for the
callers of this library, e.g. if two different XML parsing libraries
would be used, e.g., for validating and then executing some policies. I would
even say this could cause bugs similar to
https://twitter.com/s1guza/status/1255641164885131268 to happen.
This issue was first reported to Google on Apr 13, 2020 via
https://www.google.com/appserve/security-bugs/ but I was replied with
"We think the issue might not be severe enough for us to track it as a
security bug", so I am sending a fix here.