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| author | Nick Mathewson <nickm@torproject.org> | 2015-10-21 11:44:43 -0400 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2015-10-21 11:44:43 -0400 |
| commit | 35bf07b8d67d018f7740ca195cf8c7c86b1b4ef9 (patch) | |
| tree | 96ab072a93a2d30f4723383607a5169f35d1546c | |
| parent | 62b02a1941c6c51efe36f804ddd10f62a3606d41 (diff) | |
| download | tor-35bf07b8d67d018f7740ca195cf8c7c86b1b4ef9.tar.gz tor-35bf07b8d67d018f7740ca195cf8c7c86b1b4ef9.zip | |
Check for len < 4 in dn_indicates_v3_cert
Without this check, we potentially look up to 3 characters before
the start of a malloc'd segment, which could provoke a crash under
certain (weird afaik) circumstances.
Fixes 17404; bugfix on 0.2.6.3-alpha.
| -rw-r--r-- | changes/bug17404 | 6 | ||||
| -rw-r--r-- | src/common/tortls.c | 4 |
2 files changed, 10 insertions, 0 deletions
diff --git a/changes/bug17404 b/changes/bug17404 new file mode 100644 index 0000000000..d524f6662d --- /dev/null +++ b/changes/bug17404 @@ -0,0 +1,6 @@ + o Major bugfixes (security, correctness): + - Fix a programming error that could cause us to read 4 bytes before + the beginning of an openssl string. This could be used to provoke + a crash on systems with an unusual malloc implementation, or + systems with unsual hardening installed. Fixes bug 17404; bugfix + on 0.2.3.6-alpha. diff --git a/src/common/tortls.c b/src/common/tortls.c index 4222f6dbff..75ca47dbdb 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -2676,6 +2676,10 @@ dn_indicates_v3_cert(X509_NAME *name) len = ASN1_STRING_to_UTF8(&s, str); if (len < 0) return 0; + if (len < 4) { + OPENSSL_free(s); + return 0; + } r = fast_memneq(s + len - 4, ".net", 4); OPENSSL_free(s); return r; |