Commit b46984e9 authored by
Fix out-of-bound memory read in `tor_tls_cert_matches_key()` for NSS.
This patch fixes an out-of-bound memory read in `tor_tls_cert_matches_key()` when Tor is compiled to use Mozilla's NSS instead of OpenSSL. The NSS library stores some length fields in bits instead of bytes, but the comparison function found in `SECITEM_ItemsAreEqual()` needs the length to be encoded in bytes. This means that for a 140-byte, DER-encoded, SubjectPublicKeyInfo struct (with a 1024-bit RSA public key in it), we would ask `SECITEM_ItemsAreEqual()` to compare the first 1120 bytes instead of 140 (140bytes * 8bits = 1120bits). This patch fixes the issue by converting from bits to bytes before calling `SECITEM_ItemsAreEqual()` and convert the `len`-fields back to bits before we leave the function. This patch is part of the fix for TROVE-2020-001. See: https://bugs.torproject.org/33119
Showing with 36 additions and 6 deletions