Backport 3.6: Fix off-by-one over-read in TLS 1.2 ClientHello and CertificateRequest - #10928
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Backport 3.6: Fix off-by-one over-read in TLS 1.2 ClientHello and CertificateRequest#10928nvxbug wants to merge 3 commits into
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Signed-off-by: Naveed <naveed@bugqore.com>
ClientHello: narrow the session-id check to the session id itself, check the cookie length byte before reading it, and let the ciphersuite-list length check cover both transports. CertificateRequest: make the signature-algorithms check also reserve the two certificate-authorities length bytes instead of adding a separate check, use the available < needed pattern throughout, and reject an odd-length signature-algorithms list. Add injected truncated-ClientHello test cases (TLS 1.2-only builds). Signed-off-by: Naveed <naveed@bugqore.com>
Signed-off-by: Naveed <naveed@bugqore.com>
This was referenced Aug 24, 2026
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Description
Backport of #10833 to mbedtls-3.6.
The TLS 1.2 ClientHello and CertificateRequest parsers read a two-byte length field (ciphersuite list on the server side, certificate authorities on the client side) that the preceding length checks did not fully reserve, so a message truncated inside that field was read one byte past its end. The checks now use the
available < neededpattern, each field is checked before it is read, and an odd-length signature-algorithms list is rejected.Both commits cherry-picked from development; only the new test entries'
depends_onlines needed converting to the 3.6 macro names. The injected truncated-ClientHello tests pass in a TLS 1.2-only build (test_suite_ssl.tls-defrag 30/30).PR checklist