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Merge pull request #10764 from embhorn/gh10761

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Fix TLS1.2 error code correction
This commit is contained in:
Daniel Pouzzner
2026-07-03 00:41:35 -05:00
committed by GitHub
parent 0ecc0c5973 17523c69f6
commit 27e160fa53
2 changed files with 146 additions and 2 deletions
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src/tls13.c
+20 -2
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@@ -5538,8 +5538,26 @@ int DoTls13ServerHello(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
}
if ((args->idx - args->begin) + OPAQUE16_LEN > helloSz) {
if (!ssl->options.downgrade)
return BUFFER_ERROR;
if (!ssl->options.downgrade) {
/* Fewer than OPAQUE16_LEN bytes remain after the compression
* method, so there is no complete extensions length field. */
if ((args->idx - args->begin) < helloSz) {
/* A partial extensions length field is genuinely malformed:
* report it as a decode error. */
WOLFSSL_MSG("Truncated extensions length in ServerHello");
return BUFFER_ERROR;
}
/* No extensions field at all, so the server is not offering TLS 1.3
* (no supported_versions extension - see RFC 8446 4.2.1) but TLS 1.2
* or below. This is a well-formed message, so a TLS 1.3-only client
* (downgrade disabled) must reject it as a version mismatch, not as
* a malformed message. Returning VERSION_ERROR makes the caller send
* a protocol_version alert (RFC 8446 6.2) rather than decode_error. */
WOLFSSL_MSG("Server offered TLS 1.2 (no supported_versions ext) "
"but downgrade not allowed");
WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
return VERSION_ERROR;
}
#ifndef WOLFSSL_NO_TLS12
/* Force client hello version 1.2 to work for static RSA. */
ssl->chVersion.minor = TLSv1_2_MINOR;