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Replace XMEMCMP with ConstantCompare when validating secure renegotiation (SCR) verify data #9899

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Merged
douzzer merged 2 commits into from
Mar 7, 2026
+9 −8
Merged

Replace XMEMCMP with ConstantCompare when validating secure renegotiation (SCR) verify data #9899

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1555ec4
Replace `XMEMCMP` with `ConstantCompare` when validating secure reneg…
julek-wolfssl Mar 6, 2026
479de5a
Always eval both ConstantCompare statements
julek-wolfssl Mar 6, 2026
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17 changes: 9 additions & 8 deletions src/tls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6047,7 +6047,7 @@ static int TLSX_SecureRenegotiation_Parse(WOLFSSL* ssl, const byte* input,
input++; /* get past size */

/* validate client verify data */
if (XMEMCMP(input,
if (ConstantCompare(input,
ssl->secure_renegotiation->client_verify_data,
TLS_FINISHED_SZ) == 0) {
WOLFSSL_MSG("SCR client verify data match");
Expand All @@ -6072,15 +6072,16 @@ static int TLSX_SecureRenegotiation_Parse(WOLFSSL* ssl, const byte* input,
}
else if (*input == 2 * TLS_FINISHED_SZ &&
length == 2 * TLS_FINISHED_SZ + OPAQUE8_LEN) {
int cmpRes = 0;
input++; /* get past size */

cmpRes |= ConstantCompare(input,
ssl->secure_renegotiation->client_verify_data,
TLS_FINISHED_SZ);
cmpRes |= ConstantCompare(input + TLS_FINISHED_SZ,
ssl->secure_renegotiation->server_verify_data,
TLS_FINISHED_SZ);
/* validate client and server verify data */
if (XMEMCMP(input,
ssl->secure_renegotiation->client_verify_data,
TLS_FINISHED_SZ) == 0 &&
XMEMCMP(input + TLS_FINISHED_SZ,
ssl->secure_renegotiation->server_verify_data,
TLS_FINISHED_SZ) == 0) {
if (cmpRes == 0) {
WOLFSSL_MSG("SCR client and server verify data match");
ret = 0; /* verified */
}
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