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Non-constant-time password hash comparison 

In wolfSSHd, the comparisons of the password hash and public keys were
using memcmp(). Changed to use ConstantCompare().

Affected functions: CheckPasswordHashUnix, CheckPublicKeyUnix.
Issue: F-53
pull/892/head
John Safranek 2026-03-09 10:13:29 -07:00
parent 010380666e
commit 801ac0701d
1 changed files with 3 additions and 2 deletions
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5
apps/wolfsshd/auth.c
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@ -338,7 +338,8 @@ static int CheckPasswordHashUnix(const char* input, char* stored)
if (storedSz == 0 || stored[0] == '*' ||
hashedInputSz == 0 || hashedInput[0] == '*' ||
hashedInputSz != storedSz ||
WMEMCMP(hashedInput, stored, storedSz) != 0) {
ConstantCompare((const byte*)hashedInput,
(const byte*)stored, storedSz) != 0) {
ret = WSSHD_AUTH_FAILURE;
}
}
@ -656,7 +657,7 @@ static int CheckPublicKeyUnix(const char* name,
if (rc == WS_SUCCESS) {
rc = wc_Hash(WC_HASH_TYPE_SHA256, caKey, caKeySz, fingerprint,
WC_SHA256_DIGEST_SIZE);
if (rc == 0 && WMEMCMP(fingerprint, pubKeyCtx->caKey,
if (rc == 0 && ConstantCompare(fingerprint, pubKeyCtx->caKey,
WC_SHA256_DIGEST_SIZE) == 0) {
foundKey = 1;
break;