From 5dc8f91c186d88a74493c229c7afbf3eb40599a8 Mon Sep 17 00:00:00 2001 From: Vitaly Chikunov Date: Sun, 9 Jan 2022 02:25:31 +0300 Subject: [PATCH] gost_ec_keyx: Check CTX data before it's really used This should fix Coverity warning: *** CID 345243: Null pointer dereferences (REVERSE_INULL) /gost_ec_keyx.c: 681 in pkey_gost2018_decrypt() 675 o Q_eph is on the same curve as server public key; 676 677 o Q_eph is not equal to zero point; 678 679 o q * Q_eph is not equal to zero point. 680 */ >>> CID 345243: Null pointer dereferences (REVERSE_INULL) >>> Null-checking "data" suggests that it may be null, but it has already been dereferenced on all paths leading to the check. 681 if (eph_key == NULL || priv == NULL || data == NULL) { 682 GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT, 683 GOST_R_ERROR_COMPUTING_EXPORT_KEYS); 684 ret = 0; 685 goto err; 686 } Signed-off-by: Vitaly Chikunov Issue: #380 --- gost_ec_keyx.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/gost_ec_keyx.c b/gost_ec_keyx.c index 06835d3..944db40 100644 --- a/gost_ec_keyx.c +++ b/gost_ec_keyx.c @@ -630,16 +630,24 @@ static int pkey_gost2018_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key, size_t in_len) { const unsigned char *p = in; - struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx); - EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx); + struct gost_pmeth_data *data; + EVP_PKEY *priv; PSKeyTransport_gost *pst = NULL; int ret = 0; unsigned char expkeys[64]; EVP_PKEY *eph_key = NULL; - int pkey_nid = EVP_PKEY_base_id(priv); + int pkey_nid; int mac_nid = NID_undef; int iv_len = 0; + if (!(data = EVP_PKEY_CTX_get_data(pctx)) || + !(priv = EVP_PKEY_CTX_get0_pkey(pctx))) { + GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT, GOST_R_ERROR_COMPUTING_EXPORT_KEYS); + ret = 0; + goto err; + } + pkey_nid = EVP_PKEY_base_id(priv); + switch (data->cipher_nid) { case NID_magma_ctr: mac_nid = NID_magma_mac; @@ -678,7 +686,7 @@ static int pkey_gost2018_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key, o q * Q_eph is not equal to zero point. */ - if (eph_key == NULL || priv == NULL || data == NULL) { + if (eph_key == NULL) { GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT, GOST_R_ERROR_COMPUTING_EXPORT_KEYS); ret = 0; -- 2.39.5