From 4a56d9a2ed306ad28946894eb73a3e504910e1c9 Mon Sep 17 00:00:00 2001 From: "Serguei E. Leontiev" Date: Sun, 11 May 2014 19:46:42 +0100 Subject: [PATCH] Replace manual ASN1 decoder with ASN1_get_object Replace manual ASN.1 decoder with ASN1_get object. This will decode the tag and length properly and check against it does not exceed the supplied buffer length. PR#3335 --- ssl/s3_srvr.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c index 9434923d0d..63ede49479 100644 --- a/ssl/s3_srvr.c +++ b/ssl/s3_srvr.c @@ -2979,6 +2979,8 @@ int ssl3_get_client_key_exchange(SSL *s) unsigned char premaster_secret[32], *start; size_t outlen=32, inlen; unsigned long alg_a; + int Ttag, Tclass; + long Tlen; /* Get our certificate private key*/ alg_a = s->s3->tmp.new_cipher->algorithm_auth; @@ -3000,26 +3002,15 @@ int ssl3_get_client_key_exchange(SSL *s) ERR_clear_error(); } /* Decrypt session key */ - if ((*p!=( V_ASN1_SEQUENCE| V_ASN1_CONSTRUCTED))) - { - SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_DECRYPTION_FAILED); - goto gerr; - } - if (p[1] == 0x81) - { - start = p+3; - inlen = p[2]; - } - else if (p[1] < 0x80) - { - start = p+2; - inlen = p[1]; - } - else + if (ASN1_get_object((const unsigned char **)&p, &Tlen, &Ttag, &Tclass, n) != V_ASN1_CONSTRUCTED || + Ttag != V_ASN1_SEQUENCE || + Tclass != V_ASN1_UNIVERSAL) { SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_DECRYPTION_FAILED); goto gerr; } + start = p; + inlen = Tlen; if (EVP_PKEY_decrypt(pkey_ctx,premaster_secret,&outlen,start,inlen) <=0) { -- 2.25.1