From b213966415c35bafba6876127eecc9157077f81e Mon Sep 17 00:00:00 2001 From: "Mark J. Cox" Date: Thu, 28 Sep 2006 11:53:51 +0000 Subject: [PATCH] Introduce limits to prevent malicious keys being able to cause a denial of service. (CVE-2006-2940) [Steve Henson, Bodo Moeller] Fix ASN.1 parsing of certain invalid structures that can result in a denial of service. (CVE-2006-2937) [Steve Henson] Fix buffer overflow in SSL_get_shared_ciphers() function. (CVE-2006-3738) [Tavis Ormandy and Will Drewry, Google Security Team] Fix SSL client code which could crash if connecting to a malicious SSLv2 server. (CVE-2006-4343) [Tavis Ormandy and Will Drewry, Google Security Team] --- CHANGES | 14 ++++++++++++++ NEWS | 5 +++++ crypto/asn1/tasn_dec.c | 1 + crypto/dh/dh.h | 5 +++++ crypto/dh/dh_err.c | 1 + crypto/dh/dh_key.c | 6 ++++++ crypto/dsa/dsa.h | 6 ++++++ crypto/dsa/dsa_err.c | 2 ++ crypto/dsa/dsa_ossl.c | 12 ++++++++++++ crypto/rsa/rsa.h | 12 ++++++++++++ crypto/rsa/rsa_eay.c | 44 ++++++++++++++++++++++++++++++++++++++++++ crypto/rsa/rsa_err.c | 1 + ssl/s2_clnt.c | 3 ++- ssl/s3_srvr.c | 2 +- ssl/ssl_lib.c | 2 +- 15 files changed, 113 insertions(+), 3 deletions(-) diff --git a/CHANGES b/CHANGES index 6ece190c10..6a6c30a28a 100644 --- a/CHANGES +++ b/CHANGES @@ -4,6 +4,20 @@ Changes between 0.9.7k and 0.9.7l [xx XXX xxxx] + *) Introduce limits to prevent malicious keys being able to + cause a denial of service. (CVE-2006-2940) + [Steve Henson, Bodo Moeller] + + *) Fix ASN.1 parsing of certain invalid structures that can result + in a denial of service. (CVE-2006-2937) [Steve Henson] + + *) Fix buffer overflow in SSL_get_shared_ciphers() function. + (CVE-2006-3738) [Tavis Ormandy and Will Drewry, Google Security Team] + + *) Fix SSL client code which could crash if connecting to a + malicious SSLv2 server. (CVE-2006-4343) + [Tavis Ormandy and Will Drewry, Google Security Team] + *) Change ciphersuite string processing so that an explicit ciphersuite selects this one ciphersuite (so that "AES256-SHA" will no longer include "AES128-SHA"), and any other similar diff --git a/NEWS b/NEWS index 818ffde0ac..bd3ed1fdd1 100644 --- a/NEWS +++ b/NEWS @@ -5,6 +5,11 @@ This file gives a brief overview of the major changes between each OpenSSL release. For more details please read the CHANGES file. + Major changes between OpenSSL 0.9.7k and OpenSSL 0.9.7l: + + o Introduce limits to prevent malicious key DoS (CVE-2006-2940) + o Fix security issues (CVE-2006-2937, CVE-2006-3737, CVE-2006-4343) + Major changes between OpenSSL 0.9.7j and OpenSSL 0.9.7k: o Fix Daniel Bleichenbacher forged signature attack, CVE-2006-4339 diff --git a/crypto/asn1/tasn_dec.c b/crypto/asn1/tasn_dec.c index e5d5e4bfd1..fb7caa3f2c 100644 --- a/crypto/asn1/tasn_dec.c +++ b/crypto/asn1/tasn_dec.c @@ -629,6 +629,7 @@ static int asn1_d2i_ex_primitive(ASN1_VALUE **pval, unsigned char **in, long inl ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR); return 0; } else if(ret == -1) return -1; + ret = 0; /* SEQUENCE, SET and "OTHER" are left in encoded form */ if((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER)) { /* Clear context cache for type OTHER because the auto clear when diff --git a/crypto/dh/dh.h b/crypto/dh/dh.h index 92c7481e10..fe47553112 100644 --- a/crypto/dh/dh.h +++ b/crypto/dh/dh.h @@ -70,6 +70,10 @@ #include #include +#ifndef OPENSSL_DH_MAX_MODULUS_BITS +# define OPENSSL_DH_MAX_MODULUS_BITS 10000 +#endif + #define DH_FLAG_CACHE_MONT_P 0x01 #define DH_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DH * implementation now uses constant time @@ -207,6 +211,7 @@ void ERR_load_DH_strings(void); /* Reason codes. */ #define DH_R_BAD_GENERATOR 101 #define DH_R_NO_PRIVATE_VALUE 100 +#define DH_R_MODULUS_TOO_LARGE 103 #ifdef __cplusplus } diff --git a/crypto/dh/dh_err.c b/crypto/dh/dh_err.c index 83ccb41221..eb3d43104d 100644 --- a/crypto/dh/dh_err.c +++ b/crypto/dh/dh_err.c @@ -82,6 +82,7 @@ static ERR_STRING_DATA DH_str_functs[]= static ERR_STRING_DATA DH_str_reasons[]= { {ERR_REASON(DH_R_BAD_GENERATOR) ,"bad generator"}, +{ERR_REASON(DH_R_MODULUS_TOO_LARGE) ,"modulus too large"}, {ERR_REASON(DH_R_NO_PRIVATE_VALUE) ,"no private value"}, {0,NULL} }; diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c index 3a39f7c8ca..c6e618bca2 100644 --- a/crypto/dh/dh_key.c +++ b/crypto/dh/dh_key.c @@ -180,6 +180,12 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) BIGNUM *tmp; int ret= -1; + if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) + { + DHerr(DH_F_DH_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE); + goto err; + } + ctx = BN_CTX_new(); if (ctx == NULL) goto err; BN_CTX_start(ctx); diff --git a/crypto/dsa/dsa.h b/crypto/dsa/dsa.h index 851e3f0445..6948f86834 100644 --- a/crypto/dsa/dsa.h +++ b/crypto/dsa/dsa.h @@ -79,6 +79,10 @@ # include #endif +#ifndef OPENSSL_DSA_MAX_MODULUS_BITS +# define OPENSSL_DSA_MAX_MODULUS_BITS 10000 +#endif + #define DSA_FLAG_CACHE_MONT_P 0x01 #define DSA_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DSA * implementation now uses constant time @@ -259,8 +263,10 @@ void ERR_load_DSA_strings(void); #define DSA_F_SIG_CB 114 /* Reason codes. */ +#define DSA_R_BAD_Q_VALUE 102 #define DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 100 #define DSA_R_MISSING_PARAMETERS 101 +#define DSA_R_MODULUS_TOO_LARGE 103 #ifdef __cplusplus } diff --git a/crypto/dsa/dsa_err.c b/crypto/dsa/dsa_err.c index fd42053572..d7fac69154 100644 --- a/crypto/dsa/dsa_err.c +++ b/crypto/dsa/dsa_err.c @@ -89,8 +89,10 @@ static ERR_STRING_DATA DSA_str_functs[]= static ERR_STRING_DATA DSA_str_reasons[]= { +{ERR_REASON(DSA_R_BAD_Q_VALUE) ,"bad q value"}, {ERR_REASON(DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE),"data too large for key size"}, {ERR_REASON(DSA_R_MISSING_PARAMETERS) ,"missing parameters"}, +{ERR_REASON(DSA_R_MODULUS_TOO_LARGE) ,"modulus too large"}, {0,NULL} }; diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c index 12509a7083..5de5fc7e91 100644 --- a/crypto/dsa/dsa_ossl.c +++ b/crypto/dsa/dsa_ossl.c @@ -274,6 +274,18 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, return -1; } + if (BN_num_bits(dsa->q) != 160) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE); + return -1; + } + + if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE); + return -1; + } + BN_init(&u1); BN_init(&u2); BN_init(&t1); diff --git a/crypto/rsa/rsa.h b/crypto/rsa/rsa.h index 0b639cd37f..9eda269586 100644 --- a/crypto/rsa/rsa.h +++ b/crypto/rsa/rsa.h @@ -154,6 +154,17 @@ struct rsa_st BN_BLINDING *blinding; }; +#ifndef OPENSSL_RSA_MAX_MODULUS_BITS +# define OPENSSL_RSA_MAX_MODULUS_BITS 16384 +#endif + +#ifndef OPENSSL_RSA_SMALL_MODULUS_BITS +# define OPENSSL_RSA_SMALL_MODULUS_BITS 3072 +#endif +#ifndef OPENSSL_RSA_MAX_PUBEXP_BITS +# define OPENSSL_RSA_MAX_PUBEXP_BITS 64 /* exponent limit enforced for "large" modulus only */ +#endif + #define RSA_3 0x3L #define RSA_F4 0x10001L @@ -386,6 +397,7 @@ void ERR_load_RSA_strings(void); #define RSA_R_IQMP_NOT_INVERSE_OF_Q 126 #define RSA_R_KEY_SIZE_TOO_SMALL 120 #define RSA_R_LAST_OCTET_INVALID 134 +#define RSA_R_MODULUS_TOO_LARGE 105 #define RSA_R_NULL_BEFORE_BLOCK_MISSING 113 #define RSA_R_N_DOES_NOT_EQUAL_P_Q 127 #define RSA_R_OAEP_DECODING_ERROR 121 diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c index d1986c1908..6791c66bbc 100644 --- a/crypto/rsa/rsa_eay.c +++ b/crypto/rsa/rsa_eay.c @@ -157,6 +157,28 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *buf=NULL; BN_CTX *ctx=NULL; + if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE); + return -1; + } + + if (BN_ucmp(rsa->n, rsa->e) <= 0) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); + return -1; + } + + /* for large moduli, enforce exponent limit */ + if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) + { + if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); + return -1; + } + } + BN_init(&f); BN_init(&ret); if ((ctx=BN_CTX_new()) == NULL) goto err; @@ -600,6 +622,28 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *buf=NULL; BN_CTX *ctx=NULL; + if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE); + return -1; + } + + if (BN_ucmp(rsa->n, rsa->e) <= 0) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); + return -1; + } + + /* for large moduli, enforce exponent limit */ + if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) + { + if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) + { + RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); + return -1; + } + } + BN_init(&f); BN_init(&ret); ctx=BN_CTX_new(); diff --git a/crypto/rsa/rsa_err.c b/crypto/rsa/rsa_err.c index 2ec4b30ff7..ddcb28e663 100644 --- a/crypto/rsa/rsa_err.c +++ b/crypto/rsa/rsa_err.c @@ -129,6 +129,7 @@ static ERR_STRING_DATA RSA_str_reasons[]= {ERR_REASON(RSA_R_IQMP_NOT_INVERSE_OF_Q) ,"iqmp not inverse of q"}, {ERR_REASON(RSA_R_KEY_SIZE_TOO_SMALL) ,"key size too small"}, {ERR_REASON(RSA_R_LAST_OCTET_INVALID) ,"last octet invalid"}, +{ERR_REASON(RSA_R_MODULUS_TOO_LARGE) ,"modulus too large"}, {ERR_REASON(RSA_R_NULL_BEFORE_BLOCK_MISSING),"null before block missing"}, {ERR_REASON(RSA_R_N_DOES_NOT_EQUAL_P_Q) ,"n does not equal p q"}, {ERR_REASON(RSA_R_OAEP_DECODING_ERROR) ,"oaep decoding error"}, diff --git a/ssl/s2_clnt.c b/ssl/s2_clnt.c index eba04c715b..215e4f8f53 100644 --- a/ssl/s2_clnt.c +++ b/ssl/s2_clnt.c @@ -538,7 +538,8 @@ static int get_server_hello(SSL *s) CRYPTO_add(&s->session->peer->references, 1, CRYPTO_LOCK_X509); } - if (s->session->peer != s->session->sess_cert->peer_key->x509) + if (s->session->sess_cert == NULL + || s->session->peer != s->session->sess_cert->peer_key->x509) /* can't happen */ { ssl2_return_error(s, SSL2_PE_UNDEFINED_ERROR); diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c index 36fc39d7f8..98d0a075e5 100644 --- a/ssl/s3_srvr.c +++ b/ssl/s3_srvr.c @@ -1727,7 +1727,7 @@ static int ssl3_get_client_key_exchange(SSL *s) if (kssl_ctx->client_princ) { - int len = strlen(kssl_ctx->client_princ); + size_t len = strlen(kssl_ctx->client_princ); if ( len < SSL_MAX_KRB5_PRINCIPAL_LENGTH ) { s->session->krb5_client_princ_len = len; diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index 2bd9a5af86..4e8f302a5e 100644 --- a/ssl/ssl_lib.c +++ b/ssl/ssl_lib.c @@ -1187,7 +1187,7 @@ char *SSL_get_shared_ciphers(const SSL *s,char *buf,int len) c=sk_SSL_CIPHER_value(sk,i); for (cp=c->name; *cp; ) { - if (len-- == 0) + if (len-- <= 0) { *p='\0'; return(buf); -- 2.25.1