From: Mathias Krause Subject: [PATCHv2 1/3] crypto: user - fix info leaks in report API Date: Tue, 5 Feb 2013 18:19:13 +0100 Message-ID: <1360084755-11044-2-git-send-email-minipli@googlemail.com> References: <1360084755-11044-1-git-send-email-minipli@googlemail.com> Cc: Steffen Klassert , linux-crypto@vger.kernel.org, Mathias Krause To: Herbert Xu , "David S. Miller" Return-path: Received: from mail-bk0-f45.google.com ([209.85.214.45]:36311 "EHLO mail-bk0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755590Ab3BERTe (ORCPT ); Tue, 5 Feb 2013 12:19:34 -0500 Received: by mail-bk0-f45.google.com with SMTP id i18so203776bkv.4 for ; Tue, 05 Feb 2013 09:19:33 -0800 (PST) In-Reply-To: <1360084755-11044-1-git-send-email-minipli@googlemail.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Three errors resulting in kernel memory disclosure: 1/ The structures used for the netlink based crypto algorithm report API are located on the stack. As snprintf() does not fill the remainder of the buffer with null bytes, those stack bytes will be disclosed to users of the API. Switch to strncpy() to fix this. 2/ crypto_report_one() does not initialize all field of struct crypto_user_alg. Fix this to fix the heap info leak. 3/ For the module name we should copy only as many bytes as module_name() returns -- not as much as the destination buffer could hold. But the current code does not and therefore copies random data from behind the end of the module name, as the module name is always shorter than CRYPTO_MAX_ALG_NAME. Also switch to use strncpy() to copy the algorithm's name and driver_name. They are strings, after all. Signed-off-by: Mathias Krause Cc: Steffen Klassert --- crypto/ablkcipher.c | 12 ++++++------ crypto/aead.c | 9 ++++----- crypto/ahash.c | 2 +- crypto/blkcipher.c | 6 +++--- crypto/crypto_user.c | 22 +++++++++++----------- crypto/pcompress.c | 3 +-- crypto/rng.c | 2 +- crypto/shash.c | 3 ++- 8 files changed, 29 insertions(+), 30 deletions(-) diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c index 533de95..7d4a8d2 100644 --- a/crypto/ablkcipher.c +++ b/crypto/ablkcipher.c @@ -388,9 +388,9 @@ static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_blkcipher rblkcipher; - snprintf(rblkcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "ablkcipher"); - snprintf(rblkcipher.geniv, CRYPTO_MAX_ALG_NAME, "%s", - alg->cra_ablkcipher.geniv ?: ""); + strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type)); + strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "", + sizeof(rblkcipher.geniv)); rblkcipher.blocksize = alg->cra_blocksize; rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize; @@ -469,9 +469,9 @@ static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_blkcipher rblkcipher; - snprintf(rblkcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "givcipher"); - snprintf(rblkcipher.geniv, CRYPTO_MAX_ALG_NAME, "%s", - alg->cra_ablkcipher.geniv ?: ""); + strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type)); + strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "", + sizeof(rblkcipher.geniv)); rblkcipher.blocksize = alg->cra_blocksize; rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize; diff --git a/crypto/aead.c b/crypto/aead.c index 0b8121e..27bc487 100644 --- a/crypto/aead.c +++ b/crypto/aead.c @@ -117,9 +117,8 @@ static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg) struct crypto_report_aead raead; struct aead_alg *aead = &alg->cra_aead; - snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "aead"); - snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s", - aead->geniv ?: ""); + strncpy(raead.type, "aead", sizeof(raead.type)); + strncpy(raead.geniv, aead->geniv ?: "", sizeof(raead.geniv)); raead.blocksize = alg->cra_blocksize; raead.maxauthsize = aead->maxauthsize; @@ -203,8 +202,8 @@ static int crypto_nivaead_report(struct sk_buff *skb, struct crypto_alg *alg) struct crypto_report_aead raead; struct aead_alg *aead = &alg->cra_aead; - snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "nivaead"); - snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s", aead->geniv); + strncpy(raead.type, "nivaead", sizeof(raead.type)); + strncpy(raead.geniv, aead->geniv, sizeof(raead.geniv)); raead.blocksize = alg->cra_blocksize; raead.maxauthsize = aead->maxauthsize; diff --git a/crypto/ahash.c b/crypto/ahash.c index 3887856..793a27f 100644 --- a/crypto/ahash.c +++ b/crypto/ahash.c @@ -404,7 +404,7 @@ static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_hash rhash; - snprintf(rhash.type, CRYPTO_MAX_ALG_NAME, "%s", "ahash"); + strncpy(rhash.type, "ahash", sizeof(rhash.type)); rhash.blocksize = alg->cra_blocksize; rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize; diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c index a8d85a1..c44e014 100644 --- a/crypto/blkcipher.c +++ b/crypto/blkcipher.c @@ -499,9 +499,9 @@ static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_blkcipher rblkcipher; - snprintf(rblkcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "blkcipher"); - snprintf(rblkcipher.geniv, CRYPTO_MAX_ALG_NAME, "%s", - alg->cra_blkcipher.geniv ?: ""); + strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type)); + strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "", + sizeof(rblkcipher.geniv)); rblkcipher.blocksize = alg->cra_blocksize; rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize; diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c index 35d700a..f6d9baf 100644 --- a/crypto/crypto_user.c +++ b/crypto/crypto_user.c @@ -75,7 +75,7 @@ static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_cipher rcipher; - snprintf(rcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "cipher"); + strncpy(rcipher.type, "cipher", sizeof(rcipher.type)); rcipher.blocksize = alg->cra_blocksize; rcipher.min_keysize = alg->cra_cipher.cia_min_keysize; @@ -94,8 +94,7 @@ static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_comp rcomp; - snprintf(rcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "compression"); - + strncpy(rcomp.type, "compression", sizeof(rcomp.type)); if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(struct crypto_report_comp), &rcomp)) goto nla_put_failure; @@ -108,12 +107,14 @@ nla_put_failure: static int crypto_report_one(struct crypto_alg *alg, struct crypto_user_alg *ualg, struct sk_buff *skb) { - memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name)); - memcpy(&ualg->cru_driver_name, &alg->cra_driver_name, - sizeof(ualg->cru_driver_name)); - memcpy(&ualg->cru_module_name, module_name(alg->cra_module), - CRYPTO_MAX_ALG_NAME); - + strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name)); + strncpy(ualg->cru_driver_name, alg->cra_driver_name, + sizeof(ualg->cru_driver_name)); + strncpy(ualg->cru_module_name, module_name(alg->cra_module), + sizeof(ualg->cru_module_name)); + + ualg->cru_type = 0; + ualg->cru_mask = 0; ualg->cru_flags = alg->cra_flags; ualg->cru_refcnt = atomic_read(&alg->cra_refcnt); @@ -122,8 +123,7 @@ static int crypto_report_one(struct crypto_alg *alg, if (alg->cra_flags & CRYPTO_ALG_LARVAL) { struct crypto_report_larval rl; - snprintf(rl.type, CRYPTO_MAX_ALG_NAME, "%s", "larval"); - + strncpy(rl.type, "larval", sizeof(rl.type)); if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(struct crypto_report_larval), &rl)) goto nla_put_failure; diff --git a/crypto/pcompress.c b/crypto/pcompress.c index 04e083f..7140fe7 100644 --- a/crypto/pcompress.c +++ b/crypto/pcompress.c @@ -53,8 +53,7 @@ static int crypto_pcomp_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_comp rpcomp; - snprintf(rpcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "pcomp"); - + strncpy(rpcomp.type, "pcomp", sizeof(rpcomp.type)); if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(struct crypto_report_comp), &rpcomp)) goto nla_put_failure; diff --git a/crypto/rng.c b/crypto/rng.c index f3b7894..e0a25c2 100644 --- a/crypto/rng.c +++ b/crypto/rng.c @@ -65,7 +65,7 @@ static int crypto_rng_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_rng rrng; - snprintf(rrng.type, CRYPTO_MAX_ALG_NAME, "%s", "rng"); + strncpy(rrng.type, "rng", sizeof(rrng.type)); rrng.seedsize = alg->cra_rng.seedsize; diff --git a/crypto/shash.c b/crypto/shash.c index f426330f..929058a 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -530,7 +530,8 @@ static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg) struct crypto_report_hash rhash; struct shash_alg *salg = __crypto_shash_alg(alg); - snprintf(rhash.type, CRYPTO_MAX_ALG_NAME, "%s", "shash"); + strncpy(rhash.type, "shash", sizeof(rhash.type)); + rhash.blocksize = alg->cra_blocksize; rhash.digestsize = salg->digestsize; -- 1.7.10.4