From 9a5467bf7b6e9e02ec9c3da4e23747c05faeaac6 Mon Sep 17 00:00:00 2001

From: Mathias Krause <minipli@googlemail.com>

Date: Tue, 5 Feb 2013 18:19:13 +0100

Subject: [PATCH] crypto: user - fix info leaks in report API

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 <minipli@googlemail.com>

Cc: Steffen Klassert <steffen.klassert@secunet.com>

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

---

 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 ?: "<default>");

+	strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));

+	strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",

+		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 ?: "<built-in>");

+	strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));

+	strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",

+		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 4d04e12..547491e 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 ?: "<built-in>");

+	strncpy(raead.type, "aead", sizeof(raead.type));

+	strncpy(raead.geniv, aead->geniv ?: "<built-in>", 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 e9e7244..a79e7e9 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 ?: "<default>");

+	strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));

+	strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",

+		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;

-- 

1.8.1.2