crypto: user - fix info leaks in report API

commit 9a5467bf7b6e9e02ec9c3da4e23747c05faeaac6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 8d3a056ebeeaf250d5ec61f4fe0cba990001528c..45fe4109698e4898cb31602102c9c970b3253cce 100644 (file)
--- 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 e4cb35159be43fe365ec569908f84732c5c67042..c706d7415de052e6cb8c8c122c49ee6294908fed 100644 (file)
--- 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 33bc9b62e9ae5dde4a977c00293efc2ca2998a71..0ec05feea43814d692ca9589244496891f6a7819 100644 (file)
--- 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 4dd80c725498a3bb48cd9f4c961baced47f9cc6c..0a1ebea3d6fc3b14305bfcf83c85122545b41f08 100644 (file)
--- 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 f1ea0a0641350cbd0f7628bc3e7edde4fc38972d..910497bd72be0600fc6ecac620f1d97d1f7ce63f 100644 (file)
--- 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));
        NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
                sizeof(struct crypto_report_comp), &rcomp);
 
@@ -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));
                NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
                        sizeof(struct crypto_report_larval), &rl);
 

diff --git a/crypto/pcompress.c b/crypto/pcompress.c
index 2e458e5482d0c5708cbab83dddaad11215c28a0e..6f2a361bb03e5a46d8527916b0017038cb6faec9 100644 (file)
--- 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));
        NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
                sizeof(struct crypto_report_comp), &rpcomp);
 

diff --git a/crypto/rng.c b/crypto/rng.c
index 64f864fa8043740f50bc186e58a2ee37d8a1499a..1966c1d0d7f00ff9cd6635d11d4780bf09cbdaf8 100644 (file)
--- 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 21fc12e2378f17340d40f264af6deeab51f214d5..3b2a71f6660e9ff9fd4f7132ea73db324bce7125 100644 (file)
--- 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;