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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index a0f768c1d9aa75fdb94a70dba711e175d8f66c9f..9f73037708b2a5e028a2fdb65ba5155b82b17ddd 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 04add3dca6fe44dfc242e89a36741c56786327fa..479b7d134f246f3ef009753fe8950e8ce25114fc 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 ac93c99cfae85abbc7fa433d94ef3fe80437cbb0..7fe175233c619a17aa035483e8a5456110c07ecc 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 1e61d1a888b2b76f1b1e2fc8ac67e7741b221f45..04f0f388adf1bd1f274f61d89c48e5dfc30664cf 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 0605a2bbba75e17e67e59f602f1d12c453404031..5b63b8dd1f9f1f44d8961a6b5f21b2f5e9fbe7c0 100644 (file)
--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -71,7 +71,7 @@ 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;
@@ -90,8 +90,7 @@ 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);
 
@@ -104,12 +103,14 @@ 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);
 
@@ -118,8 +119,7 @@ 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 9100912716ae948fa57da13b9030a248f0460942..f507294f281198d35b41b1b3692bdad52c877745 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;