crypto: caam - simplify and harden key parsing

Use the common helper function crypto_authenc_extractkeys() for key
parsing.
Also fix the key buffer overflow condition: use split key pad length
instead of authentication key length.

Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 13 insertions, 23 deletions

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index 4cf5dec826e1..b71f2fd749df 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -467,24 +467,10 @@ static int aead_setkey(struct crypto_aead *aead,
         static const u8 mdpadlen[] = { 16, 20, 32, 32, 64, 64 };
         struct caam_ctx *ctx = crypto_aead_ctx(aead);
         struct device *jrdev = ctx->jrdev;
-        struct rtattr *rta = (void *)key;
-        struct crypto_authenc_key_param *param;
-        unsigned int authkeylen;
-        unsigned int enckeylen;
+        struct crypto_authenc_keys keys;
         int ret = 0;
 
-        param = RTA_DATA(rta);
-        enckeylen = be32_to_cpu(param->enckeylen);
-
-        key += RTA_ALIGN(rta->rta_len);
-        keylen -= RTA_ALIGN(rta->rta_len);
-
-        if (keylen < enckeylen)
-                goto badkey;
-
-        authkeylen = keylen - enckeylen;
-
-        if (keylen > CAAM_MAX_KEY_SIZE)
+        if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
                 goto badkey;
 
         /* Pick class 2 key length from algorithm submask */
@@ -492,25 +478,29 @@ static int aead_setkey(struct crypto_aead *aead,
                                       OP_ALG_ALGSEL_SHIFT] * 2;
         ctx->split_key_pad_len = ALIGN(ctx->split_key_len, 16);
 
+        if (ctx->split_key_pad_len + keys.enckeylen > CAAM_MAX_KEY_SIZE)
+                goto badkey;
+
 #ifdef DEBUG
         printk(KERN_ERR "keylen %d enckeylen %d authkeylen %d\n",
-               keylen, enckeylen, authkeylen);
+               keys.authkeylen + keys.enckeylen, keys.enckeylen,
+               keys.authkeylen);
         printk(KERN_ERR "split_key_len %d split_key_pad_len %d\n",
                ctx->split_key_len, ctx->split_key_pad_len);
         print_hex_dump(KERN_ERR, "key in @"__stringify(__LINE__)": ",
                        DUMP_PREFIX_ADDRESS, 16, 4, key, keylen, 1);
 #endif
 
-        ret = gen_split_aead_key(ctx, key, authkeylen);
+        ret = gen_split_aead_key(ctx, keys.authkey, keys.authkeylen);
         if (ret) {
                 goto badkey;
         }
 
         /* postpend encryption key to auth split key */
-        memcpy(ctx->key + ctx->split_key_pad_len, key + authkeylen, enckeylen);
+        memcpy(ctx->key + ctx->split_key_pad_len, keys.enckey, keys.enckeylen);
 
         ctx->key_dma = dma_map_single(jrdev, ctx->key, ctx->split_key_pad_len +
-                                       enckeylen, DMA_TO_DEVICE);
+                                      keys.enckeylen, DMA_TO_DEVICE);
         if (dma_mapping_error(jrdev, ctx->key_dma)) {
                 dev_err(jrdev, "unable to map key i/o memory\n");
                 return -ENOMEM;
@@ -518,15 +508,15 @@ static int aead_setkey(struct crypto_aead *aead,
 #ifdef DEBUG
         print_hex_dump(KERN_ERR, "ctx.key@"__stringify(__LINE__)": ",
                        DUMP_PREFIX_ADDRESS, 16, 4, ctx->key,
-                       ctx->split_key_pad_len + enckeylen, 1);
+                       ctx->split_key_pad_len + keys.enckeylen, 1);
 #endif
 
-        ctx->enckeylen = enckeylen;
+        ctx->enckeylen = keys.enckeylen;
 
         ret = aead_set_sh_desc(aead);
         if (ret) {
                 dma_unmap_single(jrdev, ctx->key_dma, ctx->split_key_pad_len +
-                                 enckeylen, DMA_TO_DEVICE);
+                                 keys.enckeylen, DMA_TO_DEVICE);
         }
 
         return ret;