2013-12-19 15:34:12

by Horia Geantă

Subject: [PATCH] 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 <[email protected]>
---
drivers/crypto/caam/caamalg.c | 36 +++++++++++++-----------------------
1 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index 4cf5dec..b71f2fd 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;
--
1.7.7.6

2013-12-20 14:08:32

by Herbert Xu

Subject: Re: [PATCH] crypto: caam - simplify and harden key parsing

On Thu, Dec 19, 2013 at 05:27:35PM +0200, Horia Geanta wrote:
> 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 <[email protected]>

Patch applied. Thanks!
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt