2015-10-13 14:54:01

by Sowmini Varadhan

Subject: [PATCH] crypto/pkcs7_verify: Fix unaligned access in pkcs7_verify()

On sparc, we see unaligned access messages on each modprobe[-r]:

Kernel unaligned access at TPC[6ad9b4] pkcs7_verify [..]
Kernel unaligned access at TPC[6a5484] crypto_shash_finup [..]
Kernel unaligned access at TPC[6a5390] crypto_shash_update [..]
Kernel unaligned access at TPC[10150308] sha1_sparc64_update [..]
Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update [..]

These ware triggered by mod_verify_sig() invocations of pkcs_verify(), and
are are being caused by an unaligned desc at (sha1, digest_size is 0x14)
desc = digest + digest_size;

To fix this, pkcs7_verify needs to make sure that desc is pointing
at an aligned value past the digest_size, and kzalloc appropriately,
taking alignment values into consideration.

Signed-off-by: Sowmini Varadhan <[email protected]>
---
crypto/asymmetric_keys/pkcs7_verify.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index d20c0b4..325575c 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -49,11 +49,12 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);

ret = -ENOMEM;
- digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
+ digest = kzalloc(ALIGN(digest_size, __alignof__(*desc)) + desc_size,
+ GFP_KERNEL);
if (!digest)
goto error_no_desc;

- desc = digest + digest_size;
+ desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
desc->tfm = tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

--
1.7.1

2015-10-14 14:29:15

by Herbert Xu

Subject: Re: [PATCH] crypto/pkcs7_verify: Fix unaligned access in pkcs7_verify()

On Tue, Oct 13, 2015 at 10:54:01AM -0400, Sowmini Varadhan wrote:
>
> On sparc, we see unaligned access messages on each modprobe[-r]:
>
> Kernel unaligned access at TPC[6ad9b4] pkcs7_verify [..]
> Kernel unaligned access at TPC[6a5484] crypto_shash_finup [..]
> Kernel unaligned access at TPC[6a5390] crypto_shash_update [..]
> Kernel unaligned access at TPC[10150308] sha1_sparc64_update [..]
> Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update [..]
>
> These ware triggered by mod_verify_sig() invocations of pkcs_verify(), and
> are are being caused by an unaligned desc at (sha1, digest_size is 0x14)
> desc = digest + digest_size;
>
> To fix this, pkcs7_verify needs to make sure that desc is pointing
> at an aligned value past the digest_size, and kzalloc appropriately,
> taking alignment values into consideration.
>
> Signed-off-by: Sowmini Varadhan <[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

2015-10-15 15:16:10

by David Howells

Subject: Re: [PATCH] crypto/pkcs7_verify: Fix unaligned access in pkcs7_verify()

Sowmini Varadhan <[email protected]> wrote:

> On sparc, we see unaligned access messages on each modprobe[-r]:
>
> Kernel unaligned access at TPC[6ad9b4] pkcs7_verify [..]
> Kernel unaligned access at TPC[6a5484] crypto_shash_finup [..]
> Kernel unaligned access at TPC[6a5390] crypto_shash_update [..]
> Kernel unaligned access at TPC[10150308] sha1_sparc64_update [..]
> Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update [..]
>
> These ware triggered by mod_verify_sig() invocations of pkcs_verify(), and
> are are being caused by an unaligned desc at (sha1, digest_size is 0x14)
> desc = digest + digest_size;
>
> To fix this, pkcs7_verify needs to make sure that desc is pointing
> at an aligned value past the digest_size, and kzalloc appropriately,
> taking alignment values into consideration.
>
> Signed-off-by: Sowmini Varadhan <[email protected]>

Acked-by: David Howells <[email protected]>