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crypto/pkcs7_verify: Fix unaligned access in pkcs7_verify()

PATCH In review Sowmini Varadhan 3 participants 3 messages Oct 13, 2015 – Oct 15, 2015

Subsystems (2)
Crypto API Asymmetric keys
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Sowmini Varadhan

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#0 lore raw

PATCH 1/1 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(-)
crypto/asymmetric_keys/pkcs7_verify.c +3 -2
index d20c0b4..325575c 100644
@@ -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;
Signature · 1 line
1.7.1
maintainer
#1 lore raw
Quoted 11 lines · Sowmini Varadhan

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)

Quoted 7 lines
        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!

Signature · 3 lines
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
maintainer Acked-by on v1 1/1
#2 lore raw
In reply to Sowmini Varadhan
Quoted 10 lines · Sowmini Varadhan

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)

Quoted 7 lines
        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]>