On (10/12/15 21:32), Herbert Xu wrote:
>
> .. pkcs7_verify definitely
> shouldn't place the structure after the digest without aligning the
> pointer. So something like your patch is needed (but please use
> alignof instead of sizeof). Also don't put in digest_size but
> instead align the pointer like
>
> desc = PTR_ALIGN(digest + digest_size, ...)
I tried the patch below for 24+ hours, and it ran without mishaps.
But given that the panics I saw earlier (page faults typically
triggered by openswan's pluto) occurred unpredictably, it would be
useful to have an expert-review of this code.
Thanks,
--Sowmini
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c
b/crypto/asymmetric_keys/pkcs7_verify.c
index d20c0b4..958ac01 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -46,14 +46,15 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
- sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
-
+ sinfo->sig.digest_size = crypto_shash_digestsize(tfm);
+ digest_size = crypto_shash_digestsize(tfm) +
+ ALIGN(crypto_shash_digestsize(tfm), __alignof__(*desc));
ret = -ENOMEM;
digest = kzalloc(digest_size + 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;
--
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