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KEYS: DH: ensure the KDF counter is properly aligned

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Accessing a 'u8[4]' through a '__be32 *' violates alignment rules.  Just
make the counter a __be32 instead.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Eric Biggers 2017-06-08 14:49:49 +01:00 committed by James Morris
parent 281590b422
commit 0ddd9f1a6b
1 changed files with 3 additions and 13 deletions
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16
security/keys/dh.c
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@ -130,14 +130,6 @@ static void kdf_dealloc(struct kdf_sdesc *sdesc)
kzfree(sdesc);
}
/* convert 32 bit integer into its string representation */
static inline void crypto_kw_cpu_to_be32(u32 val, u8 *buf)
{
__be32 *a = (__be32 *)buf;
*a = cpu_to_be32(val);
}
/*
* Implementation of the KDF in counter mode according to SP800-108 section 5.1
* as well as SP800-56A section 5.8.1 (Single-step KDF).
@ -154,16 +146,14 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
unsigned int h = crypto_shash_digestsize(desc->tfm);
int err = 0;
u8 *dst_orig = dst;
u32 i = 1;
u8 iteration[sizeof(u32)];
__be32 counter = cpu_to_be32(1);
while (dlen) {
err = crypto_shash_init(desc);
if (err)
goto err;
crypto_kw_cpu_to_be32(i, iteration);
err = crypto_shash_update(desc, iteration, sizeof(u32));
err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
if (err)
goto err;
@ -189,7 +179,7 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
dlen -= h;
dst += h;
i++;
counter = cpu_to_be32(be32_to_cpu(counter) + 1);
}
}