2020-05-02 18:28:48

by Eric Biggers

Subject: [PATCH 1/7] mptcp: use SHA256_BLOCK_SIZE, not SHA_MESSAGE_BYTES

From: Eric Biggers <[email protected]>

In preparation for naming the SHA-1 stuff in <linux/cryptohash.h>
properly and moving it to a more appropriate header, fix the HMAC-SHA256
code in mptcp_crypto_hmac_sha() to use SHA256_BLOCK_SIZE instead of
"SHA_MESSAGE_BYTES" which is actually the SHA-1 block size.
(Fortunately these are both 64 bytes, so this wasn't a "real" bug...)

Cc: Paolo Abeni <[email protected]>
Cc: [email protected]
Signed-off-by: Eric Biggers <[email protected]>
---
net/mptcp/crypto.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/crypto.c b/net/mptcp/crypto.c
index c151628bd4161a..81b06d875f9249 100644
--- a/net/mptcp/crypto.c
+++ b/net/mptcp/crypto.c
@@ -61,7 +61,7 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
put_unaligned_be64(key2, key2be);

/* Generate key xored with ipad */
- memset(input, 0x36, SHA_MESSAGE_BYTES);
+ memset(input, 0x36, SHA256_BLOCK_SIZE);
for (i = 0; i < 8; i++)
input[i] ^= key1be[i];
for (i = 0; i < 8; i++)
@@ -78,7 +78,7 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
sha256_final(&state, &input[SHA256_BLOCK_SIZE]);

/* Prepare second part of hmac */
- memset(input, 0x5C, SHA_MESSAGE_BYTES);
+ memset(input, 0x5C, SHA256_BLOCK_SIZE);
for (i = 0; i < 8; i++)
input[i] ^= key1be[i];
for (i = 0; i < 8; i++)
--
2.26.2

2020-05-02 18:57:05

by Matthieu Baerts

Subject: Re: [MPTCP] [PATCH 1/7] mptcp: use SHA256_BLOCK_SIZE, not SHA_MESSAGE_BYTES

Hi Eric,

On 02/05/2020 20:24, Eric Biggers wrote:
> From: Eric Biggers <[email protected]>
>
> In preparation for naming the SHA-1 stuff in <linux/cryptohash.h>
> properly and moving it to a more appropriate header, fix the HMAC-SHA256
> code in mptcp_crypto_hmac_sha() to use SHA256_BLOCK_SIZE instead of
> "SHA_MESSAGE_BYTES" which is actually the SHA-1 block size.
> (Fortunately these are both 64 bytes, so this wasn't a "real" bug...)

Good catch! I guess it was left when switching from SHA-1 to SHA-256 in
65492c5a6ab5 (mptcp: move from sha1 (v0) to sha256 (v1)).

For MPTCP related code, it looks good to me, thank you for this!

Reviewed-by: Matthieu Baerts <[email protected]>

--
Matthieu Baerts | R&D Engineer
[email protected]
Tessares SA | Hybrid Access Solutions
http://www.tessares.net
1 Avenue Jean Monnet, 1348 Louvain-la-Neuve, Belgium