This is a note to let you know that I've just added the patch titled

crypto: dh - Don't permit 'key' or 'g' size longer than 'p'

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: crypto-dh-don-t-permit-key-or-g-size-longer-than-p.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From ccd9888f14a8019c0bbdeeae758aba1f58693712 Mon Sep 17 00:00:00 2001

From: Eric Biggers ebiggers@google.com Date: Sun, 5 Nov 2017 18:30:46 -0800 Subject: crypto: dh - Don't permit 'key' or 'g' size longer than 'p'

From: Eric Biggers ebiggers@google.com

commit ccd9888f14a8019c0bbdeeae758aba1f58693712 upstream.

The "qat-dh" DH implementation assumes that 'key' and 'g' can be copied into a buffer with size 'p_size'. However it was never checked that that was actually the case, which most likely allowed users to cause a buffer underflow via KEYCTL_DH_COMPUTE.

Fix this by updating crypto_dh_decode_key() to verify this precondition for all DH implementations.

Fixes: c9839143ebbf ("crypto: qat - Add DH support") Signed-off-by: Eric Biggers ebiggers@google.com Reviewed-by: Tudor Ambarus tudor.ambarus@microchip.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- crypto/dh_helper.c | 8 ++++++++ 1 file changed, 8 insertions(+)

--- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -83,6 +83,14 @@ int crypto_dh_decode_key(const char *buf if (secret.len != crypto_dh_key_len(params)) return -EINVAL;

+ /* + * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since + * some drivers assume otherwise. + */ + if (params->key_size > params->p_size || + params->g_size > params->p_size) + return -EINVAL; + /* Don't allocate memory. Set pointers to data within * the given buffer */

Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.9/crypto-dh-don-t-permit-key-or-g-size-longer-than-p.patch queue-4.9/arm-crypto-reduce-priority-of-bit-sliced-aes-cipher.patch queue-4.9/crypto-dh-don-t-permit-p-to-be-0.patch