Patch "crypto: dh - Don't permit 'key' or 'g' size longer than 'p'" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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;a=summary

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