Patch "crypto: dh - Don't permit 'key' or 'g' size longer than 'p'" has been added to the 4.13-stable tree

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 4.13-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-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Eric Biggers <[email protected]>
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 <[email protected]>

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.

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

@@ -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 [email protected] are

queue-4.13/crypto-dh-don-t-permit-key-or-g-size-longer-than-p.patch queue-4.13/crypto-dh-don-t-permit-p-to-be-0.patch queue-4.13/crypto-dh-fix-double-free-of-ctx-p.patch