[Devel] [PATCH RHEL7 COMMIT] ms/crypto: gcm - Fix rfc4543 decryption crash

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.19.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.19.3
------>
commit ac8ac641c0038eb46460ec71bb3c1db748bd1e2b
Author: Herbert Xu <herbert at gondor.apana.org.au>
Date:   Mon Oct 24 16:34:08 2016 +0400

    ms/crypto: gcm - Fix rfc4543 decryption crash
    
    This bug has already bee fixed upstream since 4.2.  However, it
    was fixed during the AEAD conversion so no fix was backported to
    the older kernels.
    
    When we do an RFC 4543 decryption, we will end up writing the
    ICV beyond the end of the dst buffer.  This should lead to a
    crash but for some reason it was never noticed.
    
    This patch fixes it by only writing back the ICV for encryption.
    
    Fixes: d733ac90f9fe ("crypto: gcm - fix rfc4543 to handle async...")
    Reported-by: Patrick Meyer <patrick.meyer at vasgard.com>
    Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
    Signed-off-by: Jiri Slaby <jslaby at suse.cz>
    
    Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 crypto/gcm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/crypto/gcm.c b/crypto/gcm.c
index 9cea4d0..f0bd00b 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -1173,6 +1173,9 @@ static struct aead_request *crypto_rfc4543_crypt(struct aead_request *req,
 	aead_request_set_tfm(subreq, ctx->child);
 	aead_request_set_callback(subreq, req->base.flags, crypto_rfc4543_done,
 				  req);
+	if (!enc)
+		aead_request_set_callback(subreq, req->base.flags,
+					  req->base.complete, req->base.data);
 	aead_request_set_crypt(subreq, cipher, cipher, enc ? 0 : authsize, iv);
 	aead_request_set_assoc(subreq, assoc, assoclen);