From: Dave Watson <davejwatson@fb.com>
Date: Fri, 19 Jan 2018 12:30:13 -0800
Subject: tls: Correct length of scatterlist in tls_sw_sendpage
Patch-mainline: v4.15
Git-commit: 7a8c4dd9be91a7e8f8f0e0419a560663adc694a3
References: bsc#1103990 FATE#326006

The scatterlist is reused by both sendmsg and sendfile.
If a sendmsg of smaller number of pages is followed by a sendfile
of larger number of pages, the scatterlist may be too short, resulting
in a crash in gcm_encrypt.

Add sg_unmark_end to make the list the correct length.

tls_sw_sendmsg already calls sg_unmark_end correctly when it allocates
memory in alloc_sg, or in zerocopy_from_iter.

Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/tls/tls_sw.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -577,6 +577,8 @@ alloc_payload:
 		get_page(page);
 		sg = ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem;
 		sg_set_page(sg, page, copy, offset);
+		sg_unmark_end(sg);
+
 		ctx->sg_plaintext_num_elem++;
 
 		sk_mem_charge(sk, copy);