tls: Correct length of scatterlist in tls_sw_sendpage

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 61f394d369bf..0a9b72fbd761 100644
--- 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);