Re: [PATCH net] tls: Correct length of scatterlist in tls_sw_sendpage

[David Miller]

From: Dave Watson 
Date: Fri, 19 Jan 2018 12:30:13 -0800

> 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 

Applied, thanks Dave.

[PATCH net] tls: Correct length of scatterlist in tls_sw_sendpage

[Dave Watson]

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 
---
 net/tls/tls_sw.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 61f394d..0a9b72f 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -577,6 +577,8 @@ int tls_sw_sendpage(struct sock *sk, struct page *page,
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);
-- 
2.9.5