[PATCH net] net: tls: fix device-offloaded sendpage straddling records

[Jakub Kicinski <kuba@kernel.org>]

Adrien reports that incorrect data is transmitted when a single
page straddles multiple records. We would transmit the same
data in all iterations of the loop.

Reported-by: Adrien Moulin <amoulin@corp.free.fr>
Link: https://lore.kernel.org/all/61481278.42813558.1677845235112.JavaMail.zimbra@corp.free.fr
Fixes: c1318b39c7d3 ("tls: Add opt-in zerocopy mode of sendfile()")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: borisp@nvidia.com
CC: john.fastabend@gmail.com
CC: tariqt@nvidia.com
CC: maximmi@nvidia.com
CC: maxtram95@gmail.com

Adrien, would you mind sending an official Tested-by: tag
in reply to this patch?

Maxim, can I add a .mailmap entry for you? get_maintainers
will complain if I don't CC your @nvidia address :(
---
 net/tls/tls_device.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 6c593788dc25..a7cc4f9faac2 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -508,6 +508,8 @@ static int tls_push_data(struct sock *sk,
 			zc_pfrag.offset = iter_offset.offset;
 			zc_pfrag.size = copy;
 			tls_append_frag(record, &zc_pfrag, copy);
+
+			iter_offset.offset += copy;
 		} else if (copy) {
 			copy = min_t(size_t, copy, pfrag->size - pfrag->offset);
 
-- 
2.39.2