bpf, ktls: Fix data corruption when using bpf_msg_pop_data() in ktls

[ Upstream commit 178f6a5c8cb3b6be1602de0964cd440243f493c9 ]

When sending plaintext data, we initially calculated the corresponding
ciphertext length. However, if we later reduced the plaintext data length
via socket policy, we failed to recalculate the ciphertext length.

This results in transmitting buffers containing uninitialized data during
ciphertext transmission.

This causes uninitialized bytes to be appended after a complete
"Application Data" packet, leading to errors on the receiving end when
parsing TLS record.

BUG=b/440034096
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2025-38608 in the Linux kernel.

cos-patch: security-moderate
Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling")
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Change-Id: I2a941dc5cf7fcde9e80a389c5938357e7c170e96
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/bpf/20250609020910.397930-2-jiayuan.chen@linux.dev
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/111093
Reviewed-by: Chenglong Tang <chenglongtang@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
1 file changed