diff options
| author | Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> | 2026-08-04 12:55:28 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-08-06 09:08:58 -0700 |
| commit | 1c8629651cb54f7b51db8fc0b1a9944e4a4b0f5e (patch) | |
| tree | 5f45195a198f5258ccfc0e59c54e724170e0252e /net | |
| parent | 1f042e426be08a1da57fa7841fd13eb6764f8f60 (diff) | |
tls: rx: restore msg_iter before TLS 1.3 optimistic retry
tls_decrypt_sg() advances msg->msg_iter when it maps user pages for
the optimistic TLS 1.3 zero-copy path. If the decrypted record turns
out not to be unpadded application data, tls_decrypt_sw() retries into
a kernel skb, but leaves the iterator advanced.
The subsequent copy from the skb then writes decrypted bytes again at
a later point in the caller iovecs while recvmsg() reports only the
post-retry length. A TLS peer can trigger this after the receiver
enables TLS_RX_EXPECT_NO_PAD.
Revert the iterator by the number of bytes consumed by the optimistic
mapping before retrying without zero-copy.
Add a selftest which sends a TLS 1.3 control record with
TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not
overwrite later iovecs beyond the returned length.
Fixes: ce61327ce989 ("tls: rx: support optimistic decrypt to user buffer with TLS 1.3")
Cc: stable@vger.kernel.org
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Link: https://patch.msgid.link/20260804125528.2139928-1-Jeremy.Jean@oss.cyber.gouv.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/tls/tls_sw.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index d2e399be8ef6..133ed7c89402 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1456,6 +1456,8 @@ tls_decrypt_sw(struct sock *sk, struct tls_context *tls_ctx, /* If opportunistic TLS 1.3 ZC failed retry without ZC */ if (unlikely(darg->zc && prot->version == TLS_1_3_VERSION && darg->tail != TLS_RECORD_TYPE_DATA)) { + iov_iter_revert(&msg->msg_iter, strp_msg(darg->skb)->full_len - + prot->overhead_size); darg->zc = false; if (!darg->tail) TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSRXNOPADVIOL); |