tls: make sure to abort the stream if headers are bogus
Normally we wait for the socket to buffer up the whole record
before we service it. If the socket has a tiny buffer, however,
we read out the data sooner, to prevent connection stalls.
Make sure that we abort the connection when we find out late
that the record is actually invalid. Retrying the parsing is
fine in itself but since we copy some more data each time
before we parse we can overflow the allocated skb space.
Constructing a scenario in which we're under pressure without
enough data in the socket to parse the length upfront is quite
hard. syzbot figured out a way to do this by serving us the header
in small OOB sends, and then filling in the recvbuf with a large
normal send.
Make sure that tls_rx_msg_size() aborts strp, if we reach
an invalid record there's really no way to recover.
Reported-by: Lee Jones <lee@kernel.org>
Fixes: 84c61fe1a75b ("tls: rx: do not use the standard strparser")
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250917002814.1743558-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
BUG=b/446655675
TEST=presubmit
RELEASE_NOTE=Fixed KCTF-0aeb54a in the Linux Kernel.
cos-patch: security-high
Change-Id: Ifac6bfd9c784829643c2ffa674aa07c09c73e53e
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/111943
Reviewed-by: Kevin Berry <kpberry@google.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/112362
diff --git a/net/tls/tls.h b/net/tls/tls.h
index 5dc61c8..a3c5c5a 100644
--- a/net/tls/tls.h
+++ b/net/tls/tls.h
@@ -141,6 +141,7 @@ void update_sk_prot(struct sock *sk, struct tls_context *ctx);
int wait_on_pending_writer(struct sock *sk, long *timeo);
void tls_err_abort(struct sock *sk, int err);
+void tls_strp_abort_strp(struct tls_strparser *strp, int err);
int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx);
void tls_update_rx_zc_capable(struct tls_context *tls_ctx);
diff --git a/net/tls/tls_strp.c b/net/tls/tls_strp.c
index 6ce64a6..ae723cd 100644
--- a/net/tls/tls_strp.c
+++ b/net/tls/tls_strp.c
@@ -12,7 +12,7 @@
static struct workqueue_struct *tls_strp_wq;
-static void tls_strp_abort_strp(struct tls_strparser *strp, int err)
+void tls_strp_abort_strp(struct tls_strparser *strp, int err)
{
if (strp->stopped)
return;
@@ -210,11 +210,17 @@ static int tls_strp_copyin_frag(struct tls_strparser *strp, struct sk_buff *skb,
struct sk_buff *in_skb, unsigned int offset,
size_t in_len)
{
+ unsigned int nfrag = skb->len / PAGE_SIZE;
size_t len, chunk;
skb_frag_t *frag;
int sz;
- frag = &skb_shinfo(skb)->frags[skb->len / PAGE_SIZE];
+ if (unlikely(nfrag >= skb_shinfo(skb)->nr_frags)) {
+ DEBUG_NET_WARN_ON_ONCE(1);
+ return -EMSGSIZE;
+ }
+
+ frag = &skb_shinfo(skb)->frags[nfrag];
len = in_len;
/* First make sure we got the header */
@@ -519,10 +525,8 @@ static int tls_strp_read_sock(struct tls_strparser *strp)
tls_strp_load_anchor_with_queue(strp, inq);
if (!strp->stm.full_len) {
sz = tls_rx_msg_size(strp, strp->anchor);
- if (sz < 0) {
- tls_strp_abort_strp(strp, sz);
+ if (sz < 0)
return sz;
- }
strp->stm.full_len = sz;
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 27ce1fe..435235a 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2441,8 +2441,7 @@ int tls_rx_msg_size(struct tls_strparser *strp, struct sk_buff *skb)
return data_len + TLS_HEADER_SIZE;
read_failure:
- tls_err_abort(strp->sk, ret);
-
+ tls_strp_abort_strp(strp, ret);
return ret;
}
