[PATCH net v2] tls: fix RX desync on overlapping skbs
From: Maximilian Immanuel Brandtner <hidden>
Date: 2026-08-13 12:13:53
Subsystem:
networking [general], networking [tls], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, John Fastabend, Sabrina Dubroca, Linus Torvalds
The TCP receive queue can hold adjacent skbs whose sequence ranges
overlap. The tls fast-path reads the record header with skb_copy_bits()
by byte offset, which assumes skbs do not overlap, so a header split
across the overlap is misread and the connection aborts
(-EMSGSIZE/-EINVAL). tls_strp_check_queue_ok() detects such overlaps but
only ran after the header was parsed, never covering the header itself.
Observed with parallel kTLS connections on:
- ConnectX-7 + IPsec crypto offload + GRO
- VirtIO (8 queues) + GRO
Fixes: 84c61fe1a75b ("tls: rx: do not use the standard strparser")
Signed-off-by: Maximilian Immanuel Brandtner <redacted>
---
v2:
- move the stm.offset addition into tls_strp_check_queue_ok()
No functional change from v1
Tested on Linux kernel 7.2-rc6
---
net/tls/tls_strp.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/net/tls/tls_strp.c b/net/tls/tls_strp.c
index 61b10c697ecc..6cc222008d95 100644
--- a/net/tls/tls_strp.c
+++ b/net/tls/tls_strp.c@@ -430,9 +430,10 @@ static int tls_strp_read_copy(struct tls_strparser *strp, bool qshort) return 0; } -static bool tls_strp_check_queue_ok(struct tls_strparser *strp) +static bool tls_strp_check_queue_ok(struct tls_strparser *strp, + unsigned int len) { - unsigned int len = strp->stm.offset + strp->stm.full_len; + unsigned int remaining = strp->stm.offset + len; struct sk_buff *first, *skb; u32 seq;
@@ -443,9 +444,9 @@ static bool tls_strp_check_queue_ok(struct tls_strparser *strp) /* Make sure there's no duplicate data in the queue, * and the decrypted status matches. */ - while (skb->len < len) { + while (skb->len < remaining) { seq += skb->len; - len -= skb->len; + remaining -= skb->len; skb = skb->next; if (TCP_SKB_CB(skb)->seq != seq)
@@ -525,6 +526,11 @@ static int tls_strp_read_sock(struct tls_strparser *strp) tls_strp_load_anchor_with_queue(strp, inq); if (!strp->stm.full_len) { + if (inq < TLS_HEADER_SIZE) + return tls_strp_read_copy(strp, true); + if (!tls_strp_check_queue_ok(strp, TLS_HEADER_SIZE)) + return tls_strp_read_copy(strp, false); + sz = tls_rx_msg_size(strp, strp->anchor); if (sz < 0) return sz;
@@ -535,7 +541,7 @@ static int tls_strp_read_sock(struct tls_strparser *strp) return tls_strp_read_copy(strp, true); } - if (!tls_strp_check_queue_ok(strp)) + if (!tls_strp_check_queue_ok(strp, strp->stm.full_len)) return tls_strp_read_copy(strp, false); WRITE_ONCE(strp->msg_ready, 1);
--
2.55.0