From: Sam Swicegood <samswicegood@gmail.com>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
horms@kernel.org, kuniyu@google.com,
Sam Swicegood <sam@gib.games>
Subject: [PATCH] nfc: llcp: check skb tailroom before appending TLV
Date: Wed, 18 Feb 2026 16:45:31 -0500 [thread overview]
Message-ID: <20260218214550.53342-1-sam@gib.games> (raw)
llcp_add_tlv() appends TLV data to an skb using skb_put_data()
without first verifying that sufficient tailroom is available.
Add a tailroom check to avoid writing past end of the skb when
building LLCP PDUs.
Signed-off-by: Sam Swicegood <sam@gib.games>
---
net/nfc/llcp_commands.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/nfc/llcp_commands.c b/net/nfc/llcp_commands.c
index b652323bc2c1..10acc5da954f 100644
--- a/net/nfc/llcp_commands.c
+++ b/net/nfc/llcp_commands.c
@@ -300,9 +300,10 @@ static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, const u8 *tlv,
u8 tlv_length)
{
- /* XXX Add an skb length check */
+ if (!pdu || !tlv)
+ return NULL;
- if (tlv == NULL)
+ if (skb_tailroom(pdu) < tlv_length)
return NULL;
skb_put_data(pdu, tlv, tlv_length);
--
2.43.0
next reply other threads:[~2026-02-18 21:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-18 21:45 Sam Swicegood [this message]
2026-02-18 22:06 ` [PATCH] nfc: llcp: check skb tailroom before appending TLV Kuniyuki Iwashima
2026-02-18 22:34 ` Sam Swicegood
2026-02-19 1:15 ` Kuniyuki Iwashima
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