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| author | Xiang Mei (Microsoft) <xmei5@asu.edu> | 2026-07-10 23:07:24 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-21 15:02:29 -0700 |
| commit | cd170f051dba9ac146fabcd1b91726487c0cb9fa (patch) | |
| tree | b1c177e61bb58220185313c2ea35889a145e1046 /drivers/net/gtp.c | |
| parent | e5f9476960085496533420eb59d70a2bef7e1d60 (diff) | |
| download | linux-next-cd170f051dba9ac146fabcd1b91726487c0cb9fa.tar.gz linux-next-cd170f051dba9ac146fabcd1b91726487c0cb9fa.zip | |
gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its
caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +
gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For
a 16-19 byte echo request the pull fails and returns NULL without
advancing skb->data; execution continues, and the following skb_push()
plus the IP header pushed by iptunnel_xmit() move skb->data below
skb->head, tripping skb_under_panic().
Fix it by dropping the packet when skb_pull_data() fails.
skbuff: skb_under_panic: ...
kernel BUG at net/core/skbuff.c:214!
Call Trace:
skb_push (net/core/skbuff.c:2648)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)
gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)
udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)
...
Kernel panic - not syncing: Fatal exception in interrupt
Fixes: 9af41cc33471 ("gtp: Implement GTP echo response")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Link: https://patch.msgid.link/20260710230724.942574-1-xmei5@asu.edu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/gtp.c')
| -rw-r--r-- | drivers/net/gtp.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index c0e38878af51..9a12cc53da00 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -669,8 +669,9 @@ static int gtp1u_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) return -1; /* pull GTP and UDP headers */ - skb_pull_data(skb, - sizeof(struct gtp1_header_long) + sizeof(struct udphdr)); + if (!skb_pull_data(skb, sizeof(struct gtp1_header_long) + + sizeof(struct udphdr))) + return -1; gtp_pkt = skb_push(skb, sizeof(struct gtp1u_packet)); memset(gtp_pkt, 0, sizeof(struct gtp1u_packet)); |