Hi,
Got the following panic when the received INIT packet has a lot of
address parameters, so that the INIT_ACK chunksize exceeds
SCTP_MAX_CHUNK_LEN:
[ 597.804948] skbuff: skb_over_panic: text:00000000ffae06e4 len:120168 put:120156
head:000000007aa47635 data:00000000d991c2de tail:0x1d640 end:0xfec0 dev:<NULL>
...
[ 597.976970] ------------[ cut here ]------------
[ 598.033408] kernel BUG at net/core/skbuff.c:104!
[ 600.314841] Call Trace:
[ 600.345829] <IRQ>
[ 600.371639] ? sctp_packet_transmit+0x2095/0x26d0 [sctp]
[ 600.436934] skb_put+0x16c/0x200
[ 600.477295] sctp_packet_transmit+0x2095/0x26d0 [sctp]
[ 600.540630] ? sctp_packet_config+0x890/0x890 [sctp]
[ 600.601781] ? __sctp_packet_append_chunk+0x3b4/0xd00 [sctp]
[ 600.671356] ? sctp_cmp_addr_exact+0x3f/0x90 [sctp]
[ 600.731482] sctp_outq_flush+0x663/0x30d0 [sctp]
[ 600.788565] ? sctp_make_init+0xbf0/0xbf0 [sctp]
[ 600.845555] ? sctp_check_transmitted+0x18f0/0x18f0 [sctp]
[ 600.912945] ? sctp_outq_tail+0x631/0x9d0 [sctp]
[ 600.969936] sctp_cmd_interpreter.isra.22+0x3be1/0x5cb0 [sctp]
[ 601.041593] ? sctp_sf_do_5_1B_init+0x85f/0xc30 [sctp]
[ 601.104837] ? sctp_generate_t1_cookie_event+0x20/0x20 [sctp]
[ 601.175436] ? sctp_eat_data+0x1710/0x1710 [sctp]
[ 601.233575] sctp_do_sm+0x182/0x560 [sctp]
[ 601.284328] ? sctp_has_association+0x70/0x70 [sctp]
[ 601.345586] ? sctp_rcv+0xef4/0x32f0 [sctp]
[ 601.397478] ? sctp6_rcv+0xa/0x20 [sctp]
...
Here the chunk size for INIT_ACK packet may become too big, mostly
because of the cookielen. Tried on local machine so both addrlen
and cookielen was big: addrlen 39960 cookielen 80168.
Not sure how to fix it correctly, may be we need a check here
or add it to sctp_make_control()?
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 793b05e..c27564c 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -475,6 +475,9 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
if (num_ext)
chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
+ if (chunksize > SCTP_MAX_CHUNK_LEN)
+ goto nomem_chunk;
+
/* Now allocate and fill out the chunk. */
retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
if (!retval)
And for INIT as well...
Otherwise this chunk goes to skb_packet_transmit() -> sctp_packet_pack()
where panic on
skb_put_data(nskb, chunk->skb->data, chunk->skb->len);
nskb (head skb) was previously allocated with packet->size that looks
like getting the chunk size from u16 chunk_hdr->length.
Thanks,
Alexey
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