| Message ID | 1518186923-28650-1-git-send-email-alexey.kodanev@oracle.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net,v2] sctp: verify size of a new chunk in _sctp_make_chunk() | expand |
On Fri, Feb 09, 2018 at 05:35:23PM +0300, Alexey Kodanev wrote: > When SCTP makes INIT or INIT_ACK packet the total chunk length > can exceed SCTP_MAX_CHUNK_LEN which leads to kernel panic when > transmitting these packets, e.g. the crash on sending INIT_ACK: > > [ 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 becomes too big, mostly > because of the state cookie (INIT packet has large size with > many address parameters), plus additional server parameters. > > Later this chunk causes the panic in skb_put_data(): > > skb_packet_transmit() > sctp_packet_pack() > skb_put_data(nskb, chunk->skb->data, chunk->skb->len); > > 'nskb' (head skb) was previously allocated with packet->size > from u16 'chunk->chunk_hdr->length'. > > As suggested by Marcelo we should check the chunk's length in > _sctp_make_chunk() before trying to allocate skb for it and > discard a chunk if its size bigger than SCTP_MAX_CHUNK_LEN. > > Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leinter@gmail.com> Thanks Alexey. > --- > > v2: account for padding before checking chunklen > > net/sctp/sm_make_chunk.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > index 793b05e..d01475f 100644 > --- a/net/sctp/sm_make_chunk.c > +++ b/net/sctp/sm_make_chunk.c > @@ -1380,9 +1380,14 @@ static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc, > struct sctp_chunk *retval; > struct sk_buff *skb; > struct sock *sk; > + int chunklen; > + > + chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen); > + if (chunklen > SCTP_MAX_CHUNK_LEN) > + goto nodata; > > /* No need to allocate LL here, as this is only a chunk. */ > - skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp); > + skb = alloc_skb(chunklen, gfp); > if (!skb) > goto nodata; > > -- > 1.8.3.1 >
On Fri, Feb 09, 2018 at 05:35:23PM +0300, Alexey Kodanev wrote: > When SCTP makes INIT or INIT_ACK packet the total chunk length > can exceed SCTP_MAX_CHUNK_LEN which leads to kernel panic when > transmitting these packets, e.g. the crash on sending INIT_ACK: > > [ 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 becomes too big, mostly > because of the state cookie (INIT packet has large size with > many address parameters), plus additional server parameters. > > Later this chunk causes the panic in skb_put_data(): > > skb_packet_transmit() > sctp_packet_pack() > skb_put_data(nskb, chunk->skb->data, chunk->skb->len); > > 'nskb' (head skb) was previously allocated with packet->size > from u16 'chunk->chunk_hdr->length'. > > As suggested by Marcelo we should check the chunk's length in > _sctp_make_chunk() before trying to allocate skb for it and > discard a chunk if its size bigger than SCTP_MAX_CHUNK_LEN. > > Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> > --- > > v2: account for padding before checking chunklen > > net/sctp/sm_make_chunk.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > index 793b05e..d01475f 100644 > --- a/net/sctp/sm_make_chunk.c > +++ b/net/sctp/sm_make_chunk.c > @@ -1380,9 +1380,14 @@ static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc, > struct sctp_chunk *retval; > struct sk_buff *skb; > struct sock *sk; > + int chunklen; > + > + chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen); > + if (chunklen > SCTP_MAX_CHUNK_LEN) > + goto nodata; > > /* No need to allocate LL here, as this is only a chunk. */ > - skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp); > + skb = alloc_skb(chunklen, gfp); > if (!skb) > goto nodata; > > -- > 1.8.3.1 > > > Acked-by: Neil Horman <nhorman@tuxdriver.com>
From: Alexey Kodanev <alexey.kodanev@oracle.com> Date: Fri, 9 Feb 2018 17:35:23 +0300 > When SCTP makes INIT or INIT_ACK packet the total chunk length > can exceed SCTP_MAX_CHUNK_LEN which leads to kernel panic when > transmitting these packets, e.g. the crash on sending INIT_ACK: ... > Here the chunk size for INIT_ACK packet becomes too big, mostly > because of the state cookie (INIT packet has large size with > many address parameters), plus additional server parameters. > > Later this chunk causes the panic in skb_put_data(): > > skb_packet_transmit() > sctp_packet_pack() > skb_put_data(nskb, chunk->skb->data, chunk->skb->len); > > 'nskb' (head skb) was previously allocated with packet->size > from u16 'chunk->chunk_hdr->length'. > > As suggested by Marcelo we should check the chunk's length in > _sctp_make_chunk() before trying to allocate skb for it and > discard a chunk if its size bigger than SCTP_MAX_CHUNK_LEN. > > Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Applied and queued up for -stable, thanks.
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c index 793b05e..d01475f 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -1380,9 +1380,14 @@ static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc, struct sctp_chunk *retval; struct sk_buff *skb; struct sock *sk; + int chunklen; + + chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen); + if (chunklen > SCTP_MAX_CHUNK_LEN) + goto nodata; /* No need to allocate LL here, as this is only a chunk. */ - skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp); + skb = alloc_skb(chunklen, gfp); if (!skb) goto nodata;
When SCTP makes INIT or INIT_ACK packet the total chunk length can exceed SCTP_MAX_CHUNK_LEN which leads to kernel panic when transmitting these packets, e.g. the crash on sending INIT_ACK: [ 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 becomes too big, mostly because of the state cookie (INIT packet has large size with many address parameters), plus additional server parameters. Later this chunk causes the panic in skb_put_data(): skb_packet_transmit() sctp_packet_pack() skb_put_data(nskb, chunk->skb->data, chunk->skb->len); 'nskb' (head skb) was previously allocated with packet->size from u16 'chunk->chunk_hdr->length'. As suggested by Marcelo we should check the chunk's length in _sctp_make_chunk() before trying to allocate skb for it and discard a chunk if its size bigger than SCTP_MAX_CHUNK_LEN. Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> --- v2: account for padding before checking chunklen net/sctp/sm_make_chunk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)