Syzbot reported skb_over_panic() in llc_pdu_init_as_xid_cmd(). The
problem was in wrong LCC header manipulations.
Syzbot's reproducer tries to send XID packet. llc_ui_sendmsg() is
doing following steps:
1. skb allocation with size = len + header size
len is passed from userpace and header size
is 3 since addr->sllc_xid is set.
2. skb_reserve() for header_len = 3
3. filling all other space with memcpy_from_msg()
Ok, at this moment we have fully loaded skb, only headers needs to be
filled.
Then code comes to llc_sap_action_send_xid_c(). This function pushes 3
bytes for LLC PDU header and initializes it. Then comes
llc_pdu_init_as_xid_cmd(). It initalizes next 3 bytes *AFTER* LLC PDU
header and call skb_push(skb, 3). This looks wrong for 2 reasons:
1. Bytes rigth after LLC header are user data, so this function
was overwriting payload.
2. skb_push(skb, 3) call can cause skb_over_panic() since
all free space was filled in llc_ui_sendmsg(). (This can
happen is user passed 686 len: 686 + 14 (eth header) + 3 (LLC
header) = 703. SKB_DATA_ALIGN(703) = 704)
So, in this patch I added 2 new private constansts: LLC_PDU_TYPE_U_XID
and LLC_PDU_LEN_U_XID. LLC_PDU_LEN_U_XID is used to correctly reserve
header size to handle LLC + XID case. LLC_PDU_TYPE_U_XID is used by
llc_pdu_header_init() function to push 6 bytes instead of 3. And finally
I removed skb_push() call from llc_pdu_init_as_xid_cmd().
This changes should not affect other parts of LLC, since after
all steps we just transmit buffer.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5e5a981ad7cc54c4b2b4@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix the following make W=1 kernel build warning:
net/llc/llc_s_ac.c:38: warning: expecting prototype for llc_sap_action_unit_data_ind(). Prototype was for llc_sap_action_unitdata_ind() instead
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
syzbot reported:
BUG: memory leak
unreferenced object 0xffff888116270800 (size 224):
comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 20 e1 2a 81 88 ff ff 00 40 3d 2a 81 88 ff ff . .*.....@=*....
backtrace:
[<000000004d41b4cc>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
[<000000004d41b4cc>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<000000004d41b4cc>] slab_alloc_node mm/slab.c:3269 [inline]
[<000000004d41b4cc>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
[<00000000506a5965>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
[<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
[<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250 net/core/skbuff.c:5327
[<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0 net/core/sock.c:2225
[<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
[<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
[<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
[<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
[<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
[...]
The bug is that llc_sap_state_process() always takes an extra reference
to the skb, but sometimes neither llc_sap_next_state() nor
llc_sap_state_process() itself drops this reference.
Fix it by changing llc_sap_next_state() to never consume a reference to
the skb, rather than sometimes do so and sometimes not. Then remove the
extra skb_get() and kfree_skb() from llc_sap_state_process().
Reported-by: syzbot+6bf095f9becf5efef645@syzkaller.appspotmail.com
Reported-by: syzbot+31c16aa4202dace3812e@syzkaller.appspotmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Allocate the skb for llc responses with the received packet size by
using the size adjustable llc_frame_alloc.
Don't allocate useless extra payload.
Cleanup magic numbers.
So, this fixes oops.
Reported by Jim Westfall:
kernel: skb_over_panic: text:c0541fc7 len:1000 put:997 head:c166ac00 data:c166ac2f tail:0xc166b017 end:0xc166ac80 dev:eth0
kernel: ------------[ cut here ]------------
kernel: kernel BUG at net/core/skbuff.c:95!
Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cleanup of LLC. llc_mac_hdr_init can take constant arguments,
and it is defined twice once in llc_output.h that is otherwise unused.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Acked-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Borrowing the structure of TCP/IP for this. On the receive of new connections I
was bh_lock_socking the _new_ sock, not the listening one, duh, now it survives
the ssh connections storm I've been using to test this specific bug.
Also fixes send side skb sock accounting.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
So as to set the newly created sk_buff ->dev member with it, that way we stop
using dev_base->next, that is the wrong thing to do, as there may well be
several interfaces being used with LLC. This was not such a big problem after
all as most of the users of llc_alloc_frame were setting the correct dev, but
this way code is reduced.
This also fixes another bug in llc_station_ac_send_null_dsap_xid_c, that was
not setting the skb->dev field.
Signed-off-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Pavel Skripkin