From: Davide Caratti dcaratti@redhat.com
[ Upstream commit f67169fef8dbcc1ac6a6a109ecaad0d3b259002c ]
when configuring act_pedit rules, the number of keys is validated only on addition of a new entry. This is not sufficient to avoid hitting a WARN() in the traffic path: for example, it is possible to replace a valid entry with a new one having 0 extended keys, thus causing splats in dmesg like:
pedit BUG: index 42 WARNING: CPU: 2 PID: 4054 at net/sched/act_pedit.c:410 tcf_pedit_act+0xc84/0x1200 [act_pedit] [...] RIP: 0010:tcf_pedit_act+0xc84/0x1200 [act_pedit] Code: 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e ac 00 00 00 48 8b 44 24 10 48 c7 c7 a0 c4 e4 c0 8b 70 18 e8 1c 30 95 ea <0f> 0b e9 a0 fa ff ff e8 00 03 f5 ea e9 14 f4 ff ff 48 89 58 40 e9 RSP: 0018:ffff888077c9f320 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffffac2983a2 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888053927bec RBP: dffffc0000000000 R08: ffffed100a726209 R09: ffffed100a726209 R10: 0000000000000001 R11: ffffed100a726208 R12: ffff88804beea780 R13: ffff888079a77400 R14: ffff88804beea780 R15: ffff888027ab2000 FS: 00007fdeec9bd740(0000) GS:ffff888053900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdb3dfd000 CR3: 000000004adb4006 CR4: 00000000001606e0 Call Trace: tcf_action_exec+0x105/0x3f0 tcf_classify+0xf2/0x410 __dev_queue_xmit+0xcbf/0x2ae0 ip_finish_output2+0x711/0x1fb0 ip_output+0x1bf/0x4b0 ip_send_skb+0x37/0xa0 raw_sendmsg+0x180c/0x2430 sock_sendmsg+0xdb/0x110 __sys_sendto+0x257/0x2b0 __x64_sys_sendto+0xdd/0x1b0 do_syscall_64+0xa5/0x4e0 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fdeeb72e993 Code: 48 8b 0d e0 74 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 0d d6 2c 00 00 75 13 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 4b cc 00 00 48 89 04 24 RSP: 002b:00007ffdb3de8a18 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055c81972b700 RCX: 00007fdeeb72e993 RDX: 0000000000000040 RSI: 000055c81972b700 RDI: 0000000000000003 RBP: 00007ffdb3dea130 R08: 000055c819728510 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040 R13: 000055c81972b6c0 R14: 000055c81972969c R15: 0000000000000080
Fix this moving the check on 'nkeys' earlier in tcf_pedit_init(), so that attempts to install rules having 0 keys are always rejected with -EINVAL.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Davide Caratti dcaratti@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_pedit.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/net/sched/act_pedit.c +++ b/net/sched/act_pedit.c @@ -46,7 +46,7 @@ static struct tcf_pedit_key_ex *tcf_pedi int err = -EINVAL; int rem;
- if (!nla || !n) + if (!nla) return NULL;
keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL); @@ -163,6 +163,9 @@ static int tcf_pedit_init(struct net *ne return -EINVAL;
parm = nla_data(pattr); + if (!parm->nkeys) + return -EINVAL; + ksize = parm->nkeys * sizeof(struct tc_pedit_key); if (nla_len(pattr) < sizeof(*parm) + ksize) return -EINVAL; @@ -172,8 +175,6 @@ static int tcf_pedit_init(struct net *ne return PTR_ERR(keys_ex);
if (!tcf_idr_check(tn, parm->index, a, bind)) { - if (!parm->nkeys) - return -EINVAL; ret = tcf_idr_create(tn, parm->index, est, a, &act_pedit_ops, bind, false); if (ret)