| Message ID | 20230902004841.614102-1-shaw.leon@gmail.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | apparmor: Fix null pointer deref when receiving skb during sock creation | expand |
On 9/1/23 17:48, Xiao Liang wrote: > The panic below is observed when receiving ICMP packets with secmark set > while an ICMP raw socket is being created. SK_CTX(sk)->label is updated > in apparmor_socket_post_create(), but the packet is delivered to the > socket before that, causing the null pointer dereference. > Drop the packet if label context is not set. > > BUG: kernel NULL pointer dereference, address: 000000000000004c > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP NOPTI > CPU: 0 PID: 407 Comm: a.out Not tainted 6.4.12-arch1-1 #1 3e6fa2753a2d75925c34ecb78e22e85a65d083df > Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/28/2020 > RIP: 0010:aa_label_next_confined+0xb/0x40 > Code: 00 00 48 89 ef e8 d5 25 0c 00 e9 66 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 89 f0 <8b> 77 4c 39 c6 7e 1f 48 63 d0 48 8d 14 d7 eb 0b 83 c0 01 48 83 c2 > RSP: 0018:ffffa92940003b08 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000000e > RDX: ffffa92940003be8 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffff8b57471e7800 R08: ffff8b574c642400 R09: 0000000000000002 > R10: ffffffffbd820eeb R11: ffffffffbeb7ff00 R12: ffff8b574c642400 > R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000 > FS: 00007fb092ea7640(0000) GS:ffff8b577bc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000000000004c CR3: 00000001020f2005 CR4: 00000000007706f0 > PKRU: 55555554 > Call Trace: > <IRQ> > ? __die+0x23/0x70 > ? page_fault_oops+0x171/0x4e0 > ? exc_page_fault+0x7f/0x180 > ? asm_exc_page_fault+0x26/0x30 > ? aa_label_next_confined+0xb/0x40 > apparmor_secmark_check+0xec/0x330 > security_sock_rcv_skb+0x35/0x50 > sk_filter_trim_cap+0x47/0x250 > sock_queue_rcv_skb_reason+0x20/0x60 > raw_rcv+0x13c/0x210 > raw_local_deliver+0x1f3/0x250 > ip_protocol_deliver_rcu+0x4f/0x2f0 > ip_local_deliver_finish+0x76/0xa0 > __netif_receive_skb_one_core+0x89/0xa0 > netif_receive_skb+0x119/0x170 > ? __netdev_alloc_skb+0x3d/0x140 > vmxnet3_rq_rx_complete+0xb23/0x1010 [vmxnet3 56a84f9c97178c57a43a24ec073b45a9d6f01f3a] > vmxnet3_poll_rx_only+0x36/0xb0 [vmxnet3 56a84f9c97178c57a43a24ec073b45a9d6f01f3a] > __napi_poll+0x28/0x1b0 > net_rx_action+0x2a4/0x380 > __do_softirq+0xd1/0x2c8 > __irq_exit_rcu+0xbb/0xf0 > common_interrupt+0x86/0xa0 > </IRQ> > <TASK> > asm_common_interrupt+0x26/0x40 > RIP: 0010:apparmor_socket_post_create+0xb/0x200 > Code: 08 48 85 ff 75 a1 eb b1 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 <55> 48 89 fd 53 45 85 c0 0f 84 b2 00 00 00 48 8b 1d 80 56 3f 02 48 > RSP: 0018:ffffa92940ce7e50 EFLAGS: 00000286 > RAX: ffffffffbc756440 RBX: 0000000000000000 RCX: 0000000000000001 > RDX: 0000000000000003 RSI: 0000000000000002 RDI: ffff8b574eaab740 > RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 > R10: ffff8b57444cec70 R11: 0000000000000000 R12: 0000000000000003 > R13: 0000000000000002 R14: ffff8b574eaab740 R15: ffffffffbd8e4748 > ? __pfx_apparmor_socket_post_create+0x10/0x10 > security_socket_post_create+0x4b/0x80 > __sock_create+0x176/0x1f0 > __sys_socket+0x89/0x100 > __x64_sys_socket+0x17/0x20 > do_syscall_64+0x5d/0x90 > ? do_syscall_64+0x6c/0x90 > ? do_syscall_64+0x6c/0x90 > ? do_syscall_64+0x6c/0x90 > entry_SYSCALL_64_after_hwframe+0x72/0xdc > > Fixes: ab9f2115081a ("apparmor: Allow filtering based on secmark policy") > Signed-off-by: Xiao Liang <shaw.leon@gmail.com> not sure how I dropped this one, thanks for the patch. I have pulled it into the apparmor tree Acked-by: John Johansen <john.johansen@canonical.com> > --- > security/apparmor/lsm.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c > index 108eccc5ada5..0dbff677ac2e 100644 > --- a/security/apparmor/lsm.c > +++ b/security/apparmor/lsm.c > @@ -1097,6 +1097,13 @@ static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) > if (!skb->secmark) > return 0; > > + /* > + * If reach here before socket_post_create hook is called, in which > + * case label is null, drop the packet. > + */ > + if (!ctx->label) > + return -EACCES; > + > return apparmor_secmark_check(ctx->label, OP_RECVMSG, AA_MAY_RECEIVE, > skb->secmark, sk); > }
On Mon, Oct 16, 2023 at 11:36 AM John Johansen <john.johansen@canonical.com> wrote: > > On 9/1/23 17:48, Xiao Liang wrote: > > The panic below is observed when receiving ICMP packets with secmark set > > while an ICMP raw socket is being created. SK_CTX(sk)->label is updated > > in apparmor_socket_post_create(), but the packet is delivered to the > > socket before that, causing the null pointer dereference. > > Drop the packet if label context is not set. > > not sure how I dropped this one, thanks for the patch. I have pulled it into the apparmor tree > I haven't seen this patch in the tree yet. May I know the status?
On 1/22/24 22:16, Xiao Liang wrote: > On Mon, Oct 16, 2023 at 11:36 AM John Johansen > <john.johansen@canonical.com> wrote: >> >> On 9/1/23 17:48, Xiao Liang wrote: >>> The panic below is observed when receiving ICMP packets with secmark set >>> while an ICMP raw socket is being created. SK_CTX(sk)->label is updated >>> in apparmor_socket_post_create(), but the packet is delivered to the >>> socket before that, causing the null pointer dereference. >>> Drop the packet if label context is not set. >> >> not sure how I dropped this one, thanks for the patch. I have pulled it into the apparmor tree >> > > I haven't seen this patch in the tree yet. May I know the status? sorry, this did get pulled in, but for some reason, didn't get promoted into apparmor-next I will try to send it up for -rc3
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 108eccc5ada5..0dbff677ac2e 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1097,6 +1097,13 @@ static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) if (!skb->secmark) return 0; + /* + * If reach here before socket_post_create hook is called, in which + * case label is null, drop the packet. + */ + if (!ctx->label) + return -EACCES; + return apparmor_secmark_check(ctx->label, OP_RECVMSG, AA_MAY_RECEIVE, skb->secmark, sk); }
The panic below is observed when receiving ICMP packets with secmark set while an ICMP raw socket is being created. SK_CTX(sk)->label is updated in apparmor_socket_post_create(), but the packet is delivered to the socket before that, causing the null pointer dereference. Drop the packet if label context is not set. BUG: kernel NULL pointer dereference, address: 000000000000004c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 407 Comm: a.out Not tainted 6.4.12-arch1-1 #1 3e6fa2753a2d75925c34ecb78e22e85a65d083df Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/28/2020 RIP: 0010:aa_label_next_confined+0xb/0x40 Code: 00 00 48 89 ef e8 d5 25 0c 00 e9 66 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 89 f0 <8b> 77 4c 39 c6 7e 1f 48 63 d0 48 8d 14 d7 eb 0b 83 c0 01 48 83 c2 RSP: 0018:ffffa92940003b08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000000e RDX: ffffa92940003be8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff8b57471e7800 R08: ffff8b574c642400 R09: 0000000000000002 R10: ffffffffbd820eeb R11: ffffffffbeb7ff00 R12: ffff8b574c642400 R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000 FS: 00007fb092ea7640(0000) GS:ffff8b577bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000004c CR3: 00000001020f2005 CR4: 00000000007706f0 PKRU: 55555554 Call Trace: <IRQ> ? __die+0x23/0x70 ? page_fault_oops+0x171/0x4e0 ? exc_page_fault+0x7f/0x180 ? asm_exc_page_fault+0x26/0x30 ? aa_label_next_confined+0xb/0x40 apparmor_secmark_check+0xec/0x330 security_sock_rcv_skb+0x35/0x50 sk_filter_trim_cap+0x47/0x250 sock_queue_rcv_skb_reason+0x20/0x60 raw_rcv+0x13c/0x210 raw_local_deliver+0x1f3/0x250 ip_protocol_deliver_rcu+0x4f/0x2f0 ip_local_deliver_finish+0x76/0xa0 __netif_receive_skb_one_core+0x89/0xa0 netif_receive_skb+0x119/0x170 ? __netdev_alloc_skb+0x3d/0x140 vmxnet3_rq_rx_complete+0xb23/0x1010 [vmxnet3 56a84f9c97178c57a43a24ec073b45a9d6f01f3a] vmxnet3_poll_rx_only+0x36/0xb0 [vmxnet3 56a84f9c97178c57a43a24ec073b45a9d6f01f3a] __napi_poll+0x28/0x1b0 net_rx_action+0x2a4/0x380 __do_softirq+0xd1/0x2c8 __irq_exit_rcu+0xbb/0xf0 common_interrupt+0x86/0xa0 </IRQ> <TASK> asm_common_interrupt+0x26/0x40 RIP: 0010:apparmor_socket_post_create+0xb/0x200 Code: 08 48 85 ff 75 a1 eb b1 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 <55> 48 89 fd 53 45 85 c0 0f 84 b2 00 00 00 48 8b 1d 80 56 3f 02 48 RSP: 0018:ffffa92940ce7e50 EFLAGS: 00000286 RAX: ffffffffbc756440 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000003 RSI: 0000000000000002 RDI: ffff8b574eaab740 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8b57444cec70 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000002 R14: ffff8b574eaab740 R15: ffffffffbd8e4748 ? __pfx_apparmor_socket_post_create+0x10/0x10 security_socket_post_create+0x4b/0x80 __sock_create+0x176/0x1f0 __sys_socket+0x89/0x100 __x64_sys_socket+0x17/0x20 do_syscall_64+0x5d/0x90 ? do_syscall_64+0x6c/0x90 ? do_syscall_64+0x6c/0x90 ? do_syscall_64+0x6c/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc Fixes: ab9f2115081a ("apparmor: Allow filtering based on secmark policy") Signed-off-by: Xiao Liang <shaw.leon@gmail.com> --- security/apparmor/lsm.c | 7 +++++++ 1 file changed, 7 insertions(+)