RFE: allow self in typetransition for anon_inode transitions #59
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Hi @doveride, I'm going to close this out as I think this is a policy language and/or compiler issue as the kernel generally doesn't have the concept of "self" with respect to access controls decisions. FWIW, the kernel is definitely using the same value for the subject and object in the isec->sclass = SECCLASS_ANON_INODE;
rc = security_transition_sid(
&selinux_state, tsec->sid, tsec->sid,
isec->sclass, name, &isec->sid);
if (rc)
return rc; |
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FWIW, I started working on adding this support to SELinux userspace last year, but haven't had time to finish it. It's near the top of my TODO list, but no ETA yet, sorry... |
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Thanks @WOnder93, is it worth creating an issue in the GH userspace repo to track this? |
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@pcmoore Sorry, I forgot to reply here... Anyway, in the meantime the support has been added to SELinux userspace with these commits: |
pcmoore
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Jul 10, 2023
l2cap_sock_release(sk) frees sk. However, sk's children are still alive and point to the already free'd sk's address. To fix this, l2cap_sock_release(sk) also cleans sk's children. ================================================================== BUG: KASAN: use-after-free in l2cap_sock_ready_cb+0xb7/0x100 net/bluetooth/l2cap_sock.c:1650 Read of size 8 at addr ffff888104617aa8 by task kworker/u3:0/276 CPU: 0 PID: 276 Comm: kworker/u3:0 Not tainted 6.2.0-00001-gef397bd4d5fb-dirty #59 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci2 hci_rx_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x72/0x95 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:306 [inline] print_report+0x175/0x478 mm/kasan/report.c:417 kasan_report+0xb1/0x130 mm/kasan/report.c:517 l2cap_sock_ready_cb+0xb7/0x100 net/bluetooth/l2cap_sock.c:1650 l2cap_chan_ready+0x10e/0x1e0 net/bluetooth/l2cap_core.c:1386 l2cap_config_req+0x753/0x9f0 net/bluetooth/l2cap_core.c:4480 l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5739 [inline] l2cap_sig_channel net/bluetooth/l2cap_core.c:6509 [inline] l2cap_recv_frame+0xe2e/0x43c0 net/bluetooth/l2cap_core.c:7788 l2cap_recv_acldata+0x6ed/0x7e0 net/bluetooth/l2cap_core.c:8506 hci_acldata_packet net/bluetooth/hci_core.c:3813 [inline] hci_rx_work+0x66e/0xbc0 net/bluetooth/hci_core.c:4048 process_one_work+0x4ea/0x8e0 kernel/workqueue.c:2289 worker_thread+0x364/0x8e0 kernel/workqueue.c:2436 kthread+0x1b9/0x200 kernel/kthread.c:376 ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308 </TASK> Allocated by task 288: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x82/0x90 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:968 [inline] __kmalloc+0x5a/0x140 mm/slab_common.c:981 kmalloc include/linux/slab.h:584 [inline] sk_prot_alloc+0x113/0x1f0 net/core/sock.c:2040 sk_alloc+0x36/0x3c0 net/core/sock.c:2093 l2cap_sock_alloc.constprop.0+0x39/0x1c0 net/bluetooth/l2cap_sock.c:1852 l2cap_sock_create+0x10d/0x220 net/bluetooth/l2cap_sock.c:1898 bt_sock_create+0x183/0x290 net/bluetooth/af_bluetooth.c:132 __sock_create+0x226/0x380 net/socket.c:1518 sock_create net/socket.c:1569 [inline] __sys_socket_create net/socket.c:1606 [inline] __sys_socket_create net/socket.c:1591 [inline] __sys_socket+0x112/0x200 net/socket.c:1639 __do_sys_socket net/socket.c:1652 [inline] __se_sys_socket net/socket.c:1650 [inline] __x64_sys_socket+0x40/0x50 net/socket.c:1650 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3f/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc Freed by task 288: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:523 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free mm/kasan/common.c:200 [inline] __kasan_slab_free+0x10a/0x190 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook mm/slub.c:1807 [inline] slab_free mm/slub.c:3787 [inline] __kmem_cache_free+0x88/0x1f0 mm/slub.c:3800 sk_prot_free net/core/sock.c:2076 [inline] __sk_destruct+0x347/0x430 net/core/sock.c:2168 sk_destruct+0x9c/0xb0 net/core/sock.c:2183 __sk_free+0x82/0x220 net/core/sock.c:2194 sk_free+0x7c/0xa0 net/core/sock.c:2205 sock_put include/net/sock.h:1991 [inline] l2cap_sock_kill+0x256/0x2b0 net/bluetooth/l2cap_sock.c:1257 l2cap_sock_release+0x1a7/0x220 net/bluetooth/l2cap_sock.c:1428 __sock_release+0x80/0x150 net/socket.c:650 sock_close+0x19/0x30 net/socket.c:1368 __fput+0x17a/0x5c0 fs/file_table.c:320 task_work_run+0x132/0x1c0 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x113/0x120 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x21/0x50 kernel/entry/common.c:296 do_syscall_64+0x4c/0x90 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x72/0xdc The buggy address belongs to the object at ffff888104617800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 680 bytes inside of 1024-byte region [ffff888104617800, ffff888104617c00) The buggy address belongs to the physical page: page:00000000dbca6a80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888104614000 pfn:0x104614 head:00000000dbca6a80 order:2 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0 flags: 0x200000000010200(slab|head|node=0|zone=2) raw: 0200000000010200 ffff888100041dc0 ffffea0004212c10 ffffea0004234b10 raw: ffff888104614000 0000000000080002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888104617980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888104617a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888104617a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888104617b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888104617b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Ack: This bug is found by FuzzBT with a modified Syzkaller. Other contributors are Ruoyu Wu and Hui Peng. Signed-off-by: Sungwoo Kim <[email protected]> Signed-off-by: Luiz Augusto von Dentz <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
stephensmalley
pushed a commit
to stephensmalley/selinux-kernel
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May 15, 2024
Christoph reported a splat hinting at a corrupted snd_una: WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Modules linked in: CPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 SELinuxProject#59 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Code: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8 8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe <0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9 RSP: 0018:ffffc9000013fd48 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4 RDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000 R13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000 FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0 Call Trace: <TASK> __mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 [inline] mptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline] __mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615 mptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767 process_one_work+0x1e0/0x560 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x3c7/0x640 kernel/workqueue.c:3416 kthread+0x121/0x170 kernel/kthread.c:388 ret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 </TASK> When fallback to TCP happens early on a client socket, snd_nxt is not yet initialized and any incoming ack will copy such value into snd_una. If the mptcp worker (dumbly) tries mptcp-level re-injection after such ack, that would unconditionally trigger a send buffer cleanup using 'bad' snd_una values. We could easily disable re-injection for fallback sockets, but such dumb behavior already helped catching a few subtle issues and a very low to zero impact in practice. Instead address the issue always initializing snd_nxt (and write_seq, for consistency) at connect time. Fixes: 8fd7380 ("mptcp: fallback in case of simultaneous connect") Cc: [email protected] Reported-by: Christoph Paasch <[email protected]> Closes: multipath-tcp/mptcp_net-next#485 Tested-by: Christoph Paasch <[email protected]> Signed-off-by: Paolo Abeni <[email protected]> Reviewed-by: Mat Martineau <[email protected]> Signed-off-by: Matthieu Baerts (NGI0) <[email protected]> Link: https://lore.kernel.org/r/20240429-upstream-net-20240429-mptcp-snd_nxt-init-connect-v1-1-59ceac0a7dcb@kernel.org Signed-off-by: Jakub Kicinski <[email protected]>
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anon_inode transitions happen on self/create but the typetransition statement does not accept self.
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