| From bippy-7c5fe7eed585 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-56664: bpf, sockmap: Fix race between element replace and close() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf, sockmap: Fix race between element replace and close() |
| |
| Element replace (with a socket different from the one stored) may race |
| with socket's close() link popping & unlinking. __sock_map_delete() |
| unconditionally unrefs the (wrong) element: |
| |
| // set map[0] = s0 |
| map_update_elem(map, 0, s0) |
| |
| // drop fd of s0 |
| close(s0) |
| sock_map_close() |
| lock_sock(sk) (s0!) |
| sock_map_remove_links(sk) |
| link = sk_psock_link_pop() |
| sock_map_unlink(sk, link) |
| sock_map_delete_from_link |
| // replace map[0] with s1 |
| map_update_elem(map, 0, s1) |
| sock_map_update_elem |
| (s1!) lock_sock(sk) |
| sock_map_update_common |
| psock = sk_psock(sk) |
| spin_lock(&stab->lock) |
| osk = stab->sks[idx] |
| sock_map_add_link(..., &stab->sks[idx]) |
| sock_map_unref(osk, &stab->sks[idx]) |
| psock = sk_psock(osk) |
| sk_psock_put(sk, psock) |
| if (refcount_dec_and_test(&psock)) |
| sk_psock_drop(sk, psock) |
| spin_unlock(&stab->lock) |
| unlock_sock(sk) |
| __sock_map_delete |
| spin_lock(&stab->lock) |
| sk = *psk // s1 replaced s0; sk == s1 |
| if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch |
| sk = xchg(psk, NULL) |
| if (sk) |
| sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle |
| psock = sk_psock(sk) |
| sk_psock_put(sk, psock) |
| if (refcount_dec_and_test()) |
| sk_psock_drop(sk, psock) |
| spin_unlock(&stab->lock) |
| release_sock(sk) |
| |
| Then close(map) enqueues bpf_map_free_deferred, which finally calls |
| sock_map_free(). This results in some refcount_t warnings along with |
| a KASAN splat [1]. |
| |
| Fix __sock_map_delete(), do not allow sock_map_unref() on elements that |
| may have been replaced. |
| |
| [1]: |
| BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330 |
| Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063 |
| |
| CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 |
| Workqueue: events_unbound bpf_map_free_deferred |
| Call Trace: |
| <TASK> |
| dump_stack_lvl+0x68/0x90 |
| print_report+0x174/0x4f6 |
| kasan_report+0xb9/0x190 |
| kasan_check_range+0x10f/0x1e0 |
| sock_map_free+0x10e/0x330 |
| bpf_map_free_deferred+0x173/0x320 |
| process_one_work+0x846/0x1420 |
| worker_thread+0x5b3/0xf80 |
| kthread+0x29e/0x360 |
| ret_from_fork+0x2d/0x70 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| |
| Allocated by task 1202: |
| kasan_save_stack+0x1e/0x40 |
| kasan_save_track+0x10/0x30 |
| __kasan_slab_alloc+0x85/0x90 |
| kmem_cache_alloc_noprof+0x131/0x450 |
| sk_prot_alloc+0x5b/0x220 |
| sk_alloc+0x2c/0x870 |
| unix_create1+0x88/0x8a0 |
| unix_create+0xc5/0x180 |
| __sock_create+0x241/0x650 |
| __sys_socketpair+0x1ce/0x420 |
| __x64_sys_socketpair+0x92/0x100 |
| do_syscall_64+0x93/0x180 |
| entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| |
| Freed by task 46: |
| kasan_save_stack+0x1e/0x40 |
| kasan_save_track+0x10/0x30 |
| kasan_save_free_info+0x37/0x60 |
| __kasan_slab_free+0x4b/0x70 |
| kmem_cache_free+0x1a1/0x590 |
| __sk_destruct+0x388/0x5a0 |
| sk_psock_destroy+0x73e/0xa50 |
| process_one_work+0x846/0x1420 |
| worker_thread+0x5b3/0xf80 |
| kthread+0x29e/0x360 |
| ret_from_fork+0x2d/0x70 |
| ret_from_fork_asm+0x1a/0x30 |
| |
| The buggy address belongs to the object at ffff88811f5b9080 |
| which belongs to the cache UNIX-STREAM of size 1984 |
| The buggy address is located 128 bytes inside of |
| freed 1984-byte region [ffff88811f5b9080, ffff88811f5b9840) |
| |
| The buggy address belongs to the physical page: |
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f5b8 |
| head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 |
| memcg:ffff888127d49401 |
| flags: 0x17ffffc0000040(head|node=0|zone=2|lastcpupid=0x1fffff) |
| page_type: f5(slab) |
| raw: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000 |
| raw: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401 |
| head: 0017ffffc0000040 ffff8881042e4500 dead000000000122 0000000000000000 |
| head: 0000000000000000 00000000800f000f 00000001f5000000 ffff888127d49401 |
| head: 0017ffffc0000003 ffffea00047d6e01 ffffffffffffffff 0000000000000000 |
| head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| Memory state around the buggy address: |
| ffff88811f5b9000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff88811f5b9080: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ^ |
| ffff88811f5b9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff88811f5b9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| Disabling lock debugging due to kernel taint |
| |
| refcount_t: addition on 0; use-after-free. |
| WARNING: CPU: 14 PID: 1063 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 |
| CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B 6.12.0+ #125 |
| Tainted: [B]=BAD_PAGE |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 |
| Workqueue: events_unbound bpf_map_free_deferred |
| RIP: 0010:refcount_warn_saturate+0xce/0x150 |
| Code: 34 73 eb 03 01 e8 82 53 ad fe 0f 0b eb b1 80 3d 27 73 eb 03 00 75 a8 48 c7 c7 80 bd 95 84 c6 05 17 73 eb 03 01 e8 62 53 ad fe <0f> 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 |
| RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282 |
| RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000 |
| RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001 |
| RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed10bcde6349 |
| R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000 |
| R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024 |
| FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0 |
| PKRU: 55555554 |
| Call Trace: |
| <TASK> |
| ? __warn.cold+0x5f/0x1ff |
| ? refcount_warn_saturate+0xce/0x150 |
| ? report_bug+0x1ec/0x390 |
| ? handle_bug+0x58/0x90 |
| ? exc_invalid_op+0x13/0x40 |
| ? asm_exc_invalid_op+0x16/0x20 |
| ? refcount_warn_saturate+0xce/0x150 |
| sock_map_free+0x2e5/0x330 |
| bpf_map_free_deferred+0x173/0x320 |
| process_one_work+0x846/0x1420 |
| worker_thread+0x5b3/0xf80 |
| kthread+0x29e/0x360 |
| ret_from_fork+0x2d/0x70 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| irq event stamp: 10741 |
| hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20 |
| hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770 |
| softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210 |
| softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210 |
| |
| refcount_t: underflow; use-after-free. |
| WARNING: CPU: 14 PID: 1063 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 |
| CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Tainted: G B W 6.12.0+ #125 |
| Tainted: [B]=BAD_PAGE, [W]=WARN |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 |
| Workqueue: events_unbound bpf_map_free_deferred |
| RIP: 0010:refcount_warn_saturate+0xee/0x150 |
| Code: 17 73 eb 03 01 e8 62 53 ad fe 0f 0b eb 91 80 3d 06 73 eb 03 00 75 88 48 c7 c7 e0 bd 95 84 c6 05 f6 72 eb 03 01 e8 42 53 ad fe <0f> 0b e9 6e ff ff ff 80 3d e6 72 eb 03 00 0f 85 61 ff ff ff 48 c7 |
| RSP: 0018:ffff88815c49fc70 EFLAGS: 00010282 |
| RAX: 0000000000000000 RBX: ffff88811f5b9100 RCX: 0000000000000000 |
| RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001 |
| RBP: 0000000000000003 R08: 0000000000000001 R09: ffffed10bcde6349 |
| R10: ffff8885e6f31a4b R11: 0000000000000000 R12: ffff88813be0b000 |
| R13: ffff88811f5b9100 R14: ffff88811f5b9080 R15: ffff88813be0b024 |
| FS: 0000000000000000(0000) GS:ffff8885e6f00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 000055dda99b0250 CR3: 000000015dbac000 CR4: 0000000000752ef0 |
| PKRU: 55555554 |
| Call Trace: |
| <TASK> |
| ? __warn.cold+0x5f/0x1ff |
| ? refcount_warn_saturate+0xee/0x150 |
| ? report_bug+0x1ec/0x390 |
| ? handle_bug+0x58/0x90 |
| ? exc_invalid_op+0x13/0x40 |
| ? asm_exc_invalid_op+0x16/0x20 |
| ? refcount_warn_saturate+0xee/0x150 |
| sock_map_free+0x2d3/0x330 |
| bpf_map_free_deferred+0x173/0x320 |
| process_one_work+0x846/0x1420 |
| worker_thread+0x5b3/0xf80 |
| kthread+0x29e/0x360 |
| ret_from_fork+0x2d/0x70 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| irq event stamp: 10741 |
| hardirqs last enabled at (10741): [<ffffffff84400ec6>] asm_sysvec_apic_timer_interrupt+0x16/0x20 |
| hardirqs last disabled at (10740): [<ffffffff811e532d>] handle_softirqs+0x60d/0x770 |
| softirqs last enabled at (10506): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210 |
| softirqs last disabled at (10301): [<ffffffff811e55a9>] __irq_exit_rcu+0x109/0x210 |
| |
| The Linux kernel CVE team has assigned CVE-2024-56664 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 5.10.236 with commit 6deb9e85dc9a2ba4414b91c1b5b00b8415910890 |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 5.15.180 with commit fdb2cd8957ac51f84c9e742ba866087944bb834b |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 6.1.125 with commit b79a0d1e9a374d1b376933a354c4fcd01fce0365 |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 6.6.67 with commit b015f19fedd2e12283a8450dd0aefce49ec57015 |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 6.12.6 with commit bf2318e288f636a882eea39f7e1015623629f168 |
| Issue introduced in 4.20 with commit 604326b41a6fb9b4a78b6179335decee0365cd8c and fixed in 6.13 with commit ed1fc5d76b81a4d681211333c026202cad4d5649 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-56664 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/core/sock_map.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/6deb9e85dc9a2ba4414b91c1b5b00b8415910890 |
| https://git.kernel.org/stable/c/fdb2cd8957ac51f84c9e742ba866087944bb834b |
| https://git.kernel.org/stable/c/b79a0d1e9a374d1b376933a354c4fcd01fce0365 |
| https://git.kernel.org/stable/c/b015f19fedd2e12283a8450dd0aefce49ec57015 |
| https://git.kernel.org/stable/c/bf2318e288f636a882eea39f7e1015623629f168 |
| https://git.kernel.org/stable/c/ed1fc5d76b81a4d681211333c026202cad4d5649 |
