CVE-2024-27398

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: Fix use-after-free bugs caused by sco_sock_timeout

When the sco connection is established and then, the sco socket is releasing, timeout_work will be scheduled to judge whether the sco disconnection is timeout. The sock will be deallocated later, but it is dereferenced again in sco_sock_timeout. As a result, the use-after-free bugs will happen. The root cause is shown below:

Cleanup Thread               |      Worker Thread

sco_sock_release | sco_sock_close | __sco_sock_close | sco_sock_set_timer | schedule_delayed_work | sco_sock_kill | (wait a time) sock_put(sk) //FREE | sco_sock_timeout | sock_hold(sk) //USE

The KASAN report triggered by POC is shown below:

[ 95.890016] ================================================================== [ 95.890496] BUG: KASAN: slab-use-after-free in sco_sock_timeout+0x5e/0x1c0 [ 95.890755] Write of size 4 at addr ffff88800c388080 by task kworker/0:0/7 … [ 95.890755] Workqueue: events sco_sock_timeout [ 95.890755] Call Trace: [ 95.890755] [ 95.890755] dump_stack_lvl+0x45/0x110 [ 95.890755] print_address_description+0x78/0x390 [ 95.890755] print_report+0x11b/0x250 [ 95.890755] ? __virt_addr_valid+0xbe/0xf0 [ 95.890755] ? sco_sock_timeout+0x5e/0x1c0 [ 95.890755] kasan_report+0x139/0x170 [ 95.890755] ? update_load_avg+0xe5/0x9f0 [ 95.890755] ? sco_sock_timeout+0x5e/0x1c0 [ 95.890755] kasan_check_range+0x2c3/0x2e0 [ 95.890755] sco_sock_timeout+0x5e/0x1c0 [ 95.890755] process_one_work+0x561/0xc50 [ 95.890755] worker_thread+0xab2/0x13c0 [ 95.890755] ? pr_cont_work+0x490/0x490 [ 95.890755] kthread+0x279/0x300 [ 95.890755] ? pr_cont_work+0x490/0x490 [ 95.890755] ? kthread_blkcg+0xa0/0xa0 [ 95.890755] ret_from_fork+0x34/0x60 [ 95.890755] ? kthread_blkcg+0xa0/0xa0 [ 95.890755] ret_from_fork_asm+0x11/0x20 [ 95.890755] [ 95.890755] [ 95.890755] Allocated by task 506: [ 95.890755] kasan_save_track+0x3f/0x70 [ 95.890755] __kasan_kmalloc+0x86/0x90 [ 95.890755] __kmalloc+0x17f/0x360 [ 95.890755] sk_prot_alloc+0xe1/0x1a0 [ 95.890755] sk_alloc+0x31/0x4e0 [ 95.890755] bt_sock_alloc+0x2b/0x2a0 [ 95.890755] sco_sock_create+0xad/0x320 [ 95.890755] bt_sock_create+0x145/0x320 [ 95.890755] __sock_create+0x2e1/0x650 [ 95.890755] __sys_socket+0xd0/0x280 [ 95.890755] __x64_sys_socket+0x75/0x80 [ 95.890755] do_syscall_64+0xc4/0x1b0 [ 95.890755] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 95.890755] [ 95.890755] Freed by task 506: [ 95.890755] kasan_save_track+0x3f/0x70 [ 95.890755] kasan_save_free_info+0x40/0x50 [ 95.890755] poison_slab_object+0x118/0x180 [ 95.890755] __kasan_slab_free+0x12/0x30 [ 95.890755] kfree+0xb2/0x240 [ 95.890755] __sk_destruct+0x317/0x410 [ 95.890755] sco_sock_release+0x232/0x280 [ 95.890755] sock_close+0xb2/0x210 [ 95.890755] __fput+0x37f/0x770 [ 95.890755] task_work_run+0x1ae/0x210 [ 95.890755] get_signal+0xe17/0xf70 [ 95.890755] arch_do_signal_or_restart+0x3f/0x520 [ 95.890755] syscall_exit_to_user_mode+0x55/0x120 [ 95.890755] do_syscall_64+0xd1/0x1b0 [ 95.890755] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 95.890755] [ 95.890755] The buggy address belongs to the object at ffff88800c388000 [ 95.890755] which belongs to the cache kmalloc-1k of size 1024 [ 95.890755] The buggy address is located 128 bytes inside of [ 95.890755] freed 1024-byte region [ffff88800c388000, ffff88800c388400) [ 95.890755] [ 95.890755] The buggy address belongs to the physical page: [ 95.890755] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88800c38a800 pfn:0xc388 [ 95.890755] head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 [ 95.890755] ano —truncated—

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/012363cb1bec5f33a7b94629ab2c1086f30280f2
• https://git.kernel.org/stable/c/1b33d55fb7355e27f8c82cd4ecd560f162469249
• https://git.kernel.org/stable/c/3212afd00e3cda790fd0583cb3eaef8f9575a014
• https://git.kernel.org/stable/c/33a6e92161a78c1073d90e27abe28d746feb0a53
• https://git.kernel.org/stable/c/483bc08181827fc475643272ffb69c533007e546
• https://git.kernel.org/stable/c/50c2037fc28df870ef29d9728c770c8955d32178
• https://git.kernel.org/stable/c/6a18eeb1b3bbc67c20d9609c31dca6a69b4bcde5
• https://git.kernel.org/stable/c/bfab2c1f7940a232cd519e82fff137e308abfd93
• http://www.openwall.com/lists/oss-security/2024/11/29/1
• http://www.openwall.com/lists/oss-security/2024/11/30/1
• http://www.openwall.com/lists/oss-security/2024/11/30/2
• https://git.kernel.org/stable/c/012363cb1bec5f33a7b94629ab2c1086f30280f2
• https://git.kernel.org/stable/c/1b33d55fb7355e27f8c82cd4ecd560f162469249
• https://git.kernel.org/stable/c/3212afd00e3cda790fd0583cb3eaef8f9575a014
• https://git.kernel.org/stable/c/33a6e92161a78c1073d90e27abe28d746feb0a53
• https://git.kernel.org/stable/c/483bc08181827fc475643272ffb69c533007e546
• https://git.kernel.org/stable/c/50c2037fc28df870ef29d9728c770c8955d32178
• https://git.kernel.org/stable/c/6a18eeb1b3bbc67c20d9609c31dca6a69b4bcde5
• https://git.kernel.org/stable/c/bfab2c1f7940a232cd519e82fff137e308abfd93
• https://lists.debian.org/debian-lts-announce/2024/06/msg00019.html
• https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DW2MIOIMOFUSNLHLRYX23AFR36BMKD65/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OTB4HWU2PTVW5NEYHHLOCXDKG3PYA534/
• https://security.netapp.com/advisory/ntap-20240912-0012/