Lifecycle Timeline
2DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_iter+0x2b5/0x4e0 vfs_read+0x7f4/0xae0 ksys_read+0x12a/0x250 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}: __lock_acquire+0x1509/0x26d0 lock_acquire+0x185/0x340 down_read+0x98/0x490 blkdev_read_iter+0x2a7/0x4e0 __kernel_read+0x39a/0xa90 freader_fetch+0x1d5/0xa80 __build_id_parse.isra.0+0xea/0x6a0 do_procmap_query+0xd75/0x1050 procfs_procmap_ioctl+0x7a/0xb0 __x64_sys_ioctl+0x18e/0x210 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#8); lock(&mm->mmap_lock); rlock(&sb->s_type->i_mutex_key#8);
* DEADLOCK *
This seems to be exacerbated (as we haven't seen these syzbot reports before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but other than that everything is pretty straightforward. Internal build_id_parse() API assumes VMA is passed, but it only needs the underlying file reference, so just add another variant build_id_parse_file() that expects file passed directly.
[akpm@linux-foundation.org: fix up kerneldoc]
AnalysisAI
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_iter+0x2b5/0x4e0 vfs_read+0x7f4/0xae0 ksys_read+0x12a/0x250 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}: __lock_acquire+0x1509/0x26d0 lock_acquire+0x185/0x340 down_read+0x98/0x490 blkdev_read_iter+0x2a7/0x4e0 __kernel_read+0x39a/0xa90 freader_fetch+0x1d5/0xa80 __build_id_parse.isra.0+0xea/0x6a0 do_procmap_query+0xd75/0x1050 procfs_procmap_ioctl+0x7a/0xb0 __x64_sys_ioctl+0x18e/0x210 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#8); lock(&mm->mmap_lock); rlock(&sb->s_type->i_mutex_key#8);
* DEADLOCK *
This seems to be exacerbated (as we haven't seen these syzbot reports before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but other than that everything is pretty straightforward.
Technical ContextAI
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_
Affected ProductsAI
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetc
RemediationAI
Monitor vendor advisories for a patch.
More in Linux Kernel
View allLinux kernel contains a flaw known as 'Dirty Pipe' where improper pipe buffer flag initialization allows unprivileged lo
The overlayfs implementation in the linux (aka Linux kernel) package before 3.19.0-21.21 in Ubuntu through 15.04 does no
The packet_set_ring function in net/packet/af_packet.c in the Linux kernel through 4.10.6 does not properly validate cer
The check_alu_op function in kernel/bpf/verifier.c in the Linux kernel through 4.4 allows local users to cause a denial
Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. Rated high severity (CVSS 7.0). Public ex
The ovl_setattr function in fs/overlayfs/inode.c in the Linux kernel through 4.3.3 attempts to merge distinct setattr op
The mem_write function in the Linux kernel before 3.2.2, when ASLR is disabled, does not properly check permissions when
The compat_sys_recvmmsg function in net/compat.c in the Linux kernel before 3.13.2, when CONFIG_X86_X32 is enabled, allo
Race condition in net/packet/af_packet.c in the Linux kernel through 4.8.12 allows local users to gain privileges or cau
The join_session_keyring function in security/keys/process_keys.c in the Linux kernel before 4.4.1 mishandles object ref
A remote code execution vulnerability in the Broadcom Wi-Fi firmware could enable a remote attacker to execute arbitrary
It was discovered that the cls_route filter implementation in the Linux kernel would not remove an old filter from the h
Share
External POC / Exploit Code
Leaving vuln.today