CVE-2022-48903: Vulnerability in Linux Linux

Severity: highType: vulnerabilityCVE-2022-48903

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix relocation crash due to premature return from btrfs_commit_transaction() We are seeing crashes similar to the following trace: [38.969182] WARNING: CPU: 20 PID: 2105 at fs/btrfs/relocation.c:4070 btrfs_relocate_block_group+0x2dc/0x340 [btrfs] [38.973556] CPU: 20 PID: 2105 Comm: btrfs Not tainted 5.17.0-rc4 #54 [38.974580] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [38.976539] RIP: 0010:btrfs_relocate_block_group+0x2dc/0x340 [btrfs] [38.980336] RSP: 0000:ffffb0dd42e03c20 EFLAGS: 00010206 [38.981218] RAX: ffff96cfc4ede800 RBX: ffff96cfc3ce0000 RCX: 000000000002ca14 [38.982560] RDX: 0000000000000000 RSI: 4cfd109a0bcb5d7f RDI: ffff96cfc3ce0360 [38.983619] RBP: ffff96cfc309c000 R08: 0000000000000000 R09: 0000000000000000 [38.984678] R10: ffff96cec0000001 R11: ffffe84c80000000 R12: ffff96cfc4ede800 [38.985735] R13: 0000000000000000 R14: 0000000000000000 R15: ffff96cfc3ce0360 [38.987146] FS: 00007f11c15218c0(0000) GS:ffff96d6dfb00000(0000) knlGS:0000000000000000 [38.988662] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [38.989398] CR2: 00007ffc922c8e60 CR3: 00000001147a6001 CR4: 0000000000370ee0 [38.990279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [38.991219] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [38.992528] Call Trace: [38.992854] <TASK> [38.993148] btrfs_relocate_chunk+0x27/0xe0 [btrfs] [38.993941] btrfs_balance+0x78e/0xea0 [btrfs] [38.994801] ? vsnprintf+0x33c/0x520 [38.995368] ? __kmalloc_track_caller+0x351/0x440 [38.996198] btrfs_ioctl_balance+0x2b9/0x3a0 [btrfs] [38.997084] btrfs_ioctl+0x11b0/0x2da0 [btrfs] [38.997867] ? mod_objcg_state+0xee/0x340 [38.998552] ? seq_release+0x24/0x30 [38.999184] ? proc_nr_files+0x30/0x30 [38.999654] ? call_rcu+0xc8/0x2f0 [39.000228] ? __x64_sys_ioctl+0x84/0xc0 [39.000872] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [39.001973] __x64_sys_ioctl+0x84/0xc0 [39.002566] do_syscall_64+0x3a/0x80 [39.003011] entry_SYSCALL_64_after_hwframe+0x44/0xae [39.003735] RIP: 0033:0x7f11c166959b [39.007324] RSP: 002b:00007fff2543e998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [39.008521] RAX: ffffffffffffffda RBX: 00007f11c1521698 RCX: 00007f11c166959b [39.009833] RDX: 00007fff2543ea40 RSI: 00000000c4009420 RDI: 0000000000000003 [39.011270] RBP: 0000000000000003 R08: 0000000000000013 R09: 00007f11c16f94e0 [39.012581] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff25440df3 [39.014046] R13: 0000000000000000 R14: 00007fff2543ea40 R15: 0000000000000001 [39.015040] </TASK> [39.015418] ---[ end trace 0000000000000000 ]--- [43.131559] ------------[ cut here ]------------ [43.132234] kernel BUG at fs/btrfs/extent-tree.c:2717! [43.133031] invalid opcode: 0000 [#1] PREEMPT SMP PTI [43.133702] CPU: 1 PID: 1839 Comm: btrfs Tainted: G W 5.17.0-rc4 #54 [43.134863] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [43.136426] RIP: 0010:unpin_extent_range+0x37a/0x4f0 [btrfs] [43.139913] RSP: 0000:ffffb0dd4216bc70 EFLAGS: 00010246 [43.140629] RAX: 0000000000000000 RBX: ffff96cfc34490f8 RCX: 0000000000000001 [43.141604] RDX: 0000000080000001 RSI: 0000000051d00000 RDI: 00000000ffffffff [43.142645] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff96cfd07dca50 [43.143669] R10: ffff96cfc46e8a00 R11: fffffffffffec000 R12: 0000000041d00000 [43.144657] R13: ffff96cfc3ce0000 R14: ffffb0dd4216bd08 R15: 0000000000000000 [43.145686] FS: 00007f7657dd68c0(0000) GS:ffff96d6df640000(0000) knlGS:0000000000000000 [43.146808] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [43.147584] CR2: 00007f7fe81bf5b0 CR3: 00000001093ee004 CR4: 0000000000370ee0 [43.148589] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [43.149581] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 00000000000 ---truncated---

AI Analysis

Technical Summary

CVE-2022-48903 is a vulnerability in the Linux kernel's Btrfs filesystem implementation, specifically related to the relocation process during transaction commits. The issue arises from a premature return in the function btrfs_commit_transaction(), which leads to a crash during block group relocation operations. The vulnerability manifests as kernel crashes and kernel bugs, as evidenced by the provided kernel stack traces showing faults in btrfs_relocate_block_group and unpin_extent_range functions. These crashes occur due to improper handling of relocation transactions, causing invalid memory operations and kernel panics. The vulnerability affects Linux kernel versions that include the affected commit hashes referenced, and it is related to the Btrfs filesystem's balance and relocation ioctl operations. While no known exploits are currently reported in the wild, the nature of the bug—causing kernel crashes—could be leveraged for denial-of-service attacks or potentially escalated to privilege escalation if combined with other vulnerabilities. The vulnerability does not require user interaction but does require access to the Btrfs filesystem and the ability to invoke ioctl operations that trigger relocation or balance commands. This vulnerability has been publicly disclosed and patched, but no CVSS score has been assigned yet.

Potential Impact

For European organizations, the impact of CVE-2022-48903 primarily concerns systems running Linux with Btrfs filesystems, which are used in various enterprise and cloud environments. The vulnerability can cause system instability, crashes, and potential denial-of-service conditions, impacting availability of critical services. Organizations relying on Btrfs for storage, especially those using it in production environments for databases, virtual machines, or container storage, may experience outages or data access interruptions. Although no direct evidence of privilege escalation exists, the kernel panic could be exploited in multi-tenant environments or cloud infrastructures to disrupt services or force reboots, affecting business continuity. Given the widespread use of Linux in European data centers, cloud providers, and enterprises, the vulnerability poses a moderate risk to availability and operational stability. Confidentiality and integrity impacts are less direct but could arise if attackers combine this vulnerability with others to gain elevated privileges or cause data corruption during filesystem operations.

Mitigation Recommendations

European organizations should immediately verify if their Linux kernel versions include the affected Btrfs code and apply the official patches or kernel updates that address CVE-2022-48903. Specifically, updating to the latest stable Linux kernel releases that incorporate the fix for the premature return in btrfs_commit_transaction() is critical. For systems where immediate patching is not feasible, administrators should restrict access to Btrfs ioctl operations by limiting permissions to trusted users and processes only. Monitoring kernel logs for signs of btrfs_relocate_block_group or related crashes can provide early detection of exploitation attempts or instability. Additionally, organizations should consider implementing filesystem-level backups and snapshots to mitigate potential data loss from crashes. In virtualized or containerized environments, isolating workloads using Btrfs and limiting exposure to untrusted users can reduce risk. Finally, coordinating with Linux distribution vendors for timely updates and testing patches in staging environments before production deployment will ensure stability and security.