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Vulnerability · Published Apr 28, 2024 · Assigned by Linux

CVE-2022-48631ext4: fix bug in extents parsing when eh_entries == 0 and eh_depth > 0

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 85.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix bug in extents parsing when eh_entries == 0 and eh_depth > 0 When walking through an inode extents, the ext4_ext_binsearch_idx() function assumes that the extent header has been previously validated. However, there are no checks that verify that the number of entries (eh->eh_entries) is non-zero when depth is > 0. And this will lead to problems because the EXT_FIRST_INDEX() and EXT_LAST_INDEX() will return garbage and result in this: [ 135.245946] ------------[ cut here ]------------ [ 135.247579] kernel BUG at fs/ext4/extents.c:2258! [ 135.249045] invalid opcode: 0000 [#1] PREEMPT SMP [ 135.250320] CPU: 2 PID: 238 Comm: tmp118 Not tainted 5.19.0-rc8+ #4 [ 135.252067] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 [ 135.255065] RIP: 0010:ext4_ext_map_blocks+0xc20/0xcb0 [ 135.256475] Code: [ 135.261433] RSP: 0018:ffffc900005939f8 EFLAGS: 00010246 [ 135.262847] RAX: 0000000000000024 RBX: ffffc90000593b70 RCX: 0000000000000023 [ 135.264765] RDX: ffff8880038e5f10 RSI: 0000000000000003 RDI: ffff8880046e922c [ 135.266670] RBP: ffff8880046e9348 R08: 0000000000000001 R09: ffff888002ca580c [ 135.268576] R10: 0000000000002602 R11: 0000000000000000 R12: 0000000000000024 [ 135.270477] R13: 0000000000000000 R14: 0000000000000024 R15: 0000000000000000 [ 135.272394] FS: 00007fdabdc56740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 [ 135.274510] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 135.276075] CR2: 00007ffc26bd4f00 CR3: 0000000006261004 CR4: 0000000000170ea0 [ 135.277952] Call Trace: [ 135.278635] <TASK> [ 135.279247] ? preempt_count_add+0x6d/0xa0 [ 135.280358] ? percpu_counter_add_batch+0x55/0xb0 [ 135.281612] ? _raw_read_unlock+0x18/0x30 [ 135.282704] ext4_map_blocks+0x294/0x5a0 [ 135.283745] ? xa_load+0x6f/0xa0 [ 135.284562] ext4_mpage_readpages+0x3d6/0x770 [ 135.285646] read_pages+0x67/0x1d0 [ 135.286492] ? folio_add_lru+0x51/0x80 [ 135.287441] page_cache_ra_unbounded+0x124/0x170 [ 135.288510] filemap_get_pages+0x23d/0x5a0 [ 135.289457] ? path_openat+0xa72/0xdd0 [ 135.290332] filemap_read+0xbf/0x300 [ 135.291158] ? _raw_spin_lock_irqsave+0x17/0x40 [ 135.292192] new_sync_read+0x103/0x170 [ 135.293014] vfs_read+0x15d/0x180 [ 135.293745] ksys_read+0xa1/0xe0 [ 135.294461] do_syscall_64+0x3c/0x80 [ 135.295284] entry_SYSCALL_64_after_hwframe+0x46/0xb0 This patch simply adds an extra check in __ext4_ext_check(), verifying that eh_entries is not 0 when eh_depth is > 0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.0.2-1DEBIAN-CVE-2022-48631
Debian:13linux6.0.2-1DEBIAN-CVE-2022-48631
Debian:14linux6.0.2-1DEBIAN-CVE-2022-48631
Ubuntu:22.04:LTSlinux5.15.0-57.63UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-aws5.15.0-1027.31UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure5.15.0-1030.37UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1030.37.1UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-gcp5.15.0-1026.33UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-gke5.15.0-1024.29UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1012.16UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-ibm5.15.0-1022.25UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1023.28UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-kvm5.15.0-1025.30UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-57.63UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1015.15UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-oracle5.15.0-1026.32UBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-raspi5.15.0-1022.24UBUNTU-CVE-2022-48631
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2022-48631
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2022-48631

Affected products (as reported)

VendorProductVersions
Linux Linux c29c0ae7f282828da3695167ed870131798348d9 – before bb7eb3ca4b3b0d2c7872cf1a41c30f5e5bd65df0c29c0ae7f282828da3695167ed870131798348d9 – before 958b0ee23f5ac106e7cc11472b71aa2ea9a033bcc29c0ae7f282828da3695167ed870131798348d9 – before be4df018c0be5ebecf1ca510feacc23be415cefcc29c0ae7f282828da3695167ed870131798348d9 – before 2f5e9de15e4f55fbf56f22d4a2ce406246cc462dc29c0ae7f282828da3695167ed870131798348d9 – before 29a5b8a137ac8eb410cc823653a29ac0e7b7e1b0
Linux Linux 2.6.23

References