Ubuntu: (Multiple Advisories) (CVE-2024-40955): Linux kernel vulnerabilities
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists() We can trigger a slab-out-of-bounds with the following commands: mkfs.ext4 -F /dev/$disk 10G mount /dev/$disk /tmp/test echo 2147483647 > /sys/fs/ext4/$disk/mb_group_prealloc echo test > /tmp/test/file && sync ================================================================== BUG: KASAN: slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4] Read of size 8 at addr ffff888121b9d0f0 by task kworker/u2:0/11 CPU: 0 PID: 11 Comm: kworker/u2:0 Tainted: GL 6.7.0-next-20240118 #521 Call Trace: dump_stack_lvl+0x2c/0x50 kasan_report+0xb6/0xf0 ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4] ext4_mb_regular_allocator+0x19e9/0x2370 [ext4] ext4_mb_new_blocks+0x88a/0x1370 [ext4] ext4_ext_map_blocks+0x14f7/0x2390 [ext4] ext4_map_blocks+0x569/0xea0 [ext4] ext4_do_writepages+0x10f6/0x1bc0 [ext4] [...] ================================================================== The flow of issue triggering is as follows: // Set s_mb_group_prealloc to 2147483647 via sysfs ext4_mb_new_blocks ext4_mb_normalize_request ext4_mb_normalize_group_request ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc ext4_mb_regular_allocator ext4_mb_choose_next_group ext4_mb_choose_next_group_best_avail mb_avg_fragment_size_order order = fls(len) - 2 = 29 ext4_mb_find_good_group_avg_frag_lists frag_list = &sbi->s_mb_avg_fragment_size[order] if (list_empty(frag_list)) // Trigger SOOB! At 4k block size, the length of the s_mb_avg_fragment_size list is 14, but an oversized s_mb_group_prealloc is set, causing slab-out-of-bounds to be triggered by an attempt to access an element at index 29. Add a new attr_id attr_clusters_in_group with values in the range [0, sbi->s_clusters_per_group] and declare mb_group_prealloc as that type to fix the issue. In addition avoid returning an order from mb_avg_fragment_size_order() greater than MB_NUM_ORDERS(sb) and reduce some useless loops.
Solution(s)
- ubuntu-upgrade-linux-image-6-8-0-1010-gke
- ubuntu-upgrade-linux-image-6-8-0-1011-raspi
- ubuntu-upgrade-linux-image-6-8-0-1012-ibm
- ubuntu-upgrade-linux-image-6-8-0-1012-oem
- ubuntu-upgrade-linux-image-6-8-0-1012-oracle
- ubuntu-upgrade-linux-image-6-8-0-1012-oracle-64k
- ubuntu-upgrade-linux-image-6-8-0-1013-nvidia
- ubuntu-upgrade-linux-image-6-8-0-1013-nvidia-64k
- ubuntu-upgrade-linux-image-6-8-0-1013-nvidia-lowlatency
- ubuntu-upgrade-linux-image-6-8-0-1013-nvidia-lowlatency-64k
- ubuntu-upgrade-linux-image-6-8-0-1014-azure
- ubuntu-upgrade-linux-image-6-8-0-1014-azure-fde
- ubuntu-upgrade-linux-image-6-8-0-1014-gcp
- ubuntu-upgrade-linux-image-6-8-0-1015-aws
- ubuntu-upgrade-linux-image-6-8-0-44-generic
- ubuntu-upgrade-linux-image-6-8-0-44-generic-64k
- ubuntu-upgrade-linux-image-6-8-0-44-lowlatency
- ubuntu-upgrade-linux-image-6-8-0-44-lowlatency-64k
- ubuntu-upgrade-linux-image-6-8-0-45-generic
- ubuntu-upgrade-linux-image-6-8-0-45-generic-64k
- ubuntu-upgrade-linux-image-aws
- ubuntu-upgrade-linux-image-azure
- ubuntu-upgrade-linux-image-azure-fde
- ubuntu-upgrade-linux-image-gcp
- ubuntu-upgrade-linux-image-generic
- ubuntu-upgrade-linux-image-generic-64k
- ubuntu-upgrade-linux-image-generic-64k-hwe-22-04
- ubuntu-upgrade-linux-image-generic-64k-hwe-24-04
- ubuntu-upgrade-linux-image-generic-hwe-22-04
- ubuntu-upgrade-linux-image-generic-hwe-24-04
- ubuntu-upgrade-linux-image-generic-lpae
- ubuntu-upgrade-linux-image-gke
- ubuntu-upgrade-linux-image-ibm
- ubuntu-upgrade-linux-image-ibm-classic
- ubuntu-upgrade-linux-image-ibm-lts-24-04
- ubuntu-upgrade-linux-image-kvm
- ubuntu-upgrade-linux-image-lowlatency
- ubuntu-upgrade-linux-image-lowlatency-64k
- ubuntu-upgrade-linux-image-lowlatency-64k-hwe-22-04
- ubuntu-upgrade-linux-image-lowlatency-hwe-22-04
- ubuntu-upgrade-linux-image-nvidia
- ubuntu-upgrade-linux-image-nvidia-6-8
- ubuntu-upgrade-linux-image-nvidia-64k
- ubuntu-upgrade-linux-image-nvidia-64k-6-8
- ubuntu-upgrade-linux-image-nvidia-lowlatency
- ubuntu-upgrade-linux-image-nvidia-lowlatency-64k
- ubuntu-upgrade-linux-image-oem-22-04
- ubuntu-upgrade-linux-image-oem-22-04a
- ubuntu-upgrade-linux-image-oem-22-04b
- ubuntu-upgrade-linux-image-oem-22-04c
- ubuntu-upgrade-linux-image-oem-22-04d
- ubuntu-upgrade-linux-image-oracle
- ubuntu-upgrade-linux-image-oracle-64k
- ubuntu-upgrade-linux-image-raspi
- ubuntu-upgrade-linux-image-virtual
- ubuntu-upgrade-linux-image-virtual-hwe-22-04
- ubuntu-upgrade-linux-image-virtual-hwe-24-04
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