cbcvebase.
CVE-2024-35956
published 2024-05-20

CVE-2024-35956: In the Linux kernel, the following vulnerability has been resolved: btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations Create subvolume…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.23%
13.7th percentile
In the Linux kernel, the following vulnerability has been resolved: btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations Create subvolume, create snapshot and delete subvolume all use btrfs_subvolume_reserve_metadata() to reserve metadata for the changes done to the parent subvolume's fs tree, which cannot be mediated in the normal way via start_transaction. When quota groups (squota or qgroups) are enabled, this reserves qgroup metadata of type PREALLOC. Once the operation is associated to a transaction, we convert PREALLOC to PERTRANS, which gets cleared in bulk at the end of the transaction. However, the error paths of these three operations were not implementing this lifecycle correctly. They unconditionally converted the PREALLOC to PERTRANS in a generic cleanup step regardless of errors or whether the operation was fully associated to a transaction or not. This resulted in error paths occasionally converting this rsv to PERTRANS without calling record_root_in_trans successfully, which meant that unless that root got recorded in the transaction by some other thread, the end of the transaction would not free that root's PERTRANS, leaking it. Ultimately, this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount for the leaked reservation. The fix is to ensure that every qgroup PREALLOC reservation observes the following properties: 1. any failure before record_root_in_trans is called successfully results in freeing the PREALLOC reservation. 2. after record_root_in_trans, we convert to PERTRANS, and now the transaction owns freeing the reservation. This patch enforces those properties on the three operations. Without it, generic/269 with squotas enabled at mkfs time would fail in ~5-10 runs on my system. With this patch, it ran successfully 1000 times in a row.

Affected

20 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
debianlinux-6.1< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
linuxlinux
linuxlinux
linuxlinux>= 5.9.5 < 5.105.10
linuxlinux>= e85fde5162bf1b242cbd6daf7dba0f9b457d592b < 945559be6e282a812dc48f7bcd5adc60901ea4a0945559be6e282a812dc48f7bcd5adc60901ea4a0
linuxlinux>= e85fde5162bf1b242cbd6daf7dba0f9b457d592b < 14431815a4ae4bcd7c7a68b6a64c66c7712d27c914431815a4ae4bcd7c7a68b6a64c66c7712d27c9
linuxlinux>= e85fde5162bf1b242cbd6daf7dba0f9b457d592b < 6c95336f5d8eb9ab79cd7306d71b6d0477363f8c6c95336f5d8eb9ab79cd7306d71b6d0477363f8c
linuxlinux>= e85fde5162bf1b242cbd6daf7dba0f9b457d592b < 74e97958121aa1f5854da6effba70143f051b0cd74e97958121aa1f5854da6effba70143f051b0cd
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.1.123-16.1.123-1
linuxlinux_kernel>= 0 < 6.8.9-16.8.9-1
linuxlinux_kernel>= 0 < 6.8.9-16.8.9-1
linuxlinux_kernel>= 0 < 6.8.0-38.386.8.0-38.38
linuxlinux_kernel>= 5.9.5 < 6.1.1206.1.120
linuxlinux_kernel>= 6.2 < 6.6.286.6.28
linuxlinux_kernel>= 6.7 < 6.8.76.8.7
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv6.8MEDIUM
vendor_debian5.5MEDIUM
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
vendor_ubuntu4.6MEDIUM
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