In the Linux kernel, the following vulnerability has been resolved:

ext4: turn quotas off if mount failed after enabling quotas

Yi found during a review of the patch ext4: dont BUG on inconsistent journal feature that when ext4_mark_recovery_complete() returns an error value, the error handling path does not turn off the enabled quotas, which triggers the following kmemleak:

================================================================ unreferenced object 0xffff8cf68678e7c0 (size 64): comm mount, pid 746, jiffies 4294871231 (age 11.540s) hex dump (first 32 bytes): 00 90 ef 82 f6 8c ff ff 00 00 00 00 41 01 00 00 …………A… c7 00 00 00 bd 00 00 00 0a 00 00 00 48 00 00 00 …………H… backtrace: [<00000000c561ef24>] __kmem_cache_alloc_node+0x4d4/0x880 [<00000000d4e621d7>] kmalloc_trace+0x39/0x140 [<00000000837eee74>] v2_read_file_info+0x18a/0x3a0 [<0000000088f6c877>] dquot_load_quota_sb+0x2ed/0x770 [<00000000340a4782>] dquot_load_quota_inode+0xc6/0x1c0 [<0000000089a18bd5>] ext4_enable_quotas+0x17e/0x3a0 [ext4] [<000000003a0268fa>] __ext4_fill_super+0x3448/0x3910 [ext4] [<00000000b0f2a8a8>] ext4_fill_super+0x13d/0x340 [ext4] [<000000004a9489c4>] get_tree_bdev+0x1dc/0x370 [<000000006e723bf1>] ext4_get_tree+0x1d/0x30 [ext4] [<00000000c7cb663d>] vfs_get_tree+0x31/0x160 [<00000000320e1bed>] do_new_mount+0x1d5/0x480 [<00000000c074654c>] path_mount+0x22e/0xbe0 [<0000000003e97a8e>] do_mount+0x95/0xc0 [<000000002f3d3736>] __x64_sys_mount+0xc4/0x160 [<0000000027d2140c>] do_syscall_64+0x3f/0x90

To solve this problem, we add a failed_mount10 tag, and call ext4_quota_off_umount() in this tag to release the enabled qoutas.

Affected Software

References

• https://git.kernel.org/stable/c/77c3ca1108eb4a26db4f256c42b271a430cebc7d
• https://git.kernel.org/stable/c/c327b83c59ee938792a0300df646efac39c7d6a7
• https://git.kernel.org/stable/c/d13f99632748462c32fc95d729f5e754bab06064
• https://git.kernel.org/stable/c/deef86fa3005cbb61ae8aa5729324c09b3f4ba73