2.0 KiB
CVE-2021-47117
Description
In the Linux kernel, the following vulnerability has been resolved:ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failedWe got follow bug_on when run fsstress with injecting IO fault:[130747.323114] kernel BUG at fs/ext4/extents_status.c:762![130747.323117] Internal error: Oops - BUG: 0 [#1] SMP......[130747.334329] Call trace:[130747.334553] ext4_es_cache_extent+0x150/0x168 [ext4][130747.334975] ext4_cache_extents+0x64/0xe8 [ext4][130747.335368] ext4_find_extent+0x300/0x330 [ext4][130747.335759] ext4_ext_map_blocks+0x74/0x1178 [ext4][130747.336179] ext4_map_blocks+0x2f4/0x5f0 [ext4][130747.336567] ext4_mpage_readpages+0x4a8/0x7a8 [ext4][130747.336995] ext4_readpage+0x54/0x100 [ext4][130747.337359] generic_file_buffered_read+0x410/0xae8[130747.337767] generic_file_read_iter+0x114/0x190[130747.338152] ext4_file_read_iter+0x5c/0x140 [ext4][130747.338556] __vfs_read+0x11c/0x188[130747.338851] vfs_read+0x94/0x150[130747.339110] ksys_read+0x74/0xf0This patch's modification is according to Jan Kara's suggestion in:https://patchwork.ozlabs.org/project/linux-ext4/patch/20210428085158.3728201-1-yebin10@huawei.com/"I see. Now I understand your patch. Honestly, seeing how fragile is tryingto fix extent tree after split has failed in the middle, I would probablygo even further and make sure we fix the tree properly in case of ENOSPCand EDQUOT (those are easily user triggerable). Anything else indicates aHW problem or fs corruption so I'd rather leave the extent tree as is anddon't try to fix it (which also means we will not create overlappingextents)."
POC
Reference
No PoCs from references.