CVE-2023-53537

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> f2fs: fix to avoid use-after-free for cached IPU bio<br /> <br /> xfstest generic/019 reports a bug:<br /> <br /> kernel BUG at mm/filemap.c:1619!<br /> RIP: 0010:folio_end_writeback+0x8a/0x90<br /> Call Trace:<br /> end_page_writeback+0x1c/0x60<br /> f2fs_write_end_io+0x199/0x420<br /> bio_endio+0x104/0x180<br /> submit_bio_noacct+0xa5/0x510<br /> submit_bio+0x48/0x80<br /> f2fs_submit_write_bio+0x35/0x300<br /> f2fs_submit_merged_ipu_write+0x2a0/0x2b0<br /> f2fs_write_single_data_page+0x838/0x8b0<br /> f2fs_write_cache_pages+0x379/0xa30<br /> f2fs_write_data_pages+0x30c/0x340<br /> do_writepages+0xd8/0x1b0<br /> __writeback_single_inode+0x44/0x370<br /> writeback_sb_inodes+0x233/0x4d0<br /> __writeback_inodes_wb+0x56/0xf0<br /> wb_writeback+0x1dd/0x2d0<br /> wb_workfn+0x367/0x4a0<br /> process_one_work+0x21d/0x430<br /> worker_thread+0x4e/0x3c0<br /> kthread+0x103/0x130<br /> ret_from_fork+0x2c/0x50<br /> <br /> The root cause is: after cp_error is set, f2fs_submit_merged_ipu_write()<br /> in f2fs_write_single_data_page() tries to flush IPU bio in cache, however<br /> f2fs_submit_merged_ipu_write() missed to check validity of @bio parameter,<br /> result in submitting random cached bio which belong to other IO context,<br /> then it will cause use-after-free issue, fix it by adding additional<br /> validity check.