Agreed, SBI_NEED_FSCK may not be persisted at this stage. I sent v2 to add ERROR_INCONSISTENT_ORPHAN and call f2fs_handle_error() on invalid orphan entry_count, so the corruption reason can be recorded in s_errors[] as a persistent hint for fsck.
https://lore.kernel.org/linux-f2fs-devel/[email protected]/T/#u On Tue, May 26, 2026 at 10:19 AM Chao Yu <[email protected]> wrote: > > On 5/25/26 19:46, Wenjie Qi wrote: > > f2fs_recover_orphan_inodes() trusts the orphan block entry_count when > > replaying orphan inodes from the checkpoint pack. A corrupted > > entry_count larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop > > read past the ino[] array and interpret footer or following data as > > inode numbers. > > > > On a crafted image, mounting an unpatched kernel can drive orphan > > recovery into f2fs_bug_on() and panic the kernel. Validate entry_count > > before consuming entries so corrupted checkpoint data fails the mount > > with -EFSCORRUPTED and requests fsck instead. > > > > Fixes: 127e670abfa7 ("f2fs: add checkpoint operations") > > Cc: [email protected] > > Signed-off-by: Wenjie Qi <[email protected]> > > --- > > fs/f2fs/checkpoint.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > > index c00a6b6ebcbd..fc72b69ff769 100644 > > --- a/fs/f2fs/checkpoint.c > > +++ b/fs/f2fs/checkpoint.c > > @@ -943,6 +943,7 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi) > > for (i = 0; i < orphan_blocks; i++) { > > struct folio *folio; > > struct f2fs_orphan_block *orphan_blk; > > + unsigned int entry_count; > > > > folio = f2fs_get_meta_folio(sbi, start_blk + i); > > if (IS_ERR(folio)) { > > @@ -951,7 +952,17 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info > > *sbi) > > } > > > > orphan_blk = folio_address(folio); > > - for (j = 0; j < le32_to_cpu(orphan_blk->entry_count); j++) { > > + entry_count = le32_to_cpu(orphan_blk->entry_count); > > + if (entry_count > F2FS_ORPHANS_PER_BLOCK) { > > + f2fs_err(sbi, "invalid orphan inode entry count %u", > > + entry_count); > > + set_sbi_flag(sbi, SBI_NEED_FSCK); > > Well, at this stage, I guess there is no chance to persist SBI_NEED_FSCK flag, > what about introduce ERROR_INCONSISTENT_ORPHAN in enum f2fs_error, so that > we can persist the new bit to provide hint to fsck? > > Thanks, > > > + err = -EFSCORRUPTED; > > + f2fs_folio_put(folio, true); > > + goto out; > > + } > > + > > + for (j = 0; j < entry_count; j++) { > > nid_t ino = le32_to_cpu(orphan_blk->ino[j]); > > > > err = recover_orphan_inode(sbi, ino); > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
