On 2025/07/25 4:49, Viacheslav Dubeyko wrote: > On Thu, 2025-07-24 at 15:55 +0900, Tetsuo Handa wrote: >> Then, something like below change? >> >> --- a/fs/hfs/inode.c >> +++ b/fs/hfs/inode.c >> @@ -318,6 +318,9 @@ static int hfs_read_inode(struct inode *inode, void *data) >> struct hfs_iget_data *idata = data; >> struct hfs_sb_info *hsb = HFS_SB(inode->i_sb); >> hfs_cat_rec *rec; >> + /* https://developer.apple.com/library/archive/technotes/tn/tn1150.html#CNID */ > > We already have all declarations in hfs.h: > > /* Some special File ID numbers */ > #define HFS_POR_CNID 1 /* Parent Of the Root */ > #define HFS_ROOT_CNID 2 /* ROOT directory */ > #define HFS_EXT_CNID 3 /* EXTents B-tree */ > #define HFS_CAT_CNID 4 /* CATalog B-tree */ > #define HFS_BAD_CNID 5 /* BAD blocks file */ > #define HFS_ALLOC_CNID 6 /* ALLOCation file (HFS+) */ > #define HFS_START_CNID 7 /* STARTup file (HFS+) */ > #define HFS_ATTR_CNID 8 /* ATTRibutes file (HFS+) */ > #define HFS_EXCH_CNID 15 /* ExchangeFiles temp id */ > #define HFS_FIRSTUSER_CNID 16 These declarations does not define 14, and some flags are never used despite being declared here. > > So, adding the link here doesn't make any sense. > >> + static const u16 bad_cnid_list = (1 << 0) | (1 << 6) | (1 << 7) | (1 << 8) | >> + (1 << 9) | (1 << 10) | (1 << 11) | (1 << 12) | (1 << 13); Some of values in this constant are not declared. > > I don't see any sense to introduce flags here. First of all, please, don't use > hardcoded values but you should use declared constants from hfs.h (for example, > HFS_EXT_CNID instead of 3). Secondly, you can simply compare the i_ino with > constants, for example: This will save a lot of computational power compared to switch(). > > bool is_inode_id_invalid(u64 ino) { > switch (inode->i_ino) { > case HFS_EXT_CNID: > ... > return true; > > } > > return false; > } > > Thirdly, you can introduce an inline function that can do such check. And it > make sense to introduce constant for the case of zero value. > > Why have you missed HFS_EXT_CNID, HFS_CAT_CNID? These values cannot used in > hfs_read_inode(). Is hfs_read_inode() never called for HFS_EXT_CNID and HFS_CAT_CNID ? > >> >> HFS_I(inode)->flags = 0; >> HFS_I(inode)->rsrc_inode = NULL; >> @@ -358,6 +361,8 @@ static int hfs_read_inode(struct inode *inode, void *data) >> inode->i_op = &hfs_file_inode_operations; >> inode->i_fop = &hfs_file_operations; >> inode->i_mapping->a_ops = &hfs_aops; >> + if (inode->i_ino < HFS_FIRSTUSER_CNID && ((1U << inode->i_ino) & bad_cnid_list)) >> + make_bad_inode(inode); > > It looks pretty complicated. You can simply use one above-mentioned function > with the check: > > if (is_inode_id_invalid(be32_to_cpu(rec->dir.DirID))) > <goto to make bad inode> > > We can simply check the the inode ID in the beginning of the whole action: > > <Make the check here> > inode->i_ino = be32_to_cpu(rec->file.FlNum); > inode->i_mode = S_IRUGO | S_IXUGO; > if (!(rec->file.Flags & HFS_FIL_LOCK)) > inode->i_mode |= S_IWUGO; > inode->i_mode &= ~hsb->s_file_umask; > inode->i_mode |= S_IFREG; > inode_set_mtime_to_ts(inode, > inode_set_atime_to_ts(inode, > inode_set_ctime_to_ts(inode, hfs_m_to_utime(rec->file.MdDat)))); > inode->i_op = &hfs_file_inode_operations; > inode->i_fop = &hfs_file_operations; > inode->i_mapping->a_ops = &hfs_aops; > > It doesn't make any sense to construct inode if we will make in bad inode, > finally. Don't waste computational power. :) > >> break; >> case HFS_CDR_DIR: >> inode->i_ino = be32_to_cpu(rec->dir.DirID); >> @@ -368,6 +373,8 @@ static int hfs_read_inode(struct inode *inode, void *data) >> inode_set_atime_to_ts(inode, inode_set_ctime_to_ts(inode, hfs_m_to_utime(rec->dir.MdDat)))); >> inode->i_op = &hfs_dir_inode_operations; >> inode->i_fop = &hfs_dir_operations; >> + if (inode->i_ino < HFS_FIRSTUSER_CNID && ((1U << inode->i_ino) & bad_cnid_list)) >> + make_bad_inode(inode); > > We already have make_bad_inode(inode) as default action. So, simply jump there. > >> break; >> default: >> make_bad_inode(inode); >> >> >> >> But I can't be convinced that above change is sufficient, for if I do >> >> + static u8 serial; >> + if (inode->i_ino < HFS_FIRSTUSER_CNID && ((1U << inode->i_ino) & bad_cnid_list)) >> + inode->i_ino = (serial++) % 16; > > I don't see the point in flags introduction. It makes logic very complicated. The point of this change is to excecise inode->i_ino for all values between 0 and 15. Some of values between 0 and 15 must be valid as inode->i_ino , doesn't these? Then, > >> >> instead of >> >> + if (inode->i_ino < HFS_FIRSTUSER_CNID && ((1U << inode->i_ino) & bad_cnid_list)) >> + make_bad_inode(inode); >> >> , the reproducer still hits BUG() for 0, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15 >> because hfs_write_inode() handles only 2, 3 and 4. >> > > How can we go into hfs_write_inode() if we created the bad inode for invalid > inode ID? How is it possible? are all of 0, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15 invalid value for hfs_read_inode() ? If all of 0, 1, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15 are invalid value for hfs_read_inode(), and 3 and 4 are also invalid value for hfs_read_inode(), hfs_read_inode() would accept only 2. Something is crazily wrong. Can we really filter some of values between 0 and 15 at hfs_read_inode() ?
