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| author | Baokun Li <libaokun1@huawei.com> | 2022-10-26 06:23:09 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2022-12-09 03:49:23 +0100 |
| commit | 63b1e9bccb71fe7d7e3ddc9877dbdc85e5d2d023 (patch) | |
| tree | 4ed38e687a8091cd17a1a9499802083fb2157dab /fs/ext4 | |
| parent | ext4: add helper to check quota inums (diff) | |
| download | linux-63b1e9bccb71fe7d7e3ddc9877dbdc85e5d2d023.tar.xz linux-63b1e9bccb71fe7d7e3ddc9877dbdc85e5d2d023.zip | |
ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode
There are many places that will get unhappy (and crash) when ext4_iget()
returns a bad inode. However, if iget the boot loader inode, allows a bad
inode to be returned, because the inode may not be initialized. This
mechanism can be used to bypass some checks and cause panic. To solve this
problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag
we'd be returning bad inode from ext4_iget(), otherwise we always return
the error code if the inode is bad inode.(suggested by Jan Kara)
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221026042310.3839669-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4.h | 3 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 8 | ||||
| -rw-r--r-- | fs/ext4/ioctl.c | 3 |
3 files changed, 11 insertions, 3 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 8d5453852f98..2b574b143bde 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2964,7 +2964,8 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode, typedef enum { EXT4_IGET_NORMAL = 0, EXT4_IGET_SPECIAL = 0x0001, /* OK to iget a system inode */ - EXT4_IGET_HANDLE = 0x0002 /* Inode # is from a handle */ + EXT4_IGET_HANDLE = 0x0002, /* Inode # is from a handle */ + EXT4_IGET_BAD = 0x0004 /* Allow to iget a bad inode */ } ext4_iget_flags; extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 6d16241666e6..a4bf643aa08b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5058,8 +5058,14 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) ext4_error_inode(inode, function, line, 0, "casefold flag without casefold feature"); - brelse(iloc.bh); + if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD)) { + ext4_error_inode(inode, function, line, 0, + "bad inode without EXT4_IGET_BAD flag"); + ret = -EUCLEAN; + goto bad_inode; + } + brelse(iloc.bh); unlock_new_inode(inode); return inode; diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 95dfea28bf4e..9ed7b9fe2132 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -374,7 +374,8 @@ static long swap_inode_boot_loader(struct super_block *sb, blkcnt_t blocks; unsigned short bytes; - inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL); + inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO, + EXT4_IGET_SPECIAL | EXT4_IGET_BAD); if (IS_ERR(inode_bl)) return PTR_ERR(inode_bl); ei_bl = EXT4_I(inode_bl); |