| Message ID | 20230107032126.4165860-2-libaokun1@huawei.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | ext4: fix possible null pointer dereference in ext4_get_group_info | expand |
On Sat 07-01-23 11:21:25, Baokun Li wrote: > In ext4_fill_super(), EXT4_ORPHAN_FS flag is cleared after > ext4_orphan_cleanup() is executed. Therefore, when __ext4_iget() is > called to get an inode whose i_nlink is 0 when the flag exists, no error > is returned. If the inode is a special inode, a null pointer dereference > may occur. If the value of i_nlink is 0 for any inodes (except boot loader > inodes) got by using the EXT4_IGET_SPECIAL flag, the current file system > is corrupted. Therefore, make the ext4_iget() function return an error if > it gets such an abnormal special inode. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=199179 > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216541 > Link: https://bugzilla.kernel.org/show_bug.cgi?id=216539 > Reported-by: Luís Henriques <lhenriques@suse.de> > Suggested-by: Theodore Ts'o <tytso@mit.edu> > Signed-off-by: Baokun Li <libaokun1@huawei.com> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > V1->V2: > -EFSCORRUPTED is returned instead of -ESTALE for special inode > errors, and the extra parentheses are removed. > > fs/ext4/inode.c | 18 ++++++++---------- > 1 file changed, 8 insertions(+), 10 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 9d9f414f99fe..ed7598127e7c 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -4872,13 +4872,6 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, > goto bad_inode; > raw_inode = ext4_raw_inode(&iloc); > > - if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) { > - ext4_error_inode(inode, function, line, 0, > - "iget: root inode unallocated"); > - ret = -EFSCORRUPTED; > - goto bad_inode; > - } > - > if ((flags & EXT4_IGET_HANDLE) && > (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) { > ret = -ESTALE; > @@ -4951,11 +4944,16 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, > * NeilBrown 1999oct15 > */ > if (inode->i_nlink == 0) { > - if ((inode->i_mode == 0 || > + if ((inode->i_mode == 0 || flags & EXT4_IGET_SPECIAL || > !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) && > ino != EXT4_BOOT_LOADER_INO) { > - /* this inode is deleted */ > - ret = -ESTALE; > + /* this inode is deleted or unallocated */ > + if (flags & EXT4_IGET_SPECIAL) { > + ext4_error_inode(inode, function, line, 0, > + "iget: special inode unallocated"); > + ret = -EFSCORRUPTED; > + } else > + ret = -ESTALE; > goto bad_inode; > } > /* The only unlinked inodes we let through here have > -- > 2.31.1 >
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9d9f414f99fe..ed7598127e7c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4872,13 +4872,6 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, goto bad_inode; raw_inode = ext4_raw_inode(&iloc); - if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) { - ext4_error_inode(inode, function, line, 0, - "iget: root inode unallocated"); - ret = -EFSCORRUPTED; - goto bad_inode; - } - if ((flags & EXT4_IGET_HANDLE) && (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) { ret = -ESTALE; @@ -4951,11 +4944,16 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, * NeilBrown 1999oct15 */ if (inode->i_nlink == 0) { - if ((inode->i_mode == 0 || + if ((inode->i_mode == 0 || flags & EXT4_IGET_SPECIAL || !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) && ino != EXT4_BOOT_LOADER_INO) { - /* this inode is deleted */ - ret = -ESTALE; + /* this inode is deleted or unallocated */ + if (flags & EXT4_IGET_SPECIAL) { + ext4_error_inode(inode, function, line, 0, + "iget: special inode unallocated"); + ret = -EFSCORRUPTED; + } else + ret = -ESTALE; goto bad_inode; } /* The only unlinked inodes we let through here have
In ext4_fill_super(), EXT4_ORPHAN_FS flag is cleared after ext4_orphan_cleanup() is executed. Therefore, when __ext4_iget() is called to get an inode whose i_nlink is 0 when the flag exists, no error is returned. If the inode is a special inode, a null pointer dereference may occur. If the value of i_nlink is 0 for any inodes (except boot loader inodes) got by using the EXT4_IGET_SPECIAL flag, the current file system is corrupted. Therefore, make the ext4_iget() function return an error if it gets such an abnormal special inode. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199179 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216541 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216539 Reported-by: Luís Henriques <lhenriques@suse.de> Suggested-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- V1->V2: -EFSCORRUPTED is returned instead of -ESTALE for special inode errors, and the extra parentheses are removed. fs/ext4/inode.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)