From: Baokun Li libaokun1@huawei.com
hulk inclusion category: bugfix bugzilla: 187821,https://gitee.com/openeuler/kernel/issues/I5X9U0 CVE: NA
--------------------------------
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: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/ext4/ext4.h | 3 ++- fs/ext4/inode.c | 8 +++++++- 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 57169367362a..c470a5fb2f20 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2873,7 +2873,8 @@ int do_journal_get_write_access(handle_t *handle, 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 e868b33ed8f5..0f813f1cb904 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5021,8 +5021,14 @@ 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 413bf3d2f784..879e637ef3e1 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -121,7 +121,8 @@ 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);