ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode

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commit 63b1e9bccb upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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This commit is contained in:

Baokun Li 2022-10-26 12:23:09 +08:00 • committed by Greg Kroah-Hartman

parent 7753d66578

commit 488a5c2bf7

3 changed files with 11 additions and 3 deletions

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3

fs/ext4/ext4.h

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8

fs/ext4/inode.c

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3

fs/ext4/ioctl.c

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