Messages in this thread Patch in this message | | | From | B K Karthik <> | Date | Wed, 15 Jul 2020 08:50:18 -0400 | Subject | [PATCH] fs: block_dev.c: fix WARNING in submit_bio_check |
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duplicating the logic in blkdev_get_by_path to blkdev_get_by_dev to avoid a user-triggerable WARN trying to write to a read-only block device.
blkdev_get_by_path() looks at ((mode & FMODE_WRITE) && bdev_read_only(bdev)) to check for write permissions.
A user-triggerable WARN can be avoided by doing the same with bdev_get_by_dev.
Reported-by: syzbot+4c50ac32e5b10e4133e1@syzkaller.appspotmail.com Signed-off-by: B K Karthik <karthik.bk2000@live.com> --- fs/block_dev.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/block_dev.c b/fs/block_dev.c index 64c4fe8181f2..472e3b046406 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1796,6 +1796,11 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) if (err) return ERR_PTR(err); + if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { + blkdev_put(bdev, mode); + return ERR_PTR(-EACCES); + } + return bdev; } EXPORT_SYMBOL(blkdev_get_by_dev); -- 2.20.1 [unhandled content-type:application/pgp-signature] | |