[PATCH RESEND] floppy: fix open(O_ACCMODE) for ioctl-only open

Jiri Kosina
2016-06-30T11:18:24Z

From: Jiri Kosina <jkosina@suse.cz>

Commit 09954bad4 ("floppy: refactor open() flags handling"), as a
side-effect, causes open(/dev/fdX, O_ACCMODE) to fail. It turns out that
this is being used setfdprm userspace for ioctl-only open().

Reintroduce back the original behavior wrt !(FMODE_READ|FMODE_WRITE)
modes, while still keeping the original O_NDELAY bug fixed.

Cc: stable@vger.kernel.org # v4.5+
Reported-by: Wim Osterholt <wim@djo.tudelft.nl>
Tested-by: Wim Osterholt <wim@djo.tudelft.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

Jens, this should preferably go into 4.7-rcX and to -stable as well.

drivers/block/floppy.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 84708a5..a1dcf12 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3663,11 +3663,6 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)

opened_bdev[drive] = bdev;

- if (!(mode & (FMODE_READ|FMODE_WRITE))) {
- res = -EINVAL;
- goto out;
- }
-
res = -ENXIO;

if (!floppy_track_buffer) {
@@ -3711,13 +3706,15 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
if (UFDCS->rawcmd == 1)
UFDCS->rawcmd = 2;

- UDRS->last_checked = 0;
- clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
- check_disk_change(bdev);
- if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
- goto out;
- if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags))
- goto out;
+ if (mode & (FMODE_READ|FMODE_WRITE)) {
+ UDRS->last_checked = 0;
+ clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
+ check_disk_change(bdev);
+ if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
+ goto out;
+ if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags))
+ goto out;
+ }

res = -EROFS;

--
Jiri Kosina
SUSE Labs