diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2013-03-01 22:45:44 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-08 07:29:43 -0800 |
| commit | d8b8a43e0f3c99bb29f258ef508969793f8e43bd (patch) | |
| tree | 275f0d0bfedf91eed51f22c7be6bed227cbf5b77 /drivers/md/dm-delay.c | |
| parent | 9e23d8bd64e49062faf4aa4abcedd3943cf1d09d (diff) | |
dm: fix truncated status strings
commit fd7c092e711ebab55b2688d3859d95dfd0301f73 upstream.
Avoid returning a truncated table or status string instead of setting
the DM_BUFFER_FULL_FLAG when the last target of a table fills the
buffer.
When processing a table or status request, the function retrieve_status
calls ti->type->status. If ti->type->status returns non-zero,
retrieve_status assumes that the buffer overflowed and sets
DM_BUFFER_FULL_FLAG.
However, targets don't return non-zero values from their status method
on overflow. Most targets returns always zero.
If a buffer overflow happens in a target that is not the last in the
table, it gets noticed during the next iteration of the loop in
retrieve_status; but if a buffer overflow happens in the last target, it
goes unnoticed and erroneously truncated data is returned.
In the current code, the targets behave in the following way:
* dm-crypt returns -ENOMEM if there is not enough space to store the
key, but it returns 0 on all other overflows.
* dm-thin returns errors from the status method if a disk error happened.
This is incorrect because retrieve_status doesn't check the error
code, it assumes that all non-zero values mean buffer overflow.
* all the other targets always return 0.
This patch changes the ti->type->status function to return void (because
most targets don't use the return code). Overflow is detected in
retrieve_status: if the status method fills up the remaining space
completely, it is assumed that buffer overflow happened.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md/dm-delay.c')
| -rw-r--r-- | drivers/md/dm-delay.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c index 2dc22dddb2ae..ee99912596cb 100644 --- a/drivers/md/dm-delay.c +++ b/drivers/md/dm-delay.c @@ -294,8 +294,8 @@ static int delay_map(struct dm_target *ti, struct bio *bio, return delay_bio(dc, dc->read_delay, bio); } -static int delay_status(struct dm_target *ti, status_type_t type, - char *result, unsigned maxlen) +static void delay_status(struct dm_target *ti, status_type_t type, + char *result, unsigned maxlen) { struct delay_c *dc = ti->private; int sz = 0; @@ -315,8 +315,6 @@ static int delay_status(struct dm_target *ti, status_type_t type, dc->write_delay); break; } - - return 0; } static int delay_iterate_devices(struct dm_target *ti, |