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path: root/drivers/md/dm-verity.c
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2013-03-01dm: fix truncated status stringsMikulas Patocka
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. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-12-21dm: remove map_infoMikulas Patocka
This patch removes map_info from bio-based device mapper targets. map_info is still used for request-based targets. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-12-21dm verity: use per_bio_dataMikulas Patocka
Replace io_mempool with per_bio_data in dm-verity. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-10-12dm: use ACCESS_ONCE for sysfs valuesMikulas Patocka
Use the ACCESS_ONCE macro in dm-bufio and dm-verity where a variable can be modified asynchronously (through sysfs) and we want to prevent compiler optimizations that assume that the variable hasn't changed. (See Documentation/atomic_ops.txt.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-09-26dm verity: fix overflow checkMikulas Patocka
This patch fixes sector_t overflow checking in dm-verity. Without this patch, the code checks for overflow only if sector_t is smaller than long long, not if sector_t and long long have the same size. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-07-27dm thin: commit before gathering statusAlasdair G Kergon
Commit outstanding metadata before returning the status for a dm thin pool so that the numbers reported are as up-to-date as possible. The commit is not performed if the device is suspended or if the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target through a new 'status_flags' parameter in the target's dm_status_fn. The userspace dmsetup tool will support the --noflush flag with the 'dmsetup status' and 'dmsetup wait' commands from version 1.02.76 onwards. Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28dm: add verity targetMikulas Patocka
This device-mapper target creates a read-only device that transparently validates the data on one underlying device against a pre-generated tree of cryptographic checksums stored on a second device. Two checksum device formats are supported: version 0 which is already shipping in Chromium OS and version 1 which incorporates some improvements. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Signed-off-by: Will Drewry <wad@chromium.org> Signed-off-by: Elly Jones <ellyjones@chromium.org> Cc: Milan Broz <mbroz@redhat.com> Cc: Olof Johansson <olofj@chromium.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>