Some SCSI commands can be sent to disks via SG_IO even by unprivileged
users. Unfortunately, some opcodes overlap across SCSI device classes
and have different meanings for different classes. Four of them can
be used for read-only file descriptors on MMC, but should be limited to
descriptors opened for read-write on SBC:
The current bitmap of allowed commands is designed for MMC devices
(roughly, "play/burn CDs without requiring root").
- READ SUBCHANNEL <-> UNMAP (destructive, but no control on written
data)
- GET PERFORMANCE <-> ERASE (not really a problem, no one supports
ERASE anyway)
- READ DISC INFORMATION <-> XPWRITE (not commonly implemented but
most dangerous)
- PLAY AUDIO TI <-> SANITIZE (a very new command)
To fix this, the series splits the bitmap entries for these four
commands into two entries, one read-only for MMC and one read-write
for the other device classes.
Cc: "James E.J. Bottomley" <jbottom...@parallels.com>
Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
block/scsi_ioctl.c | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index c4c42dd..7ea3428 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -182,29 +182,33 @@ static void blk_set_cmd_filter_defaults(struct
blk_cmd_filter *filter)
sgio_bitmap_set(0x2E, D| W|R|O| B|K , write); /* WRITE
AND VERIFY(10) */
sgio_bitmap_set(0x35, D| W|R|O| B|K , write); /*
SYNCHRONIZE CACHE(10) */
sgio_bitmap_set(0x3F, D| W| O , write); /* WRITE
LONG(10) */
+ sgio_bitmap_set(0x42, D , write); /* UNMAP
*/
+ sgio_bitmap_set(0x48, D| B , write); /*
SANITIZE */
+ sgio_bitmap_set(0x51, D , write); /*
XPWRITE(10) */
sgio_bitmap_set(0x8A, D|T| W| O| B , write); /*
WRITE(16) */
sgio_bitmap_set(0xAA, D| W|R|O| C , write); /*
WRITE(12) */
+ sgio_bitmap_set(0xAC, O , write); /*
ERASE(12) */
sgio_bitmap_set(0xAE, D| W| O , write); /* WRITE
AND VERIFY(12) */
sgio_bitmap_set(0xEA, D| W| O , write); /*
WRITE_LONG_2 ?? */
/* (mostly) MMC */
sgio_bitmap_set(0x23, R , read); /* READ
FORMAT CAPACITIES */
- sgio_bitmap_set(0x42, D| R , read); /* READ
SUB-CHANNEL / UNMAP !! */
+ sgio_bitmap_set(0x42, R , read); /* READ
SUB-CHANNEL */
sgio_bitmap_set(0x43, R , read); /* READ
TOC/PMA/ATIP */
sgio_bitmap_set(0x44, T| R| V , read); /* READ
HEADER */
sgio_bitmap_set(0x45, R , read); /* PLAY
AUDIO(10) */
sgio_bitmap_set(0x46, R , read); /* GET
CONFIGURATION */
sgio_bitmap_set(0x47, R , read); /* PLAY
AUDIO MSF */
- sgio_bitmap_set(0x48, D| R| B , read); /* PLAY
AUDIO TI / SANITIZE !! */
+ sgio_bitmap_set(0x48, R , read); /* PLAY
AUDIO TI */
sgio_bitmap_set(0x4A, R , read); /* GET
EVENT STATUS NOTIFICATION */
sgio_bitmap_set(0x4B, R , read); /*
PAUSE/RESUME */
sgio_bitmap_set(0x4E, R , read); /* STOP
PLAY/SCAN */
- sgio_bitmap_set(0x51, D| R , read); /* READ
DISC INFORMATION / XPWRITE(10) !! */
+ sgio_bitmap_set(0x51, R , read); /* READ
DISC INFORMATION */
sgio_bitmap_set(0x52, R , read); /* READ
TRACK INFORMATION */
sgio_bitmap_set(0x5C, R , read); /* READ
BUFFER CAPACITY */
sgio_bitmap_set(0xA4, R , read); /*
REPORT KEY */
- sgio_bitmap_set(0xAC, R|O , read); /* GET
PERFORMANCE / ERASE !! */
+ sgio_bitmap_set(0xAC, R , read); /* GET
PERFORMANCE */
sgio_bitmap_set(0xAD, R , read); /* READ
DVD STRUCTURE */
sgio_bitmap_set(0xB9, R , read); /* READ
CD MSF */
sgio_bitmap_set(0xBA, R , read); /* SCAN
*/
--
1.7.1
--
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