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authorPaolo Bonzini <pbonzini@redhat.com>2012-01-12 16:01:28 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-14 15:07:24 -0800
commit0bfc96cb77224736dfa35c3c555d37b3646ef35e (patch)
treeaf5135c929ee8e1bdb38c306b2634dbc547d5189 /include/linux/blkdev.h
parent577ebb374c78314ac4617242f509e2f5e7156649 (diff)
downloadvexpress-lsk-0bfc96cb77224736dfa35c3c555d37b3646ef35e.tar.gz
block: fail SCSI passthrough ioctls on partition devices
Linux allows executing the SG_IO ioctl on a partition or LVM volume, and will pass the command to the underlying block device. This is well-known, but it is also a large security problem when (via Unix permissions, ACLs, SELinux or a combination thereof) a program or user needs to be granted access only to part of the disk. This patch lets partitions forward a small set of harmless ioctls; others are logged with printk so that we can see which ioctls are actually sent. In my tests only CDROM_GET_CAPABILITY actually occurred. Of course it was being sent to a (partition on a) hard disk, so it would have failed with ENOTTY and the patch isn't changing anything in practice. Still, I'm treating it specially to avoid spamming the logs. In principle, this restriction should include programs running with CAP_SYS_RAWIO. If for example I let a program access /dev/sda2 and /dev/sdb, it still should not be able to read/write outside the boundaries of /dev/sda2 independent of the capabilities. However, for now programs with CAP_SYS_RAWIO will still be allowed to send the ioctls. Their actions will still be logged. This patch does not affect the non-libata IDE driver. That driver however already tests for bd != bd->bd_contains before issuing some ioctl; it could be restricted further to forbid these ioctls even for programs running with CAP_SYS_ADMIN/CAP_SYS_RAWIO. Cc: linux-scsi@vger.kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: James Bottomley <JBottomley@parallels.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [ Make it also print the command name when warning - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r--include/linux/blkdev.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ca7b869508c..0ed1eb06231 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -675,6 +675,7 @@ extern int blk_insert_cloned_request(struct request_queue *q,
struct request *rq);
extern void blk_delay_queue(struct request_queue *, unsigned long);
extern void blk_recount_segments(struct request_queue *, struct bio *);
+extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
unsigned int, void __user *);
extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,