From 8bd8442fec18284924e17a0fa8ef89d98b0a6d71 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 12 Jan 2012 16:01:28 +0100 Subject: block: fail SCSI passthrough ioctls on partition devices commit 0bfc96cb77224736dfa35c3c555d37b3646ef35e upstream. [ Changes with respect to 3.3: return -ENOTTY from scsi_verify_blk_ioctl and -ENOIOCTLCMD from sd_compat_ioctl. ] 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 Cc: James Bottomley Signed-off-by: Paolo Bonzini [ Make it also print the command name when warning - Linus ] Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/sd.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index c88885d..7d8b5d8 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1073,6 +1073,10 @@ static int sd_ioctl(struct block_device *bdev, fmode_t mode, SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n", disk->disk_name, cmd)); + error = scsi_verify_blk_ioctl(bdev, cmd); + if (error < 0) + return error; + /* * If we are in the middle of error recovery, don't let anyone * else try and use this device. Also, if error recovery fails, it @@ -1265,6 +1269,11 @@ static int sd_compat_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { struct scsi_device *sdev = scsi_disk(bdev->bd_disk)->device; + int ret; + + ret = scsi_verify_blk_ioctl(bdev, cmd); + if (ret < 0) + return -ENOIOCTLCMD; /* * If we are in the middle of error recovery, don't let anyone @@ -1276,8 +1285,6 @@ static int sd_compat_ioctl(struct block_device *bdev, fmode_t mode, return -ENODEV; if (sdev->host->hostt->compat_ioctl) { - int ret; - ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg); return ret; -- cgit v1.1