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authorDan Rosenberg <drosenberg@vsecurity.com>2011-07-11 14:08:23 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:11 -0700
commit8d858047ce89c147eb9f14457cb31265967d110e (patch)
treed1e961312491518da11de81a98088bead56f2967 /drivers
parent2dee323616b55823272dc900ba09902b8febff44 (diff)
downloadlinux-linaro-stable-8d858047ce89c147eb9f14457cb31265967d110e.tar.gz
pmcraid: reject negative request size
commit b5b515445f4f5a905c5dd27e6e682868ccd6c09d upstream. There's a code path in pmcraid that can be reached via device ioctl that causes all sorts of ugliness, including heap corruption or triggering the OOM killer due to consecutive allocation of large numbers of pages. First, the user can call pmcraid_chr_ioctl(), with a type PMCRAID_PASSTHROUGH_IOCTL. This calls through to pmcraid_ioctl_passthrough(). Next, a pmcraid_passthrough_ioctl_buffer is copied in, and the request_size variable is set to buffer->ioarcb.data_transfer_length, which is an arbitrary 32-bit signed value provided by the user. If a negative value is provided here, bad things can happen. For example, pmcraid_build_passthrough_ioadls() is called with this request_size, which immediately calls pmcraid_alloc_sglist() with a negative size. The resulting math on allocating a scatter list can result in an overflow in the kzalloc() call (if num_elem is 0, the sglist will be smaller than expected), or if num_elem is unexpectedly large the subsequent loop will call alloc_pages() repeatedly, a high number of pages will be allocated and the OOM killer might be invoked. It looks like preventing this value from being negative in pmcraid_ioctl_passthrough() would be sufficient. Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/scsi/pmcraid.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 483370f1cc71..9ab8c86fc39a 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -3557,6 +3557,9 @@ static long pmcraid_ioctl_passthrough(
pmcraid_err("couldn't build passthrough ioadls\n");
goto out_free_buffer;
}
+ } else if (request_size < 0) {
+ rc = -EINVAL;
+ goto out_free_buffer;
}
/* If data is being written into the device, copy the data from user