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authorDan Rosenberg <drosenberg@vsecurity.com>2011-04-05 13:27:31 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:06:35 -0700
commitcf546a1fd7fd736f1cd471f059900d477a4b7096 (patch)
treefd3e1858d52e9cc306d05025f70a78b9f95c8fc7 /drivers
parent60584ef99395a89d136399bbc127289a4aa29dc7 (diff)
downloadlinux-linaro-android-cf546a1fd7fd736f1cd471f059900d477a4b7096.tar.gz
pmcraid: reject negative request size
commit 5f6279da3760ce48f478f2856aacebe0c59a39f3 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. Not especially relevant from a security perspective, since users must have CAP_SYS_ADMIN to open the character device. First, the user can call pmcraid_chr_ioctl() with a type PMCRAID_PASSTHROUGH_IOCTL. 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. Prevent this value from being negative in pmcraid_ioctl_passthrough(). Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Cc: Anil Ravindranath <anil_ravindranath@pmc-sierra.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de> 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 321cf3ae863..ce0701d512f 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -3814,6 +3814,9 @@ static long pmcraid_ioctl_passthrough(
rc = -EFAULT;
goto out_free_buffer;
}
+ } else if (request_size < 0) {
+ rc = -EINVAL;
+ goto out_free_buffer;
}
/* check if we have any additional command parameters */