The patch titled drivers/scsi/pmcraid: reject negative request size has been added to the -mm tree. Its filename is drivers-scsi-pmcraid-reject-negative-request-size.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: drivers/scsi/pmcraid: reject negative request size From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx> 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. Something like this might do: Signed-off-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx> Cc: Anil Ravindranath <anil_ravindranath@xxxxxxxxxxxxxx> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/scsi/pmcraid.c | 3 +++ 1 file changed, 3 insertions(+) diff -puN drivers/scsi/pmcraid.c~drivers-scsi-pmcraid-reject-negative-request-size drivers/scsi/pmcraid.c --- a/drivers/scsi/pmcraid.c~drivers-scsi-pmcraid-reject-negative-request-size +++ a/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 */ _ Patches currently in -mm which might be from drosenberg@xxxxxxxxxxxxx are drivers-scsi-pmcraid-reject-negative-request-size.patch drivers-scsi-mpt2sas-mpt2sas_ctlc-fix-unbounded-copy_to_user.patch net-convert-%p-usage-to-%pk.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html