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authorDan Carpenter <dan.carpenter@oracle.com>2019-05-14 15:47:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:52 -0700
commit6a024330650e24556b8a18cc654ad00cfecf6c6c (patch)
treeeba90968fd5b597b489649def7ad4a6d0d0e5aeb
parentc8ea3663f7a8e6996d44500ee818c9330ac4fd88 (diff)
download96b-common-6a024330650e24556b8a18cc654ad00cfecf6c6c.tar.gz
drivers/virt/fsl_hypervisor.c: prevent integer overflow in ioctl
The "param.count" value is a u64 thatcomes from the user. The code later in the function assumes that param.count is at least one and if it's not then it leads to an Oops when we dereference the ZERO_SIZE_PTR. Also the addition can have an integer overflow which would lead us to allocate a smaller "pages" array than required. I can't immediately tell what the possible run times implications are, but it's safest to prevent the overflow. Link: http://lkml.kernel.org/r/20181218082129.GE32567@kadam Fixes: 6db7199407ca ("drivers/virt: introduce Freescale hypervisor management driver") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Timur Tabi <timur@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/virt/fsl_hypervisor.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
index a41431edbf25..93d5bebf9572 100644
--- a/drivers/virt/fsl_hypervisor.c
+++ b/drivers/virt/fsl_hypervisor.c
@@ -215,6 +215,9 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
* hypervisor.
*/
lb_offset = param.local_vaddr & (PAGE_SIZE - 1);
+ if (param.count == 0 ||
+ param.count > U64_MAX - lb_offset - PAGE_SIZE + 1)
+ return -EINVAL;
num_pages = (param.count + lb_offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
/* Allocate the buffers we need */