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authorDan Carpenter <dan.carpenter@oracle.com>2019-05-14 15:47:03 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-16 19:40:29 +0200
commit79e981a8503f662770ad038c7454f88421cfc882 (patch)
parent1a84219f73b2d9827a1a0612960c3d5c2c37d136 (diff)
drivers/virt/fsl_hypervisor.c: prevent integer overflow in ioctl
commit 6a024330650e24556b8a18cc654ad00cfecf6c6c upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
index 7b7f8e9a2801..1bbd910d4ddb 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 */