From 6a024330650e24556b8a18cc654ad00cfecf6c6c Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 14 May 2019 15:47:03 -0700 Subject: [PATCH] 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 Reviewed-by: Andrew Morton Cc: Timur Tabi Cc: Mihai Caraman Cc: Kumar Gala Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/virt/fsl_hypervisor.c | 3 +++ 1 file changed, 3 insertions(+) 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 */