From 27a4b6c8c1cf6c899afdd525b559b307bf21617a Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 15 May 2019 12:38:33 +0300 Subject: [PATCH] staging: vc04_services: prevent integer overflow in create_pagelist() commit ca641bae6da977d638458e78cd1487b6160a2718 upstream. The create_pagelist() "count" parameter comes from the user in vchiq_ioctl() and it could overflow. If you look at how create_page() is called in vchiq_prepare_bulk_data(), then the "size" variable is an int so it doesn't make sense to allow negatives or larger than INT_MAX. I don't know this code terribly well, but I believe that typical values of "count" are typically quite low and I don't think this check will affect normal valid uses at all. The "pagelist_size" calculation can also overflow on 32 bit systems, but not on 64 bit systems. I have added an integer overflow check for that as well. The Raspberry PI doesn't offer the same level of memory protection that x86 does so these sorts of bugs are probably not super critical to fix. Fixes: 71bad7f08641 ("staging: add bcm2708 vchiq driver") Signed-off-by: Dan Carpenter Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- .../staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c index c7c8ef6..3bece6b 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c @@ -410,9 +410,18 @@ create_pagelist(char __user *buf, size_t count, unsigned short type) int dma_buffers; dma_addr_t dma_addr; + if (count >= INT_MAX - PAGE_SIZE) + return NULL; + offset = ((unsigned int)(unsigned long)buf & (PAGE_SIZE - 1)); num_pages = DIV_ROUND_UP(count + offset, PAGE_SIZE); + if (num_pages > (SIZE_MAX - sizeof(PAGELIST_T) - + sizeof(struct vchiq_pagelist_info)) / + (sizeof(u32) + sizeof(pages[0]) + + sizeof(struct scatterlist))) + return NULL; + pagelist_size = sizeof(PAGELIST_T) + (num_pages * sizeof(u32)) + (num_pages * sizeof(pages[0]) + -- 2.7.4