* [PATCH] video: fbdev: vermilion: use 64-bit arithmetic instead of 32-bit @ 2018-02-07 0:04 ` Gustavo A. R. Silva 2018-03-12 15:58 ` Bartlomiej Zolnierkiewicz 0 siblings, 1 reply; 2+ messages in thread From: Gustavo A. R. Silva @ 2018-02-07 0:04 UTC (permalink / raw) To: Bartlomiej Zolnierkiewicz Cc: dri-devel, linux-fbdev, linux-kernel, Gustavo A. R. Silva Cast _pitch_ to u64 in order to give the compiler complete information about the proper arithmetic to use. Notice that this variable is being used in a context that expects an expression of type u64 (64 bits, unsigned). The expression pitch * var->yres_virtual is currently being evaluated using 32-bit arithmetic and the result of the operation is being stored into variable mem, which is a variable of type u64. Based on that, chances are there is a potential integer overflow as a result of the operation. Addresses-Coverity-ID: 200655 ("Unintentional integer overflow") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/video/fbdev/vermilion/vermilion.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/vermilion/vermilion.c b/drivers/video/fbdev/vermilion/vermilion.c index 6f8d444..5172fa5 100644 --- a/drivers/video/fbdev/vermilion/vermilion.c +++ b/drivers/video/fbdev/vermilion/vermilion.c @@ -651,7 +651,7 @@ static int vmlfb_check_var_locked(struct fb_var_screeninfo *var, } pitch = ALIGN((var->xres * var->bits_per_pixel) >> 3, 0x40); - mem = pitch * var->yres_virtual; + mem = (u64)pitch * var->yres_virtual; if (mem > vinfo->vram_contig_size) { return -ENOMEM; } -- 2.7.4 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] video: fbdev: vermilion: use 64-bit arithmetic instead of 32-bit 2018-02-07 0:04 ` [PATCH] video: fbdev: vermilion: use 64-bit arithmetic instead of 32-bit Gustavo A. R. Silva @ 2018-03-12 15:58 ` Bartlomiej Zolnierkiewicz 0 siblings, 0 replies; 2+ messages in thread From: Bartlomiej Zolnierkiewicz @ 2018-03-12 15:58 UTC (permalink / raw) To: Gustavo A. R. Silva Cc: linux-fbdev, Gustavo A. R. Silva, linux-kernel, dri-devel On Tuesday, February 06, 2018 06:04:24 PM Gustavo A. R. Silva wrote: > Cast _pitch_ to u64 in order to give the compiler complete information > about the proper arithmetic to use. Notice that this variable is > being used in a context that expects an expression of type u64 > (64 bits, unsigned). > > The expression pitch * var->yres_virtual is currently being evaluated > using 32-bit arithmetic and the result of the operation is being stored > into variable mem, which is a variable of type u64. Based on that, > chances are there is a potential integer overflow as a result of the > operation. > > Addresses-Coverity-ID: 200655 ("Unintentional integer overflow") > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Patch queued for 4.17, thanks. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2018-03-12 15:58 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <CGME20180207000429epcas3p49ce7f7528d02b9799713e8806d77847d@epcas3p4.samsung.com>
2018-02-07 0:04 ` [PATCH] video: fbdev: vermilion: use 64-bit arithmetic instead of 32-bit Gustavo A. R. Silva
2018-03-12 15:58 ` Bartlomiej Zolnierkiewicz
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).