Messages in this thread | | | Date | Mon, 15 Nov 2010 07:56:05 +0100 | Subject | Re: [patch 2/2] fbcmap: integer overflow bug | From | Geert Uytterhoeven <> |
| |
On Mon, Nov 15, 2010 at 05:48, Paul Mundt <lethal@linux-sh.org> wrote: > On Sat, Nov 13, 2010 at 01:07:18PM +0300, Dan Carpenter wrote: >> @@ -256,8 +264,12 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info) >> int rc, size = cmap->len * sizeof(u16); >> struct fb_cmap umap; >> >> + if (cmap->len * 2 > INT_MAX)
Isn't that another integer overflow? I.e. should be "if (cmap->len > INT_MAX / sizeof(u16))" instead?
>> + return -EINVAL; >> + >> memset(&umap, 0, sizeof(struct fb_cmap)); >> - rc = fb_alloc_cmap(&umap, cmap->len, cmap->transp != NULL); >> + rc = fb_alloc_cmap_gfp(&umap, cmap->len, cmap->transp != NULL, >> + GFP_KERNEL); >> if (rc) >> return rc; >> if (copy_from_user(umap.red, cmap->red, size) || > > This looks reasonable, but it probably makes more sense to use -E2BIG > for the overflow case (as other cases are doing already), and also just > to check size directly rather than open-coding the * 2.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |