From 309eca4e0a31ea70dcc844812691439312dad091 Mon Sep 17 00:00:00 2001 From: Ken Sharp Date: Mon, 20 Mar 2017 09:34:11 +0000 Subject: [PATCH] Ensure a device has raster memory, before trying to read it. Bug #697676 "Null pointer dereference in mem_get_bits_rectangle()" This is only possible by abusing/mis-using Ghostscript-specific language extensions, so cannot happen in a general PostScript program. Nevertheless, Ghostscript should not crash. So this commit checks the memory device to see if raster memory has been allocated, before trying to read from it. --- base/gdevmem.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/base/gdevmem.c b/base/gdevmem.c index afd05bd..d52d684 100644 --- a/base/gdevmem.c +++ b/base/gdevmem.c @@ -606,6 +606,8 @@ mem_get_bits_rectangle(gx_device * dev, const gs_int_rect * prect, GB_PACKING_CHUNKY | GB_COLORS_NATIVE | GB_ALPHA_NONE; return_error(gs_error_rangecheck); } + if (mdev->line_ptrs == 0x00) + return_error(gs_error_rangecheck); if ((w <= 0) | (h <= 0)) { if ((w | h) < 0) return_error(gs_error_rangecheck); -- 2.9.1