From 8f60fc6ec611aa6ad6fa31f3dfc8027462dbb442 Mon Sep 17 00:00:00 2001 From: Frediano Ziglio <fziglio@redhat.com> Date: Tue, 8 Sep 2015 13:06:03 +0100 Subject: [PATCH 53/57] Fix some possible overflows in red_get_string for 32 bit Signed-off-by: Frediano Ziglio <fziglio@redhat.com> Acked-by: Christophe Fergeau <cfergeau@redhat.com> --- server/red_parse_qxl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) Index: spice-0.12.5/server/red_parse_qxl.c =================================================================== --- spice-0.12.5.orig/server/red_parse_qxl.c 2015-10-01 07:18:43.117508640 -0400 +++ spice-0.12.5/server/red_parse_qxl.c 2015-10-01 07:18:43.113508672 -0400 @@ -896,6 +896,11 @@ glyphs++; glyph_size = start->height * ((start->width * bpp + 7u) / 8u); red_size += sizeof(SpiceRasterGlyph *) + SPICE_ALIGN(sizeof(SpiceRasterGlyph) + glyph_size, 4); + /* do the test correctly, we know end - start->data[0] cannot + * overflow, don't use start->data[glyph_size] to test for + * buffer overflow as this on 32 bit can cause overflow + * on the pointer arithmetic */ + spice_assert(glyph_size <= (char*) end - (char*) &start->data[0]); start = (QXLRasterGlyph*)(&start->data[glyph_size]); } spice_assert(start <= end); @@ -916,7 +921,8 @@ red_get_point_ptr(&glyph->render_pos, &start->render_pos); red_get_point_ptr(&glyph->glyph_origin, &start->glyph_origin); glyph_size = glyph->height * ((glyph->width * bpp + 7u) / 8u); - spice_assert((QXLRasterGlyph*)(&start->data[glyph_size]) <= end); + /* see above for similar test */ + spice_assert(glyph_size <= (char*) end - (char*) &start->data[0]); memcpy(glyph->data, start->data, glyph_size); start = (QXLRasterGlyph*)(&start->data[glyph_size]); glyph = (SpiceRasterGlyph*)