From 08e098b1dbf01e96376f594b337491bc4cfa48dd Mon Sep 17 00:00:00 2001 From: Darren Kenny Date: Wed, 4 Nov 2020 14:43:44 +0000 Subject: [PATCH] video/fb/video_fb: Fix multiple integer overflows The calculation of the unsigned 64-bit value is being generated by multiplying 2, signed or unsigned, 32-bit integers which may overflow before promotion to unsigned 64-bit. Fix all of them. Fixes: CID 73703, CID 73767, CID 73833 Signed-off-by: Darren Kenny Reviewed-by: Daniel Kiper Signed-off-by: Stefan Sørensen --- grub-core/video/fb/video_fb.c | 52 ++++++++++++++++++++++++++++++------------- 1 file changed, 36 insertions(+), 16 deletions(-) diff --git a/grub-core/video/fb/video_fb.c b/grub-core/video/fb/video_fb.c index 1a602c8..1c9a138 100644 --- a/grub-core/video/fb/video_fb.c +++ b/grub-core/video/fb/video_fb.c @@ -25,6 +25,7 @@ #include #include #include +#include GRUB_MOD_LICENSE ("GPLv3+"); @@ -1417,15 +1418,23 @@ doublebuf_blit_update_screen (void) { if (framebuffer.current_dirty.first_line <= framebuffer.current_dirty.last_line) - grub_memcpy ((char *) framebuffer.pages[0] - + framebuffer.current_dirty.first_line - * framebuffer.back_target->mode_info.pitch, - (char *) framebuffer.back_target->data - + framebuffer.current_dirty.first_line - * framebuffer.back_target->mode_info.pitch, - framebuffer.back_target->mode_info.pitch - * (framebuffer.current_dirty.last_line - - framebuffer.current_dirty.first_line)); + { + grub_size_t copy_size; + + if (grub_sub (framebuffer.current_dirty.last_line, + framebuffer.current_dirty.first_line, ©_size) || + grub_mul (framebuffer.back_target->mode_info.pitch, copy_size, ©_size)) + { + /* Shouldn't happen, but if it does we've a bug. */ + return GRUB_ERR_BUG; + } + + grub_memcpy ((char *) framebuffer.pages[0] + framebuffer.current_dirty.first_line * + framebuffer.back_target->mode_info.pitch, + (char *) framebuffer.back_target->data + framebuffer.current_dirty.first_line * + framebuffer.back_target->mode_info.pitch, + copy_size); + } framebuffer.current_dirty.first_line = framebuffer.back_target->mode_info.height; framebuffer.current_dirty.last_line = 0; @@ -1439,7 +1448,7 @@ grub_video_fb_doublebuf_blit_init (struct grub_video_fbrender_target **back, volatile void *framebuf) { grub_err_t err; - grub_size_t page_size = mode_info.pitch * mode_info.height; + grub_size_t page_size = (grub_size_t) mode_info.pitch * mode_info.height; framebuffer.offscreen_buffer = grub_zalloc (page_size); if (! framebuffer.offscreen_buffer) @@ -1482,12 +1491,23 @@ doublebuf_pageflipping_update_screen (void) last_line = framebuffer.previous_dirty.last_line; if (first_line <= last_line) - grub_memcpy ((char *) framebuffer.pages[framebuffer.render_page] - + first_line * framebuffer.back_target->mode_info.pitch, - (char *) framebuffer.back_target->data - + first_line * framebuffer.back_target->mode_info.pitch, - framebuffer.back_target->mode_info.pitch - * (last_line - first_line)); + { + grub_size_t copy_size; + + if (grub_sub (last_line, first_line, ©_size) || + grub_mul (framebuffer.back_target->mode_info.pitch, copy_size, ©_size)) + { + /* Shouldn't happen, but if it does we've a bug. */ + return GRUB_ERR_BUG; + } + + grub_memcpy ((char *) framebuffer.pages[framebuffer.render_page] + first_line * + framebuffer.back_target->mode_info.pitch, + (char *) framebuffer.back_target->data + first_line * + framebuffer.back_target->mode_info.pitch, + copy_size); + } + framebuffer.previous_dirty = framebuffer.current_dirty; framebuffer.current_dirty.first_line = framebuffer.back_target->mode_info.height; -- 2.14.2