[PATCH] vgacon, x86/boot: Prevent faulty bootparams.screeninfo from causing harm
flat view
STALE3335d
From: Jan H. Schönherr <hidden>
Date: 2017-08-27 13:56:46
Subsystem:
console subsystem, framebuffer layer, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Greg Kroah-Hartman, Helge Deller, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
If a zero for the number of colums or rows manages to slip through, gotoxy() will underflow vc->vc_pos, causing the next action on the referenced memory to end with a page fault. Make the check in vgacon more pessimistic to prevent that. Also change a similar check in the x86 boot code with a similar problem. Signed-off-by: Jan H. Schönherr <redacted> --- Let me know, if I should split this into two patches. arch/x86/boot/compressed/misc.c | 3 +-- drivers/video/console/vgacon.c | 5 ++--- 2 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index a0838ab..c14217c 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c@@ -116,8 +116,7 @@ void __putstr(const char *s) } } - if (boot_params->screen_info.orig_video_mode = 0 && - lines = 0 && cols = 0) + if (lines = 0 || cols = 0) return; x = boot_params->screen_info.orig_x;
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index dc06cb6..445b1dc 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c@@ -398,9 +398,8 @@ static const char *vgacon_startup(void) #endif } - /* boot_params.screen_info initialized? */ - if ((screen_info.orig_video_mode = 0) && - (screen_info.orig_video_lines = 0) && + /* boot_params.screen_info reasonably initialized? */ + if ((screen_info.orig_video_lines = 0) || (screen_info.orig_video_cols = 0)) goto no_vga;
--
2.3.1.dirty