diff options
author | Glenn Washburn <development@efficientek.com> | 2023-08-11 16:30:04 -0500 |
---|---|---|
committer | Daniel Kiper <daniel.kiper@oracle.com> | 2023-08-14 18:04:04 +0200 |
commit | 1de58326994b0045ccfb28017d05fc1ddecdb92d (patch) | |
tree | ae25ac87e89287c35a444c267c96e15891b36369 | |
parent | 43bf0b2a10bc8f312ad4b38649c8523620d66d2b (diff) |
commands/videoinfo: Prevent crash when run while video driver already active
The videoinfo command will initialize all non-active video adapters. Video
drivers tend to zero out the global framebuffer object on initialization.
This is not a problem when there is no active video adapter. However, when
there is, then outputting to the video adapter will cause a crash because
methods in the framebuffer object are reinitialized. For example, this
command sequence will cause a crash.
terminal_output --append gfxterm; videoinfo
When running in a QEMU headless with GRUB built for the x86_64-efi target,
the first command initializes the Bochs video adapter, which, among
other things, sets the set_page() member function. Then when videoinfo is
run, all non-Bochs video adapters will be initialized, each one wiping
the framebuffer and thus setting set_page to NULL. Soon after the videoinfo
command finishes there will be a call to grub_refresh(), which will
ultimately call the framebuffer's set_page which will be NULL and cause
a crash when called.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
-rw-r--r-- | grub-core/commands/videoinfo.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/grub-core/commands/videoinfo.c b/grub-core/commands/videoinfo.c index 5eb969748..205ba78c9 100644 --- a/grub-core/commands/videoinfo.c +++ b/grub-core/commands/videoinfo.c @@ -191,6 +191,11 @@ grub_cmd_videoinfo (grub_command_t cmd __attribute__ ((unused)), /* Don't worry about errors. */ grub_errno = GRUB_ERR_NONE; } + else if (id != GRUB_VIDEO_DRIVER_NONE) + { + grub_puts_ (N_(" A video driver is active, cannot initialize this driver until it is deactivated\n")); + continue; + } else { if (adapter->init ()) |