The user may use the fbcon=vc:<n1>-<n2> option to tell fbcon to take
over the given range (n1...n2) of consoles. The value for n1 and n2
needs to be a positive number and up to (MAX_NR_CONSOLES - 1).
The given values were not fully checked against those boundaries yet.
To fix the issue, convert first_fb_vc and last_fb_vc to unsigned
integers and check them against the upper boundary, and make sure that
first_fb_vc is smaller than last_fb_vc.
Signed-off-by: Helge Deller <deller@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 2fc1b80a26ad..c2f9e5711c39 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -115,8 +115,8 @@ static int logo_lines;
enums. */
static int logo_shown = FBCON_LOGO_CANSHOW;
/* console mappings */
-static int first_fb_vc;
-static int last_fb_vc = MAX_NR_CONSOLES - 1;
+static unsigned int first_fb_vc;
+static unsigned int last_fb_vc = MAX_NR_CONSOLES - 1;
static int fbcon_is_default = 1;
static int primary_device = -1;
static int fbcon_has_console_bind;
@@ -464,10 +464,12 @@ static int __init fb_console_setup(char *this_opt)
options += 3;
if (*options)
first_fb_vc = simple_strtoul(options, &options, 10) - 1;
- if (first_fb_vc < 0)
+ if (first_fb_vc >= MAX_NR_CONSOLES)
first_fb_vc = 0;
if (*options++ == '-')
last_fb_vc = simple_strtoul(options, &options, 10) - 1;
+ if (last_fb_vc < first_fb_vc || last_fb_vc >= MAX_NR_CONSOLES)
+ last_fb_vc = MAX_NR_CONSOLES - 1;
fbcon_is_default = 0;
continue;
}
