From: Young Xiao <YangX92@xxxxxxxxxxx>
[ Upstream commit b281218ad4311a0342a40cb02fb17a363df08b48 ]
There is an out-of-bounds access to "config[len - 1]" array when the
variable "len" is zero.
See commit dada6a43b040 ("kgdboc: fix KASAN global-out-of-bounds bug
in param_set_kgdboc_var()") for details.
Signed-off-by: Young Xiao <YangX92@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/misc/kgdbts.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 99635dd9dbac..bb3a76ad80da 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -1132,7 +1132,7 @@ static void kgdbts_put_char(u8 chr)
static int param_set_kgdbts_var(const char *kmessage, struct kernel_param *kp)
{
- int len = strlen(kmessage);
+ size_t len = strlen(kmessage);
if (len >= MAX_CONFIG_LEN) {
printk(KERN_ERR "kgdbts: config string too long\n");
@@ -1152,7 +1152,7 @@ static int param_set_kgdbts_var(const char *kmessage, struct kernel_param *kp)
strcpy(config, kmessage);
/* Chop out \n char as a result of echo */
- if (config[len - 1] == '\n')
+ if (len && config[len - 1] == '\n')
config[len - 1] = '\0';
/* Go and configure with the new params. */
--
2.20.1
