[PATCH] boot: android: Check kcmdline's for NULL in android_image_get_kernel()

[Mattijs Korpershoek]

From: Aaron Kling <webgeek1234 at gmail.com>

kcmdline and kcmdline_extra strings can be NULL. In that case, we still
read the content from 0x00000 and pass that to the kernel, which is
completely wrong.

Fix android_image_get_kernel() to check for NULL before checking if
they are empty strings.

Fixes: 53a0ddb6d3be ("boot: android: fix extra command line support")
Signed-off-by: Aaron Kling <webgeek1234 at gmail.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
---
Thanks to Aaron for reporting this on the aosp-devs discord and for
fixing this.
---
 boot/image-android.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/boot/image-android.c b/boot/image-android.c
index 60a422dfb74a6c683b3cf9d2b19b3ad1dbd0d151..fa4e14ca4698e1dea105388dd2ea590024cafa58 100644
--- a/boot/image-android.c
+++ b/boot/image-android.c
@@ -337,12 +337,12 @@ int android_image_get_kernel(const void *hdr,
 	if (bootargs)
 		len += strlen(bootargs);
 
-	if (*img_data.kcmdline) {
+	if (img_data.kcmdline && *img_data.kcmdline) {
 		printf("Kernel command line: %s\n", img_data.kcmdline);
 		len += strlen(img_data.kcmdline) + (len ? 1 : 0); /* +1 for extra space */
 	}
 
-	if (*img_data.kcmdline_extra) {
+	if (img_data.kcmdline_extra && *img_data.kcmdline_extra) {
 		printf("Kernel extra command line: %s\n", img_data.kcmdline_extra);
 		len += strlen(img_data.kcmdline_extra) + (len ? 1 : 0); /* +1 for extra space */
 	}
@@ -357,13 +357,13 @@ int android_image_get_kernel(const void *hdr,
 	if (bootargs)
 		strcpy(newbootargs, bootargs);
 
-	if (*img_data.kcmdline) {
+	if (img_data.kcmdline && *img_data.kcmdline) {
 		if (*newbootargs) /* If there is something in newbootargs, a space is needed */
 			strcat(newbootargs, " ");
 		strcat(newbootargs, img_data.kcmdline);
 	}
 
-	if (*img_data.kcmdline_extra) {
+	if (img_data.kcmdline_extra && *img_data.kcmdline_extra) {
 		if (*newbootargs) /* If there is something in newbootargs, a space is needed */
 			strcat(newbootargs, " ");
 		strcat(newbootargs, img_data.kcmdline_extra);

---
base-commit: bc157bb6667ed97e33be8ce8436c28baa275b295
change-id: 20250113-kcmdline-extra-fix-509331e4d7f3

Best regards,
-- 
Mattijs Korpershoek <mkorpershoek at baylibre.com>