rockchip: theobroma-systems: fix modified boot_targets detection

U-Boot proper automatically modifies boot_targets to swap the order in
which MMC storage media are used for standard boot based on which MMC
storage medium was used to load U-Boot proper. This is however only done
if the user has not changed it manually, therefore a check between the
default and current value is done.

This used to work fine until the migration to standard boot where
boot_targets value size in the default environment went above the 32
characters that env_get_default function can return, thus resulting in a
truncated variable.

Therefore the check between default and current value would always fail.

By using the newly added env_get_default_into function, a buffer of
the appropriate size can be allocated on the stack to get the whole
value of boot_targets in the default environment and thus fixing the
check.

Cc: Quentin Schulz <foss+uboot@0leil.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/board/theobroma-systems/common/common.c b/board/theobroma-systems/common/common.c
index eb21d4c..864bcdd 100644
--- a/board/theobroma-systems/common/common.c
+++ b/board/theobroma-systems/common/common.c
@@ -21,7 +21,9 @@ int setup_boottargets(void)
 {
 	const char *boot_device =
 		ofnode_read_chosen_string("u-boot,spl-boot-device");
-	char *env_default, *env;
+	char env_default[sizeof(BOOT_TARGETS)];
+	char *env;
+	int ret;
 
 	if (!boot_device) {
 		debug("%s: /chosen/u-boot,spl-boot-device not set\n",
@@ -30,7 +32,9 @@ int setup_boottargets(void)
 	}
 	debug("%s: booted from %s\n", __func__, boot_device);
 
-	env_default = env_get_default("boot_targets");
+	ret = env_get_default_into("boot_targets", env_default, sizeof(env_default));
+	if (ret < 0)
+		env_default[0] = '\0';
 	env = env_get("boot_targets");
 	if (!env) {
 		debug("%s: boot_targets does not exist\n", __func__);