[PATCH v3] boot: pxe_utils: Fix incorrect allocation of overlay_dir

[Surkov Kirill]

The function label_boot_extension() calls snprintf on a buffer
overlay_dir. However, this buffer is not initialized properly. In the
"if" branch it is initialized using a variable "len", which is smaller
than the resulting buffer. In the "else" branch this variable is not
initialized at all. This results in a crash when calling a "sysboot"
command.

This commit fixes this issue.

Signed-off-by: Surkov Kirill <fanra3.tk at gmail.com>
---
 boot/pxe_utils.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index 038416203fc..a2a9810a4cf 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -474,7 +474,7 @@ static void label_boot_extension(struct pxe_context *ctx,
 			slash = "";
 
 		dir_len = strlen(label->fdtdir) + strlen(slash) + 1;
-		overlay_dir = calloc(1, len);
+		overlay_dir = calloc(1, dir_len);
 		if (!overlay_dir)
 			return;
 
@@ -482,6 +482,9 @@ static void label_boot_extension(struct pxe_context *ctx,
 			 slash);
 	} else {
 		dir_len = 2;
+		overlay_dir = calloc(1, dir_len);
+		if (!overlay_dir)
+			return;
 		snprintf(overlay_dir, dir_len, "/");
 	}
 
-- 
2.43.0