zboot: [PATCH] boot/pxe-utils: populate initrd_filesize for extlinux boot

[Ryan Lahfa]

The reason for this is that initrd_filesize is constantly equal to zero
or more specifically, potentially uninitialized memory.

I believe this was introduced in
085cbdafca9c3d7bc2f27523a343f61db82f2ccb ("pxe: simplify label_boot()"),
diff here:

diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index b08aee9896..defbe465e4 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -532,11 +532,10 @@ static int label_boot(struct pxe_context *ctx, struct pxe_label *label)
 		}
 
 		initrd_addr_str = env_get("ramdisk_addr_r");
-		strcpy(initrd_filesize, simple_xtoa(size));
-
-		strncpy(initrd_str, initrd_addr_str, 18);
-		strcat(initrd_str, ":");
-		strncat(initrd_str, initrd_filesize, 9);
+		size = snprintf(initrd_str, sizeof(initrd_str), "%s:%lx",
+				initrd_addr_str, size);
+		if (size >= sizeof(initrd_str))
+			return 1;
 	}
 
 	if (get_relfile_envaddr(ctx, label->kernel, "kernel_addr_r",

The initrd_filesize completely disappears.

We re-copy the size information inside initrd_filesize, maybe, too
naively, something may have to be done to reduce the overflow potential
if it exist at all.

pxe_utils.c |    2 ++
 1 file changed, 2 insertions(+)