kexec/uImage: probe to identify a corrupted image

Teach uImage_probe_xxx() to return the information about
a corrupted image. This is required to prevent the loading
of a corrupted ramdisk, where we don't have strict checking
for the other formats, unlike the kernel. So, we should abort
the operation than causing a problem with the new kernel.

Without this patch, a corrupted uImage ramdisk is treated as
a plain ramdisk where there is no format check involved.

# kexec -l uImage --initrd romfs-initrd.corrupt
The data CRC does not match. Computed: 867e73f7 expected 8f097cc0
# echo $?
0
# kexec -e
Starting new kernel
Bye!
Reserving 55MB of memory at 70MB for crashkernel (System RAM: 256MB)
Using Xilinx Virtex440 machine description
Linux version 3.6.0-rc3 (root@suzukikp) (gcc version 4.3.4 [gcc-4_3-branch revision 152973] (GCC) ) #66 Tue Apr 16 06:36:56 UTC 2013
Found initrd at 0xcf5f8000:0xcfff8040
...

NET: Registered protocol family 17
RAMDISK: Couldn't find valid RAM disk image starting at 0.
List of all partitions:
No filesystem could mount root, tried:  ext2 cramfs
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1,0)

With this patch :

# kexec -l uImage --initrd romfs-initrd.corrupt
uImage: The data CRC does not match. Computed: 867e73f7 expected 8f097cc0
uImage: Corrupted ramdisk file romfs-initrd

With a corrupted kernel image(the behaviour remains the same) :
# kexec -l uImage.corrupt --initrd romfs-initrd
uImage: The data CRC does not match. Computed: 285787b7 expected e37f65ad
Cannot determine the file type of uImage.corrupt

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 7 insertions, 2 deletions

diff --git a/kexec/arch/ppc/kexec-uImage-ppc.c b/kexec/arch/ppc/kexec-uImage-ppc.c
index 008463b..83a7a5f 100644
--- a/kexec/arch/ppc/kexec-uImage-ppc.c
+++ b/kexec/arch/ppc/kexec-uImage-ppc.c
@@ -56,10 +56,15 @@ char *slurp_ramdisk_ppc(const char *filename, off_t *r_size)
 	struct Image_info img;
 	off_t size;
 	const unsigned char *buf = slurp_file(filename, &size);
+	int rc;
 
 	/* Check if this is a uImage RAMDisk */
-	if (buf &&
-	    uImage_probe_ramdisk(buf, size, IH_ARCH_PPC) == 0) {
+	if (!buf)
+		return buf;
+	rc = uImage_probe_ramdisk(buf, size, IH_ARCH_PPC); 
+	if (rc < 0)
+		die("uImage: Corrupted ramdisk file %s\n", filename);
+	else if (rc == 0) {
 		if (uImage_load(buf, size, &img) != 0)
 			die("uImage: Reading %ld bytes from %s failed\n",
 				size, filename);