doc: Replace examples of MD5 and SHA1 with SHA256
Both SHA1 and (especially) MD5 are no longer as safe as they once were for
cryptographic use. Replaces examples which use them with examples using
SHA256 instead. This will provide more-secure defaults for users who use
documentation examples as a base for their own use. This is not too
necessary for non-verified-boot scenarios (since someone could just replace
the checksum), but I wanted to be complete.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/doc/usage/fit/beaglebone_vboot.rst b/doc/usage/fit/beaglebone_vboot.rst
index a102be1..cd6bb14 100644
--- a/doc/usage/fit/beaglebone_vboot.rst
+++ b/doc/usage/fit/beaglebone_vboot.rst
@@ -145,7 +145,7 @@
load = <0x80008000>;
entry = <0x80008000>;
hash-1 {
- algo = "sha1";
+ algo = "sha256";
};
};
fdt-1 {
@@ -155,7 +155,7 @@
arch = "arm";
compression = "none";
hash-1 {
- algo = "sha1";
+ algo = "sha256";
};
};
};
@@ -165,7 +165,7 @@
kernel = "kernel";
fdt = "fdt-1";
signature-1 {
- algo = "sha1,rsa2048";
+ algo = "sha256,rsa2048";
key-name-hint = "dev";
sign-images = "fdt", "kernel";
};
@@ -227,8 +227,8 @@
OS: Linux
Load Address: 0x80008000
Entry Point: 0x80008000
- Hash algo: sha1
- Hash value: c94364646427e10f423837e559898ef02c97b988
+ Hash algo: sha256
+ Hash value: 51b2adf9c1016ed46f424d85dcc6c34c46a20b9bee7227e06a6b6320ca5d35c1
Image 1 (fdt-1)
Description: beaglebone-black
Created: Sun Jun 1 12:50:30 2014
@@ -236,8 +236,8 @@
Compression: uncompressed
Data Size: 31547 Bytes = 30.81 kB = 0.03 MB
Architecture: ARM
- Hash algo: sha1
- Hash value: cb09202f889d824f23b8e4404b781be5ad38a68d
+ Hash algo: sha256
+ Hash value: 807d5842a04132261ba092373bd40c78991bc7ce173d1175cd976ec37858e7cd
Default Configuration: 'conf-1'
Configuration 0 (conf-1)
Description: unavailable
@@ -255,11 +255,11 @@
which results in::
- Verifying Hash Integrity ... sha1,rsa2048:dev+
+ Verifying Hash Integrity ... sha256,rsa2048:dev+
## Loading kernel from FIT Image at 7fc6ee469000 ...
Using 'conf-1' configuration
Verifying Hash Integrity ...
- sha1,rsa2048:dev+
+ sha256,rsa2048:dev+
OK
Trying 'kernel' kernel subimage
@@ -272,10 +272,10 @@
OS: Linux
Load Address: 0x80008000
Entry Point: 0x80008000
- Hash algo: sha1
- Hash value: c94364646427e10f423837e559898ef02c97b988
+ Hash algo: sha256
+ Hash value: 51b2adf9c1016ed46f424d85dcc6c34c46a20b9bee7227e06a6b6320ca5d35c1
Verifying Hash Integrity ...
- sha1+
+ sha256+
OK
Unimplemented compression type 4
@@ -288,10 +288,10 @@
Compression: uncompressed
Data Size: 31547 Bytes = 30.81 kB = 0.03 MB
Architecture: ARM
- Hash algo: sha1
- Hash value: cb09202f889d824f23b8e4404b781be5ad38a68d
+ Hash algo: sha256
+ Hash value: 807d5842a04132261ba092373bd40c78991bc7ce173d1175cd976ec37858e7cd
Verifying Hash Integrity ...
- sha1+
+ sha256+
OK
Loading Flat Device Tree ... OK
@@ -303,14 +303,14 @@
Signature check OK
-At the top, you see "sha1,rsa2048:dev+". This means that it checked an RSA key
-of size 2048 bits using SHA1 as the hash algorithm. The key name checked was
+At the top, you see "sha256,rsa2048:dev+". This means that it checked an RSA key
+of size 2048 bits using SHA256 as the hash algorithm. The key name checked was
'dev' and the '+' means that it verified. If it showed '-' that would be bad.
Once the configuration is verified it is then possible to rely on the hashes
in each image referenced by that configuration. So fit_check_sign goes on to
load each of the images. We have a kernel and an FDT but no ramkdisk. In each
-case fit_check_sign checks the hash and prints sha1+ meaning that the SHA1
+case fit_check_sign checks the hash and prints sha256+ meaning that the SHA256
hash verified. This means that none of the images has been tampered with.
There is a test in test/vboot which uses U-Boot's sandbox build to verify that
@@ -328,11 +328,11 @@
and extends for about 7MB. Try changing a byte at 0x2000 (say) and run
fit_check_sign again. You should see something like::
- Verifying Hash Integrity ... sha1,rsa2048:dev+
+ Verifying Hash Integrity ... sha256,rsa2048:dev+
## Loading kernel from FIT Image at 7f5a39571000 ...
Using 'conf-1' configuration
Verifying Hash Integrity ...
- sha1,rsa2048:dev+
+ sha256,rsa2048:dev+
OK
Trying 'kernel' kernel subimage
@@ -345,10 +345,10 @@
OS: Linux
Load Address: 0x80008000
Entry Point: 0x80008000
- Hash algo: sha1
- Hash value: c94364646427e10f423837e559898ef02c97b988
+ Hash algo: sha256
+ Hash value: 51b2adf9c1016ed46f424d85dcc6c34c46a20b9bee7227e06a6b6320ca5d35c1
Verifying Hash Integrity ...
- sha1 error
+ sha256 error
Bad hash value for 'hash-1' hash node in 'kernel' image node
Bad Data Hash
@@ -361,10 +361,10 @@
Compression: uncompressed
Data Size: 31547 Bytes = 30.81 kB = 0.03 MB
Architecture: ARM
- Hash algo: sha1
- Hash value: cb09202f889d824f23b8e4404b781be5ad38a68d
+ Hash algo: sha256
+ Hash value: 807d5842a04132261ba092373bd40c78991bc7ce173d1175cd976ec37858e7cd
Verifying Hash Integrity ...
- sha1+
+ sha256+
OK
Loading Flat Device Tree ... OK
@@ -419,13 +419,13 @@
the hash::
fdtget -tx image.fit /images/kernel/hash-1 value
- c9436464 6427e10f 423837e5 59898ef0 2c97b988
- fdtput -tx image.fit /images/kernel/hash-1 value c9436464 6427e10f 423837e5 59898ef0 2c97b981
+ 51b2adf9 c1016ed4 6f424d85 dcc6c34c 46a20b9b ee7227e0 6a6b6320 ca5d35c1
+ fdtput -tx image.fit /images/kernel/hash-1 value 51b2adf9 c1016ed4 6f424d85 dcc6c34c 46a20b9b ee7227e0 6a6b6320 ca5d35c8
Now check it again::
$UOUT/tools/fit_check_sign -f image.fit -k am335x-boneblack-pubkey.dtb
- Verifying Hash Integrity ... sha1,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
+ Verifying Hash Integrity ... sha256,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
rsa_verify_with_keynode: RSA failed to verify: -13
-
Failed to verify required signature 'key-dev'
@@ -446,7 +446,7 @@
fdtput -p image.fit /configurations/conf-1/signature-1 value fred
$UOUT/tools/fit_check_sign -f image.fit -k am335x-boneblack-pubkey.dtb
Verifying Hash Integrity ... -
- sha1,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
+ sha256,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
rsa_verify_with_keynode: RSA failed to verify: -13
-
Failed to verify required signature 'key-dev'
@@ -528,7 +528,7 @@
U-Boot# bootm 82000000
## Loading kernel from FIT Image at 82000000 ...
Using 'conf-1' configuration
- Verifying Hash Integrity ... sha1,rsa2048:dev+ OK
+ Verifying Hash Integrity ... sha256,rsa2048:dev+ OK
Trying 'kernel' kernel subimage
Description: unavailable
Created: 2014-06-01 19:32:54 UTC
@@ -540,9 +540,9 @@
OS: Linux
Load Address: 0x80008000
Entry Point: 0x80008000
- Hash algo: sha1
- Hash value: c94364646427e10f423837e559898ef02c97b988
- Verifying Hash Integrity ... sha1+ OK
+ Hash algo: sha256
+ Hash value: 51b2adf9c1016ed46f424d85dcc6c34c46a20b9bee7227e06a6b6320ca5d35c1
+ Verifying Hash Integrity ... sha256+ OK
## Loading fdt from FIT Image at 82000000 ...
Using 'conf-1' configuration
Trying 'fdt-1' fdt subimage
@@ -553,9 +553,9 @@
Data Start: 0x8276e2ec
Data Size: 31547 Bytes = 30.8 KiB
Architecture: ARM
- Hash algo: sha1
- Hash value: cb09202f889d824f23b8e4404b781be5ad38a68d
- Verifying Hash Integrity ... sha1+ OK
+ Hash algo: sha256
+ Hash value: 807d5842a04132261ba092373bd40c78991bc7ce173d1175cd976ec37858e7cd
+ Verifying Hash Integrity ... sha256+ OK
Booting using the fdt blob at 0x8276e2ec
Uncompressing Kernel Image ... OK
Loading Device Tree to 8fff5000, end 8ffffb3a ... OK