[PATCH v2 0/2] test/py: vboot: fix signature check on config node

[PATCH v2 0/2] test/py: vboot: fix signature check on config node

[Philippe Reynes]

The signature check of config node is broken when used on fit with padding.
We didn't see it before because this case is not covered by vboot test.

When check the signature for a config nde, u-boot uses all the properties
of the node referenced in the config node, except the property data. When
padding is used on fit, the property data is replaced by two properties:
data-offset and data-size, and u-boot uses those properties when checking
the signature. To fix this signature check, we simply ignore the properties
data-offset and data_size.

The first commit add some vboot tests that check signature on fit with
padding. The second commit fixes the signature check on config node for
fit with padding.

Philippe Reynes (2):
  test/py: vboot: add a test to check fit signature on fit with padding
  rsa: sig: fix config signature check for fit with padding

Changelog:
v2:
- fix spelling in commit message (thanks Simon)

 common/image-sig.c          |  2 +-
 test/py/tests/test_vboot.py | 42 ++++++++++++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 15 deletions(-)

-- 
2.7.4

[PATCH v2 1/2] test/py: vboot: add a test to check fit signature on fit with padding

[Philippe Reynes]

The pytest vboot does all his tests on fit without padding.
We add the same tests on fit with padding.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
---
 test/py/tests/test_vboot.py | 42 ++++++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 14 deletions(-)

Changelog:
v2:
- no change

diff --git a/test/py/tests/test_vboot.py b/test/py/tests/test_vboot.py
index 9c41ee5..32299be 100644
--- a/test/py/tests/test_vboot.py
+++ b/test/py/tests/test_vboot.py
@@ -94,7 +94,7 @@ def test_vboot(u_boot_console):
         util.run_and_log(cons, [mkimage, '-D', dtc_args, '-f',
                                 '%s%s' % (datadir, its), fit])
 
-    def sign_fit(sha_algo):
+    def sign_fit(sha_algo, options):
         """Sign the FIT
 
         Signs the FIT and writes the signature into it. It also writes the
@@ -103,10 +103,13 @@ def test_vboot(u_boot_console):
         Args:
             sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
                     use.
+            options: Options to provide to mkimage.
         """
+        args = [mkimage, '-F', '-k', tmpdir, '-K', dtb, '-r', fit]
+        if options:
+            args += options.split(' ')
         cons.log.action('%s: Sign images' % sha_algo)
-        util.run_and_log(cons, [mkimage, '-F', '-k', tmpdir, '-K', dtb,
-                                '-r', fit])
+        util.run_and_log(cons, args)
 
     def sign_fit_norequire(sha_algo):
         """Sign the FIT
@@ -142,7 +145,7 @@ def test_vboot(u_boot_console):
             handle.write(struct.pack(">I", size))
         return struct.unpack(">I", total_size)[0]
 
-    def test_with_algo(sha_algo, padding):
+    def test_with_algo(sha_algo, padding, sign_options):
         """Test verified boot with the given hash algorithm.
 
         This is the main part of the test code. The same procedure is followed
@@ -151,6 +154,9 @@ def test_vboot(u_boot_console):
         Args:
             sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
                     use.
+            padding: Either '' or '-pss', to select the padding to use for the
+                    rsa signature algorithm.
+            sign_options: Options to mkimage when signing a fit image.
         """
         # Compile our device tree files for kernel and U-Boot. These are
         # regenerated here since mkimage will modify them (by adding a
@@ -164,7 +170,7 @@ def test_vboot(u_boot_console):
         run_bootm(sha_algo, 'unsigned images', 'dev-', True)
 
         # Sign images with our dev keys
-        sign_fit(sha_algo)
+        sign_fit(sha_algo, sign_options)
         run_bootm(sha_algo, 'signed images', 'dev+', True)
 
         # Create a fresh .dtb without the public keys
@@ -175,7 +181,7 @@ def test_vboot(u_boot_console):
         run_bootm(sha_algo, 'unsigned config', '%s+ OK' % sha_algo, True)
 
         # Sign images with our dev keys
-        sign_fit(sha_algo)
+        sign_fit(sha_algo, sign_options)
         run_bootm(sha_algo, 'signed config', 'dev+', True)
 
         cons.log.action('%s: Check signed config on the host' % sha_algo)
@@ -211,7 +217,7 @@ def test_vboot(u_boot_console):
         util.run_and_log_expect_exception(cons, [fit_check_sign, '-f', fit,
                 '-k', dtb], 1, 'Failed to verify required signature')
 
-    def test_required_key(sha_algo, padding):
+    def test_required_key(sha_algo, padding, sign_options):
         """Test verified boot with the given hash algorithm.
 
         This function test if u-boot reject an image when a required
@@ -220,6 +226,9 @@ def test_vboot(u_boot_console):
         Args:
             sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
                     use.
+            padding: Either '' or '-pss', to select the padding to use for the
+                    rsa signature algorithm.
+            sign_options: Options to mkimage when signing a fit image.
         """
         # Compile our device tree files for kernel and U-Boot. These are
         # regenerated here since mkimage will modify them (by adding a
@@ -234,9 +243,9 @@ def test_vboot(u_boot_console):
         # This FIT should not be accepted by u-boot because the key prod is required
         cons.log.action('%s: Test FIT with configs images' % sha_algo)
         make_fit('sign-configs-%s%s-prod.its' % (sha_algo , padding))
-        sign_fit(sha_algo)
+        sign_fit(sha_algo, sign_options)
         make_fit('sign-configs-%s%s.its' % (sha_algo , padding))
-        sign_fit(sha_algo)
+        sign_fit(sha_algo, sign_options)
 
         run_bootm(sha_algo, 'signed configs', '', False)
 
@@ -282,11 +291,16 @@ def test_vboot(u_boot_console):
         # afterwards.
         old_dtb = cons.config.dtb
         cons.config.dtb = dtb
-        test_with_algo('sha1','')
-        test_with_algo('sha1','-pss')
-        test_with_algo('sha256','')
-        test_with_algo('sha256','-pss')
-        test_required_key('sha256','-pss')
+        test_with_algo('sha1','', None)
+        test_with_algo('sha1','', '-E -p 0x10000')
+        test_with_algo('sha1','-pss', None)
+        test_with_algo('sha1','-pss', '-E -p 0x10000')
+        test_with_algo('sha256','', None)
+        test_with_algo('sha256','', '-E -p 0x10000')
+        test_with_algo('sha256','-pss', None)
+        test_with_algo('sha256','-pss', '-E -p 0x10000')
+        test_required_key('sha256','-pss', None)
+        test_required_key('sha256','-pss', '-E -p 0x10000')
     finally:
         # Go back to the original U-Boot with the correct dtb.
         cons.config.dtb = old_dtb
-- 
2.7.4

[PATCH v2 1/2] test/py: vboot: add a test to check fit signature on fit with padding

[Tom Rini]

On Sat, Mar 28, 2020 at 05:06:04PM +0100, Philippe Reynes wrote:

> The pytest vboot does all his tests on fit without padding.
> We add the same tests on fit with padding.
> 
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
> ---
>  test/py/tests/test_vboot.py | 42 ++++++++++++++++++++++++++++--------------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> Changelog:
> v2:
> - no change

This and 2/2 need to be rebased on top of the current fixes that've been
done for the CVE we fixed in v2020.04 I believe, thanks and sorry!

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 659 bytes
Desc: not available
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20200428/1a5e6aa6/attachment.sig>

[PATCH v2 2/2] rsa: sig: fix config signature check for fit with padding

[Philippe Reynes]

The signature check on config node is broken on fit with padding.
To compute the signature for config node, U-Boot compute the
signature on all properties of requested node for this config,
except for the property "data". But, when padding is used for
binary in a fit, there isn't a property "data" but two properties:
"data-offset" and "data-size". So to fix the check of signature,
we also don't use the properties "data-offset" and "data-size"
when checking the signature on config node.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
---
 common/image-sig.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Changelog:
v2:
- fix spelling in commit message (thanks Simon)

diff --git a/common/image-sig.c b/common/image-sig.c
index 639a112..8a0ea28 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -362,7 +362,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 			 char **err_msgp)
 {
-	char * const exc_prop[] = {"data"};
+	char * const exc_prop[] = {"data", "data-size", "data-position"};
 	const char *prop, *end, *name;
 	struct image_sign_info info;
 	const uint32_t *strings;
-- 
2.7.4