[U-Boot] [PATCH] common, image-sig: [BUG?] if no valid signature node found, do not boot signed FIT image
fit_image_verify_required_sigs() must return != 0, on error.
When fit_image_verify_required_sigs() does not find a signature node, it returns 0, which leads in booting a signed FIT image.
Fix this!
Signed-off-by: Heiko Schocher hs@denx.de ---
Found on an imx28 based board, with key dtb appended to u-boot.bin.
Booting signed FIT image without an valid key dtb appended to u-boot.bin shows:
Using FEC1 device TFTP from server 192.168.1.1; our IP address is 192.168.20.103 Filename '/tftpboot/xxx/20170509/signed.fit'. Load address: 0x42000000 Loading: ################################################################# [...] ########### 3.3 MiB/s done Bytes transferred = 12560801 (bfa9a1 hex) Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: Linux kernel Created: 2017-06-08 9:10:14 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x420000c0 Data Size: 4078928 Bytes = 3.9 MiB Architecture: ARM OS: Linux Load Address: 0x40008000 Entry Point: 0x40008000 Hash algo: sha256 Hash value: 6d1dce3e08133ac4d34c0e07ce266f5cffc6f5a2713619c9ff76ca4b04df4a5b Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Using 'conf@1' configuration Trying 'ramdisk@1' ramdisk subimage Description: miro ramdisk Created: 2017-06-08 9:10:14 UTC Type: RAMDisk Image Compression: gzip compressed Data Start: 0x423e92b0 Data Size: 8457506 Bytes = 8.1 MiB Architecture: ARM OS: Linux Load Address: 0x00000000 Entry Point: 0x00000000 Hash algo: sha256 Hash value: da60884efa4373e7003940a56271c326f159ff74356ded28d8ebe108af807cda Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Using 'conf@1' configuration Trying 'fdt@1' fdt subimage Description: miro device tree Created: 2017-06-08 9:10:14 UTC Type: Flat Device Tree Compression: uncompressed Data Start: 0x423e41b4 Data Size: 19852 Bytes = 19.4 KiB Architecture: ARM Hash algo: sha256 Hash value: 9b39c3ab6227bb8f0bcebc0bb64439248a6670dfe873bb1c6536764e0dc1623c Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Booting using the fdt blob at 0x423e41b4 Loading Kernel Image ... OK Loading Ramdisk to 47303000, end 47b13d22 ... OK Loading Device Tree to 472fb000, end 47302d8b ... OK
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.11.0 (hs@hercules.denx.de) (gcc version 6.2.0 (GCC) ) #1 Tue May 16 07:31:30 CEST 2017 [...]
And linux boots ... which is bad, as we have no valid key appended to u-boot.bin ...
With this patch it shows:
Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: Linux kernel Created: 2017-06-08 9:34:28 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x420000c0 Data Size: 4078928 Bytes = 3.9 MiB Architecture: ARM OS: Linux Load Address: 0x40008000 Entry Point: 0x40008000 Hash algo: sha256 Hash value: 6d1dce3e08133ac4d34c0e07ce266f5cffc6f5a2713619c9ff76ca4b04df4a5b Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:34:29 UTC Verifying Hash Integrity ... error! Unable to verify required signature for '' hash node in 'kernel@1' image node Bad Data Hash ERROR: can't get kernel image! =>
common/image-sig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/image-sig.c b/common/image-sig.c index 455f2b9..646fb08 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -265,7 +265,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, if (sig_node < 0) { debug("%s: No signature node found: %s\n", __func__, fdt_strerror(sig_node)); - return 0; + return 1; }
fdt_for_each_subnode(noffset, sig_blob, sig_node) {
On Thu, Jun 08, 2017 at 11:52:45AM +0200, Heiko Schocher wrote:
fit_image_verify_required_sigs() must return != 0, on error.
When fit_image_verify_required_sigs() does not find a signature node, it returns 0, which leads in booting a signed FIT image.
Fix this!
Signed-off-by: Heiko Schocher hs@denx.de
Good catch. Did you confirm that the sandbox tests still work? And can you construct a new test for this case? Thanks!
Hi Heiko,
On 8 June 2017 at 03:52, Heiko Schocher hs@denx.de wrote:
fit_image_verify_required_sigs() must return != 0, on error.
When fit_image_verify_required_sigs() does not find a signature node, it returns 0, which leads in booting a signed FIT image.
Fix this!
Signed-off-by: Heiko Schocher hs@denx.de
Found on an imx28 based board, with key dtb appended to u-boot.bin.
Booting signed FIT image without an valid key dtb appended to u-boot.bin shows:
Using FEC1 device TFTP from server 192.168.1.1; our IP address is 192.168.20.103 Filename '/tftpboot/xxx/20170509/signed.fit'. Load address: 0x42000000 Loading: ################################################################# [...] ########### 3.3 MiB/s done Bytes transferred = 12560801 (bfa9a1 hex) Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: Linux kernel Created: 2017-06-08 9:10:14 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x420000c0 Data Size: 4078928 Bytes = 3.9 MiB Architecture: ARM OS: Linux Load Address: 0x40008000 Entry Point: 0x40008000 Hash algo: sha256 Hash value: 6d1dce3e08133ac4d34c0e07ce266f5cffc6f5a2713619c9ff76ca4b04df4a5b Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Using 'conf@1' configuration Trying 'ramdisk@1' ramdisk subimage Description: miro ramdisk Created: 2017-06-08 9:10:14 UTC Type: RAMDisk Image Compression: gzip compressed Data Start: 0x423e92b0 Data Size: 8457506 Bytes = 8.1 MiB Architecture: ARM OS: Linux Load Address: 0x00000000 Entry Point: 0x00000000 Hash algo: sha256 Hash value: da60884efa4373e7003940a56271c326f159ff74356ded28d8ebe108af807cda Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Using 'conf@1' configuration Trying 'fdt@1' fdt subimage Description: miro device tree Created: 2017-06-08 9:10:14 UTC Type: Flat Device Tree Compression: uncompressed Data Start: 0x423e41b4 Data Size: 19852 Bytes = 19.4 KiB Architecture: ARM Hash algo: sha256 Hash value: 9b39c3ab6227bb8f0bcebc0bb64439248a6670dfe873bb1c6536764e0dc1623c Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:10:15 UTC Verifying Hash Integrity ... sha256+ sha256,rsa4096:dev- OK ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Booting using the fdt blob at 0x423e41b4 Loading Kernel Image ... OK Loading Ramdisk to 47303000, end 47b13d22 ... OK Loading Device Tree to 472fb000, end 47302d8b ... OK
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.11.0 (hs@hercules.denx.de) (gcc version 6.2.0 (GCC) ) #1 Tue May 16 07:31:30 CEST 2017 [...]
And linux boots ... which is bad, as we have no valid key appended to u-boot.bin ...
With this patch it shows:
Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: Linux kernel Created: 2017-06-08 9:34:28 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x420000c0 Data Size: 4078928 Bytes = 3.9 MiB Architecture: ARM OS: Linux Load Address: 0x40008000 Entry Point: 0x40008000 Hash algo: sha256 Hash value: 6d1dce3e08133ac4d34c0e07ce266f5cffc6f5a2713619c9ff76ca4b04df4a5b Sign algo: sha256,rsa4096:dev Sign value: xxx Timestamp: 2017-06-08 9:34:29 UTC Verifying Hash Integrity ... error! Unable to verify required signature for '' hash node in 'kernel@1' image node Bad Data Hash ERROR: can't get kernel image! =>
common/image-sig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/image-sig.c b/common/image-sig.c index 455f2b9..646fb08 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -265,7 +265,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, if (sig_node < 0) { debug("%s: No signature node found: %s\n", __func__, fdt_strerror(sig_node));
return 0;
return 1;
Thanks for finding/fixing this! I suggest returning -EPERM.
Also note that using image-based security is somewhat insecure since people can mix and match them. Configuration signing is preferred if you can do it.
As Tom said, can you add a test please?
} fdt_for_each_subnode(noffset, sig_blob, sig_node) {-- 2.7.4
Regards, Simon
Hello Simon,
Am 09.06.2017 um 05:05 schrieb Simon Glass:
Hi Heiko,
On 8 June 2017 at 03:52, Heiko Schocher hs@denx.de wrote:
fit_image_verify_required_sigs() must return != 0, on error.
When fit_image_verify_required_sigs() does not find a signature node, it returns 0, which leads in booting a signed FIT image.
Fix this!
Signed-off-by: Heiko Schocher hs@denx.de
Found on an imx28 based board, with key dtb appended to u-boot.bin.
Booting signed FIT image without an valid key dtb appended to u-boot.bin shows:
[...]
common/image-sig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/image-sig.c b/common/image-sig.c index 455f2b9..646fb08 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -265,7 +265,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, if (sig_node < 0) { debug("%s: No signature node found: %s\n", __func__, fdt_strerror(sig_node));
return 0;
return 1;Thanks for finding/fixing this! I suggest returning -EPERM.
Ok, changed.
Also note that using image-based security is somewhat insecure since people can mix and match them. Configuration signing is preferred if you can do it.
I do this, here my configurations node from the its file:
configurations { default = "conf@1"; conf@1 { description = "board config 1"; kernel = "kernel@1"; fdt = "fdt@1"; ramdisk = "ramdisk@1"; signature@1 { algo = "sha256,rsa4096"; key-name-hint = "dev"; }; }; };
As Tom said, can you add a test please?
Hmm... tried with current U-Boot, the steps described in
test/image/test-fit.py
# make O=sandbox sandbox_config # make O=sandbox # ./test/image/test-fit.py -u sandbox/u-boot
and get:
pollux:u-boot hs [master] $ ./test/image/test-fit.py -u sandbox/u-boot FIT Tests ========= Warning (unit_address_vs_reg): Node /reset@0 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/kernel@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/kernel@2 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/fdt@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/fdt@1/signature@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/ramdisk@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/ramdisk@2 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /configurations/conf@1 has a unit name, but no reg property Kernel load
U-Boot 2017.07-rc1-00997-gad701b1 (Jun 09 2017 - 06:18:46 +0200)
DRAM: 128 MiB MMC: Using default environment
In: serial Out: serial Err: serial SCSI: Net: No ethernet found. IDE: Bus 0: not available 18474 bytes read in 0 ms ## Loading kernel from FIT Image at 00001000 ... Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: unavailable Created: 2017-06-09 4:19:13 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x000010c8 Data Size: 3491 Bytes = 3.4 KiB Architecture: Sandbox OS: Linux Load Address: 0x00040000 Entry Point: 0x00000008 Verifying Hash Integrity ... OK ## Loading fdt from FIT Image at 00001000 ... Using 'conf@1' configuration Trying 'fdt@1' fdt subimage Description: snow Created: 2017-06-09 4:19:13 UTC Type: Flat Device Tree Compression: uncompressed Data Start: 0x00002d30 Data Size: 193 Bytes = 193 Bytes Architecture: Sandbox Sign algo: sha1,rsa2048:dev Sign value: unavailable Timestamp: unavailable Verifying Hash Integrity ... sha1,rsa2048:dev- OK Booting using the fdt blob at 0x002d30 Loading Kernel Image ... OK 3491 bytes written in 0 ms 193 bytes written in 0 ms 4591 bytes written in 0 ms 3491 bytes written in 0 ms 4591 bytes written in 0 ms
Expected '%s' but not found in output:
U-Boot 2017.07-rc1-00997-gad701b1 (Jun 09 2017 - 06:18:46 +0200)
DRAM: 128 MiB MMC: Using default environment
In: serial Out: serial Err: serial SCSI: Net: No ethernet found. IDE: Bus 0: not available 18474 bytes read in 0 ms ## Loading kernel from FIT Image at 00001000 ... Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: unavailable Created: 2017-06-09 4:19:13 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x000010c8 Data Size: 3491 Bytes = 3.4 KiB Architecture: Sandbox OS: Linux Load Address: 0x00040000 Entry Point: 0x00000008 Verifying Hash Integrity ... OK ## Loading fdt from FIT Image at 00001000 ... Using 'conf@1' configuration Trying 'fdt@1' fdt subimage Description: snow Created: 2017-06-09 4:19:13 UTC Type: Flat Device Tree Compression: uncompressed Data Start: 0x00002d30 Data Size: 193 Bytes = 193 Bytes Architecture: Sandbox Sign algo: sha1,rsa2048:dev Sign value: unavailable Timestamp: unavailable Verifying Hash Integrity ... sha1,rsa2048:dev- OK Booting using the fdt blob at 0x002d30 Loading Kernel Image ... OK 3491 bytes written in 0 ms 193 bytes written in 0 ms 4591 bytes written in 0 ms 3491 bytes written in 0 ms 4591 bytes written in 0 ms
Traceback (most recent call last): File "./test/image/test-fit.py", line 481, in <module> run_tests() File "./test/image/test-fit.py", line 470, in run_tests run_fit_test(mkimage, options.u_boot) File "./test/image/test-fit.py", line 395, in run_fit_test line = find_matching(stdout, 'Booting using the FDT blob at ') File "./test/image/test-fit.py", line 286, in find_matching raise ValueError('Test aborted') ValueError: Test aborted
:-(
With my patch: pollux:u-boot hs [master] $ git diff diff --git a/common/image-sig.c b/common/image-sig.c index 455f2b9..e5ba85a 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -265,7 +265,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, if (sig_node < 0) { debug("%s: No signature node found: %s\n", __func__, fdt_strerror(sig_node)); - return 0; + return -EPERM; }
fdt_for_each_subnode(noffset, sig_blob, sig_node) { pollux:u-boot hs [master] $ ./test/image/test-fit.py -u sandbox/u-boot FIT Tests ========= Warning (unit_address_vs_reg): Node /reset@0 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/kernel@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/kernel@2 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/fdt@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/fdt@1/signature@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/ramdisk@1 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /images/ramdisk@2 has a unit name, but no reg property Warning (unit_address_vs_reg): Node /configurations/conf@1 has a unit name, but no reg property Kernel load
U-Boot 2017.07-rc1-00997-gad701b1-dirty (Jun 09 2017 - 06:21:36 +0200)
DRAM: 128 MiB MMC: Using default environment
In: serial Out: serial Err: serial SCSI: Net: No ethernet found. IDE: Bus 0: not available 18474 bytes read in 1 ms (17.6 MiB/s) ## Loading kernel from FIT Image at 00001000 ... Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: unavailable Created: 2017-06-09 4:22:07 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x000010c8 Data Size: 3491 Bytes = 3.4 KiB Architecture: Sandbox OS: Linux Load Address: 0x00040000 Entry Point: 0x00000008 Verifying Hash Integrity ... error! Unable to verify required signature for '' hash node in 'kernel@1' image node Bad Data Hash ERROR: can't get kernel image! XIP Invalid Image ... OK 3491 bytes written in 0 ms 193 bytes written in 0 ms 4591 bytes written in 0 ms 3491 bytes written in 0 ms 4591 bytes written in 0 ms
U-Boot 2017.07-rc1-00997-gad701b1-dirty (Jun 09 2017 - 06:21:36 +0200)
DRAM: 128 MiB MMC: Using default environment
In: serial Out: serial Err: serial SCSI: Net: No ethernet found. IDE: Bus 0: not available 18474 bytes read in 1 ms (17.6 MiB/s) ## Loading kernel from FIT Image at 00001000 ... Using 'conf@1' configuration Verifying Hash Integrity ... OK Trying 'kernel@1' kernel subimage Description: unavailable Created: 2017-06-09 4:22:07 UTC Type: Kernel Image Compression: uncompressed Data Start: 0x000010c8 Data Size: 3491 Bytes = 3.4 KiB Architecture: Sandbox OS: Linux Load Address: 0x00040000 Entry Point: 0x00000008 Verifying Hash Integrity ... error! Unable to verify required signature for '' hash node in 'kernel@1' image node Bad Data Hash ERROR: can't get kernel image! XIP Invalid Image ... OK 3491 bytes written in 0 ms 193 bytes written in 0 ms 4591 bytes written in 0 ms 3491 bytes written in 0 ms 4591 bytes written in 0 ms
Traceback (most recent call last): File "./test/image/test-fit.py", line 481, in <module> run_tests() File "./test/image/test-fit.py", line 470, in run_tests run_fit_test(mkimage, options.u_boot) File "./test/image/test-fit.py", line 388, in run_fit_test fail('Kernel not loaded', stdout) File "./test/image/test-fit.py", line 306, in fail raise ValueError("Test '%s' failed: %s" % (test_name, msg)) ValueError: Test 'Kernel load' failed: Kernel not loaded pollux:u-boot hs [master] $
Can you verify this?
Thanks!
bye, Heiko
} fdt_for_each_subnode(noffset, sig_blob, sig_node) {-- 2.7.4
Regards, Simon
Hi Heiko,
On 8 June 2017 at 22:52, Heiko Schocher hs@denx.de wrote:
Hello Simon,
Am 09.06.2017 um 05:05 schrieb Simon Glass:
Hi Heiko,
On 8 June 2017 at 03:52, Heiko Schocher hs@denx.de wrote:
fit_image_verify_required_sigs() must return != 0, on error.
When fit_image_verify_required_sigs() does not find a signature node, it returns 0, which leads in booting a signed FIT image.
Fix this!
Signed-off-by: Heiko Schocher hs@denx.de
Found on an imx28 based board, with key dtb appended to u-boot.bin.
Booting signed FIT image without an valid key dtb appended to u-boot.bin shows:
[...]
common/image-sig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/image-sig.c b/common/image-sig.c index 455f2b9..646fb08 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -265,7 +265,7 @@ int fit_image_verify_required_sigs(const void *fit, int image_noffset, if (sig_node < 0) { debug("%s: No signature node found: %s\n", __func__, fdt_strerror(sig_node));
return 0;
return 1;Thanks for finding/fixing this! I suggest returning -EPERM.
Ok, changed.
Also note that using image-based security is somewhat insecure since people can mix and match them. Configuration signing is preferred if you can do it.
I do this, here my configurations node from the its file:
configurations { default = "conf@1"; conf@1 { description = "board config 1"; kernel = "kernel@1"; fdt = "fdt@1"; ramdisk = "ramdisk@1"; signature@1 { algo = "sha256,rsa4096"; key-name-hint = "dev"; }; }; };As Tom said, can you add a test please?
Hmm... tried with current U-Boot, the steps described in
test/image/test-fit.py
# make O=sandbox sandbox_config # make O=sandbox # ./test/image/test-fit.py -u sandbox/u-boot
and get:
pollux:u-boot hs [master] $ ./test/image/test-fit.py -u sandbox/u-boot FIT Tests =========
[...]
Traceback (most recent call last): File "./test/image/test-fit.py", line 481, in <module> run_tests() File "./test/image/test-fit.py", line 470, in run_tests run_fit_test(mkimage, options.u_boot) File "./test/image/test-fit.py", line 388, in run_fit_test fail('Kernel not loaded', stdout) File "./test/image/test-fit.py", line 306, in fail raise ValueError("Test '%s' failed: %s" % (test_name, msg)) ValueError: Test 'Kernel load' failed: Kernel not loaded pollux:u-boot hs [master] $
Can you verify this?
Yes I see that too. I bisected it and sent a patch.
Regards, Simon
Thanks!
bye, Heiko
} fdt_for_each_subnode(noffset, sig_blob, sig_node) {-- 2.7.4
Regards, Simon
-- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
participants (3)
-
Heiko Schocher -
Simon Glass -
Tom Rini