image: Add an option to do a full check of the FIT
Some strange modifications of the FIT can introduce security risks. Add an option to check it thoroughly, using libfdt's fdt_check_full() function. Enable this by default if signature verification is enabled. CVE-2021-27097 Signed-off-by: Simon Glass <sjg@chromium.org> Reported-by: Bruce Monroe <bruce.monroe@intel.com> Reported-by: Arie Haenel <arie.haenel@intel.com> Reported-by: Julien Lenoir <julien.lenoir@intel.com>
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@@ -63,6 +63,15 @@ config FIT_ENABLE_SHA512_SUPPORT
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SHA512 checksum is a 512-bit (64-byte) hash value used to check that
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the image contents have not been corrupted.
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config FIT_FULL_CHECK
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bool "Do a full check of the FIT before using it"
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default y
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help
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Enable this do a full check of the FIT to make sure it is valid. This
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helps to protect against carefully crafted FITs which take advantage
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of bugs or omissions in the code. This includes a bad structure,
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multiple root nodes and the like.
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config FIT_SIGNATURE
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bool "Enable signature verification of FIT uImages"
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depends on DM
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@@ -70,6 +79,7 @@ config FIT_SIGNATURE
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select RSA
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select RSA_VERIFY
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select IMAGE_SIGN_INFO
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select FIT_FULL_CHECK
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help
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This option enables signature verification of FIT uImages,
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using a hash signed and verified using RSA. If
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@@ -159,6 +169,15 @@ config SPL_FIT_PRINT
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help
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Support printing the content of the fitImage in a verbose manner in SPL.
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config SPL_FIT_FULL_CHECK
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bool "Do a full check of the FIT before using it"
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help
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Enable this do a full check of the FIT to make sure it is valid. This
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helps to protect against carefully crafted FITs which take advantage
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of bugs or omissions in the code. This includes a bad structure,
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multiple root nodes and the like.
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config SPL_FIT_SIGNATURE
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bool "Enable signature verification of FIT firmware within SPL"
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depends on SPL_DM
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@@ -168,6 +187,7 @@ config SPL_FIT_SIGNATURE
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select SPL_RSA
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select SPL_RSA_VERIFY
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select SPL_IMAGE_SIGN_INFO
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select SPL_FIT_FULL_CHECK
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config SPL_LOAD_FIT
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bool "Enable SPL loading U-Boot as a FIT (basic fitImage features)"
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