Fix PKCS#7 verification of signature created with OpenSSL#10099
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haxtibal wants to merge 3 commits intowolfSSL:masterfrom
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Fix PKCS#7 verification of signature created with OpenSSL#10099haxtibal wants to merge 3 commits intowolfSSL:masterfrom
haxtibal wants to merge 3 commits intowolfSSL:masterfrom
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Can one of the admins verify this patch? |
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@haxtibal please resolve merge conflicts. For external contributions we need a signed contributor agreement. You can email support at wolfssl dot com to get that process started. Please reference the PR and tell us more about your project. Thanks, David Garske, wolfSSL |
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Intention is to verify PKCS#7 / CMS signatures produced by third party tools. The optional test is enabled by providing a comma separated list of external DER files that have previously been signed with a third party tool to configure --with-pkcs7-test-signed-data. Usage: openssl cms -sign -in <(echo -n "openssl cms interop test message") \ -signer certs/client-cert.pem -inkey certs/client-key.pem \ -md sha256 -nodetach -outform DER -out /tmp/cms.der openssl smime -sign -in <(echo -n "openssl smime interop test message") \ -signer certs/client-cert.pem -inkey certs/client-key.pem \ -md sha256 -binary -nodetach -outform DER -out /tmp/smime.der ./configure --enable-pkcs7 --enable-certext --enable-examples \ --with-pkcs7-test-signed-data=/tmp/cms.der,/tmp/smime.der make -j$(nproc) tests/unit.test -test_wc_PKCS7_VerifySignedData_interop
…rameters = NULL RFC 8017 hardcodes DER serialization samples of DigestInfo, where the parameter part is always NULL (05 00) for known hash algorithm [1]. This value does thus *not* depend on SignerInfo.digestAlgorithm.parameters. Starting with 75c3030 ("Add option for absent hash params in PKCS7"), wolfSSL wrongly assumed and implemented such a dependency. This non-conformance caused an interoperability bug with OpenSSL: A signature created with openssl cms could not be verified in WolfSSL. OpenSSL correctly leaves SignerInfo.digestAlgorithm.parameters absent and adds explicit NULL to DigestInfo. WolfSSL saw the absence and wrongly inferred DigestInfo would also have no explicit NULL - but it has - leading to size mismatch. Fix it by constructing the expected DigestInfo always with NULL (05 00). 4f21117 ("tests: Add PKCS#7 verification interoperability test") and 8d8170e (".github: Test PKCS7 interoperability for OpenSSL and GnuTLS") can be used to reproduce the bug and to demonstrate this commit fixes it. [1] https://www.rfc-editor.org/rfc/rfc8017#section-9.2
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@dgarske Thanks, done. Let me know if something's missing. |
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Description
RFC 8017 hardcodes DER serialization samples of DigestInfo, where the parameter part is always NULL (05 00) for known hash algorithm. This value does thus not depend on SignerInfo.digestAlgorithm.parameters. Starting with 75c3030, wolfSSL wrongly assumed and implemented such a dependency.
This non-conformance caused an interoperability bug with OpenSSL: A signature created with
openssl cmscould not be verified in WolfSSL. OpenSSL correctly leaves SignerInfo.digestAlgorithm.parameters absent and adds explicit NULL to DigestInfo. WolfSSL saw the absence and wrongly inferred DigestInfo would also have no explicit NULL - but it has - leading to size mismatch.Fix it by constructing the expected DigestInfo always with NULL (05 00).
The PR further adds an optional unit test to verify externally provided DER signature samples. A new CI job uses this to verify signatures created with OpenSSL and GnuTLS.
Testing
This was originally found, discussed and tested at Debian via a swugenerator autopkgtest. Pipelines in my wolfSSL fork run the newly added tests:
Checklist