Fix a text canonicalisation bug in CMS #5790
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Where a CMS detatched signature is used with text content the text goes through a canonicalisation process first prior to signing or verifying a signature. This process strips trailing space at the end of lines, converts line terminators to CRLF and removes additional trailing line terminators at the end of a file. A bug in the canonicalisation process meant that some characters, such as form-feed, were incorrectly treated as whitespace and removed. This is contrary to the specification (RFC5485). This fix could mean that detatched text data signed with an earlier version of OpenSSL 1.1.0 may fail to verify using the fixed version, or text data signed with a fixed OpenSSL may fail to verify with an earlier version of OpenSSL 1.1.0. A workaround is to only verify the canonicalised text data and use the "-binary" flag (for the "cms" command line application) or set the SMIME_BINARY/PKCS7_BINARY/CMS_BINARY flags (if using CMS_verify()).
mattcaswell
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See also #5791 for the 1.1.0 version |
t-j-h
approved these changes
Mar 29, 2018
levitte
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Mar 29, 2018
| at the end of a file. A bug in the canonicalisation process meant that | ||
| some characters, such as form-feed, were incorrectly treated as whitespace | ||
| and removed. This is contrary to the specification (RFC5485). This fix | ||
| could mean that detatched text data signed with an earlier version of |
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'detatched'... maybe a quick spell checking round?
levitte
approved these changes
Mar 29, 2018
|
Pushed (with spelling error fixed). Thanks. |
levitte
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Apr 3, 2018
Where a CMS detached signature is used with text content the text goes through a canonicalisation process first prior to signing or verifying a signature. This process strips trailing space at the end of lines, converts line terminators to CRLF and removes additional trailing line terminators at the end of a file. A bug in the canonicalisation process meant that some characters, such as form-feed, were incorrectly treated as whitespace and removed. This is contrary to the specification (RFC5485). This fix could mean that detached text data signed with an earlier version of OpenSSL 1.1.0 may fail to verify using the fixed version, or text data signed with a fixed OpenSSL may fail to verify with an earlier version of OpenSSL 1.1.0. A workaround is to only verify the canonicalised text data and use the "-binary" flag (for the "cms" command line application) or set the SMIME_BINARY/PKCS7_BINARY/CMS_BINARY flags (if using CMS_verify()). Reviewed-by: Tim Hudson <tjh@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from #5790)
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Where a CMS detatched signature is used with text content the text goes
through a canonicalisation process first prior to signing or verifying a
signature. This process strips trailing space at the end of lines, converts
line terminators to CRLF and removes additional trailing line terminators
at the end of a file. A bug in the canonicalisation process meant that
some characters, such as form-feed, were incorrectly treated as whitespace
and removed. This is contrary to the specification (RFC5485). This fix
could mean that detatched text data signed with an earlier version of
OpenSSL 1.1.0 may fail to verify using the fixed version, or text data
signed with a fixed OpenSSL may fail to verify with an earlier version of
OpenSSL 1.1.0. A workaround is to only verify the canonicalised text data
and use the "-binary" flag (for the "cms" command line application) or set
the SMIME_BINARY/PKCS7_BINARY/CMS_BINARY flags (if using CMS_verify()).
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