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a1e452026e
The ASN.1 module in RFC 5280 appendix A.1 uses EXPLICIT TAGS whereas the
one in appendix A.2 uses IMPLICIT TAGS.
The kernel's simplified asn1_compiler.c always uses EXPLICIT TAGS, hence
definitions from appendix A.2 need to be annotated as IMPLICIT for the
compiler to generate RFC-compliant code.
In particular, GeneralName is defined in appendix A.2:
GeneralName ::= CHOICE {
otherName [0] OtherName,
...
dNSName [2] IA5String,
x400Address [3] ORAddress,
directoryName [4] Name,
...
}
Because appendix A.2 uses IMPLICIT TAGS, the IA5String tag (0x16) of a
dNSName is not rendered. Instead, the string directly succeeds the
[2] tag (0x82).
Likewise, the SEQUENCE tag (0x30) of an OtherName is not rendered.
Instead, only the constituents of the SEQUENCE are rendered: An OID tag
(0x06), a [0] tag (0xa0) and an ANY tag. That's three consecutive tags
instead of a single encompassing tag.
The situation is different for x400Address and directoryName choices:
They reference ORAddress and Name, which are defined in appendix A.1,
therefore use EXPLICIT TAGS.
The AKID ASN.1 module is missing several IMPLICIT annotations, hence
isn't RFC-compliant. In the unlikely event that an AKID contains other
elements beside a directoryName, users may see parse errors.
Add the missing annotations but do not tag this commit for stable as I
am not aware of any issue reports. Fixes are only eligible for stable
if they're "obviously correct" and with ASN.1 there's no such thing.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.