Having to check for header_len == len and a last byte of 0x80 is
actually unambiguous, but not obvious. Before we supported multi-byte
tags, a two-byte header was always {tag, 0x80}, but now a three-byte
header could be {tag1, tag2, 0x80}. But a 0x80 suffix could also be
{tag, 0x81, 0x80} for a 128-byte definite-length element.
This is unambiguous because header_len == len implies either zero length
or indefinite-length, and it is not possible to encode a definite length
of zero, in BER or DER, with a header that ends in 0x80. Still, rather
than go through all this, we can just report indefinite lengths to the
caller directly.
Update-Note: This is a breaking change to CBS_get_any_ber_asn1_element.
There is only one external caller of this function, and it should be
possible to fix them atomically with this change, so I haven't bothered
introducing another name, etc. (See cl/429632075 for the fix.)
Change-Id: Ic94dab562724fd0b388bc8d2a7a223f21a8da413
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/51625
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
One down, two more to go! As part of this, I've added it to doc.config,
revised the note at the top, and moved the sample i2d/d2i functions
here.
Bug: 426
Change-Id: I7bb9d56bf9ba58c921cfcf9626bf3647c6e5c7df
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/50107
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
There are a lot of d2i and i2d functions, and there will be even more
once asn1.h and x509.h are properly documented. We currently replicate
the text in each, but as a result a miss a few points:
- The i2d outp != NULL, *outp == NULL case isn't documented at all.
- We should call out what to do with *inp after d2i.
- Unlike our rewritten functions, object reuse is still quite rampant
with the asn1.h functions. I hope we can get rid of that but, until we
can, it would be nice to describe it in one place.
While I'm here, update a few references to the latest PKCS#1 RFC, and
try to align how we reference ASN.1 structures a bit. The d2i/i2d
functions say "ASN.1, DER-encoded RSA private key" while the CBS/CBB
functions say "DER-encoded RSAPrivateKey structure".
Bug: 426
Change-Id: I8d9a7b0aef3d6d9c8240136053c3b1704b09fd41
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/49906
Reviewed-by: Adam Langley <agl@google.com>
See also 8393de42498f8be75cf0353f5c9f906a43a748d2 from upstream and
CBS-2021-3712. But rather than do that, I've rewritten it with CBS, so
it's a bit clearer. The previous commit added tests.
Change-Id: Ie52e28f07b9bf805c8730eab7be5d40cb5d558b6
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/49008
Reviewed-by: Adam Langley <agl@google.com>
We fill in placeholder values of all zeros fairly often in TLS now,
as workarounds for messages being constructed in the wrong order.
draft-12 of ECH adds even more of these. Add a helper so we don't need
to interrupt an || chain with a memset.
Change-Id: Id4f9d988ee67598645a01637cc9515b475c1aec2
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/48909
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Bug: chromium:1221591
Change-Id: Ie8335e53b107ba019a1bde62c12f846802e056c5
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/48165
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
One of the comments in e56dfcf9f4 was worded awkwardly. Thanks to Zi Lin
for fixing this.
Change-Id: I7ee647716e0ee30145bdce5be35128058130e1ec
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/44764
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
BER permits lengths to be non-minimal. Previously this was not supported
at all. This change brings greater support, allowing non-minimal lengths
so long as they fit in a uint32_t.
Change-Id: I002ed2375c78fdb326e725eb1c23eca71ef9ba4a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/44684
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
We have several implementations of this internally, so consolidate them.
Chromium also has a copy in net/der/parse_values.cc which could call
into this.
(I'm also hoping we can make c2i_ASN1_INTEGER call this and
further tighten up crypto/asn1's parser, but I see Chromium still has an
allow_invalid_serial_numbers option, so perhaps not quite yet.)
Update-Note: This CL does not change behavior, but I'm leaving a note to
myself to make net/der/parse_values.cc call the new functions.
Change-Id: If2aae6574ba6a30e343e1308da6af543616156ec
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/44051
Reviewed-by: Adam Langley <agl@google.com>
David Benjamin
Peter Kasting
Adam Langley