Our CBB patterns do not make it safe to use a CBB after any operation
failed. Suppose one does:
int add_to_cbb(CBB *cbb) {
CBB child;
return CBB_add_u8(cbb, 1) &&
CBB_add_u8_length_prefixed(cbb, &child) &&
CBB_add_u8(&child, 2) &&
/* Flush |cbb| before |child| goes out of scoped. */
CBB_flush(cbb);
}
If one of the earlier operations fails, any attempt to use |cbb| (except
CBB_cleanup) would hit a memory error. Doing this would be a bug anyway,
since the CBB would be in an undefined state anyway (wrote only half my
object), but the memory error is bad manners.
Officially document that using a CBB after failure is illegal and, to
avoid the memory error, set a poison bit on the cbb_buffer_st to prevent
all future operations. In theory we could make failure +
CBB_discard_child work, but this is not very useful and would require a
more complex CBB pattern.
Change-Id: I4303ee1c326785849ce12b5f7aa8bbde6b95d2ec
Reviewed-on: https://boringssl-review.googlesource.com/8840
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
It was missing. Writing NewSessionTicket will need it.
Change-Id: I39de237894f2e8356bd6861da2b8a4d805dcd2d6
Reviewed-on: https://boringssl-review.googlesource.com/8439
Reviewed-by: Adam Langley <agl@google.com>
There is some messiness around saving and restoring the CBB, but this is
still significantly clearer.
Note that the BUF_MEM_grow line is gone in favor of a fixed CBB like the
other functions ported thus far. This line was never necessary as
init_buf is initialized to 16k and none of our key exchanges get that
large. (The largest one can get is DHE_RSA. Even so, it'd take a roughly
30k-bit DH group with a 30k-bit RSA key.)
Having such limits and tight assumptions on init_buf's initial size is
poor (but on par for the old code which usually just blindly assumed the
message would not get too large) and the size of the certificate chain
is much less obviously bounded, so those BUF_MEM_grows can't easily go.
My current plan is convert everything but those which legitimately need
BUF_MEM_grow to CBB, then atomically convert the rest, remove init_buf,
and switch everything to non-fixed CBBs. This will hopefully also
simplify async resumption. In the meantime, having a story for
resumption means the future atomic change is smaller and, more
importantly, relieves some complexity budget in the ServerKeyExchange
code for adding Curve25519.
Change-Id: I1de6af9856caaed353453d92a502ba461a938fbd
Reviewed-on: https://boringssl-review.googlesource.com/6770
Reviewed-by: Adam Langley <agl@google.com>
These will be needed when we start writing variable-length things to a
CBB.
Change-Id: Ie7b9b140f5f875b43adedc8203ce9d3f4068dfea
Reviewed-on: https://boringssl-review.googlesource.com/6764
Reviewed-by: Adam Langley <agl@google.com>
Rather than the length of the top-level CBB, which is kind of odd when ASN.1
length prefixes are not yet determined, return the number of bytes written to
the CBB so far. This can be computed without increasing the size of CBB at all.
Have offset and pending_*.
This means functions which take in a CBB as argument will not be sensitive to
whether the CBB is a top-level or child CBB. The extensions logic had to be
careful to only ever compare differences of lengths, which was awkward.
The reversal will also allow for the following pattern in the future, once
CBB_add_space is split into, say, CBB_reserve and CBB_did_write and we add a
CBB_data:
uint8_t *signature;
size_t signature_len = 0;
if (!CBB_add_asn1(out, &cert, CBB_ASN1_SEQUENCE) ||
/* Emit the TBSCertificate. */
!CBB_add_asn1(&cert, &tbs_cert, CBS_ASN1_SEQUENCE) ||
!CBB_add_tbs_cert_stuff(&tbs_cert, stuff) ||
!CBB_flush(&cert) ||
/* Feed it into md_ctx. */
!EVP_DigestSignInit(&md_ctx, NULL, EVP_sha256(), NULL, pkey) ||
!EVP_DigestSignUpdate(&md_ctx, CBB_data(&cert), CBB_len(&cert)) ||
/* Emit the signature algorithm. */
!CBB_add_asn1(&cert, &sig_alg, CBS_ASN1_SEQUENCE) ||
!CBB_add_sigalg_stuff(&sig_alg, other_stuff) ||
/* Emit the signature. */
!EVP_DigestSignFinal(&md_ctx, NULL, &signature_len) ||
!CBB_reserve(&cert, &signature, signature_len) ||
!EVP_DigestSignFinal(&md_ctx, signature, &signature_len) ||
!CBB_did_write(&cert, signature_len)) {
goto err;
}
(Were TBSCertificate not the first field, we'd still have to sample
CBB_len(&cert), but at least that's reasonable straight-forward. The
alternative would be if CBB_data and CBB_len somehow worked on
recently-invalidated CBBs, but that would go wrong once the invalidated CBB's
parent flushed and possibly shifts everything.)
And similar for signing ServerKeyExchange.
Change-Id: I7761e492ae472d7632875b5666b6088970261b14
Reviewed-on: https://boringssl-review.googlesource.com/6681
Reviewed-by: Adam Langley <agl@google.com>
People expect to do:
CBB foo;
if (!CBB_init(&foo, 100) ||
…
…) {
CBB_cleanup(&foo);
return 0;
}
However, currently, if the allocation of |initial_capacity| fails in
|CBB_init| then |CBB_cleanup| will operate on uninitialised values. This
change makes the above pattern safe.
Change-Id: I3e002fda8f0a3ac18650b504e7e84a842d4165ca
Reviewed-on: https://boringssl-review.googlesource.com/6495
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
Start converting the ones we can right now. Some of the messier ones
resize init_buf rather than assume the initial size is sufficient, so
those will probably wait until init_buf is gone and the handshake's
undergone some more invasive surgery. The async ones will also require
some thought. But some can be incrementally converted now.
BUG=468889
Change-Id: I0bc22e4dca37d9d671a488c42eba864c51933638
Reviewed-on: https://boringssl-review.googlesource.com/6190
Reviewed-by: Adam Langley <alangley@gmail.com>
Also add an assert to that effect.
Change-Id: I1bd0571e3889f1cba968fd99041121ac42ee9e89
Reviewed-on: https://boringssl-review.googlesource.com/5990
Reviewed-by: Adam Langley <agl@google.com>
It switched from CBB_remaining to CBB_len partway through review, but
the semantics are still CBB_remaining. Using CBB_len allows the
len_before/len_after logic to continue working even if, in the future,
handshake messages are built on a non-fixed CBB.
Change-Id: Id466bb341a14dbbafcdb26e4c940a04181f2787d
Reviewed-on: https://boringssl-review.googlesource.com/5371
Reviewed-by: Adam Langley <agl@google.com>
One tedious thing about using CBB is that you can't safely CBB_cleanup
until CBB_init is successful, which breaks the general 'goto err' style
of cleanup. This makes it possible:
CBB_zero ~ EVP_MD_CTX_init
CBB_init ~ EVP_DigestInit
CBB_cleanup ~ EVP_MD_CTX_cleanup
Change-Id: I085ecc4405715368886dc4de02285a47e7fc4c52
Reviewed-on: https://boringssl-review.googlesource.com/5267
Reviewed-by: Adam Langley <agl@google.com>
Rather than four massive functions that handle every extension,
organise the code by extension with four smaller functions for each.
Change-Id: I876b31dacb05aca9884ed3ae7c48462e6ffe3b49
Reviewed-on: https://boringssl-review.googlesource.com/5142
Reviewed-by: Adam Langley <agl@google.com>
First batch of the alphabet.
Change-Id: If4e60f4fbb69e04eb4b70aa1b2240e329251bfa5
Reviewed-on: https://boringssl-review.googlesource.com/4514
Reviewed-by: Adam Langley <agl@google.com>
Tag number 31 is a long form tag that requires multiple octets. It
cannot be handled by adding a single uint8. Changed CBB_add_asn1()
to return 0 when it is passed in the extension for tag 31.
Change-Id: Ia33936d4f174d1a7176eb11da0b5c7370efb9416
CBB_init_fixed() should not call free because it can lead to use after
free or double free bugs. The caller should be responsible for
creating and destroying the buffer.
In the current code, ssl3_get_v2_client_hello() may free s->init_buf->data
via CBB_init_fixed(). It can also be freed via SSL_free(s) since
ssl3_get_v2_client_hello() doesn't set it to NULL and CBB_init_fixed()
can't set the caller's pointer to NULL.
Change-Id: Ia05a67ae25af7eb4fb04f08f20d50d912b41e38b
Including string.h in base.h causes any file that includes a BoringSSL
header to include string.h. Generally this wouldn't be a problem,
although string.h might slow down the compile if it wasn't otherwise
needed. However, it also causes problems for ipsec-tools in Android
because OpenSSL didn't have this behaviour.
This change removes string.h from base.h and, instead, adds it to each
.c file that requires it.
Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37
Reviewed-on: https://boringssl-review.googlesource.com/3200
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
Companion to CBS_get_asn1_uint64. Also add tests for both the parsing and the
serializing.
Change-Id: Ic5e9a0089c88b300f874712d0e9964cb35a8c40b
Reviewed-on: https://boringssl-review.googlesource.com/1999
Reviewed-by: Adam Langley <agl@google.com>
ssl23_get_client_hello has lots of remnants of SSLv2 support and remnants of an
even older SSL_OP_NON_EXPORT_FIRST option (see upstream's
d92f0bb6e9ed94ac0c3aa0c939f2565f2ed95935) which complicates the logic.
Split it into three states and move V2ClientHello parsing into its own
function. Port it to CBS and CBB to give bounds checks on the V2ClientHello
parse.
This fixes a minor bug where, if the SSL_accept call in ssl23_get_client_hello
failed, cb would not be NULL'd and SSL_CB_ACCEPT_LOOP would get reported an
extra time.
It also unbreaks the invariant between s->packet, s->packet_length,
s->s3->rbuf.buf, and s->s3->rbuf.offset at the point the switch, although this
was of no consequence because the first ssl3_read_n call passes extend = 0
which resets s->packet and s->packet_length.
It also makes us tolerant to major version bumps in the ClientHello. Add tests
for TLS tolerance of both minor and major version bumps as well as the HTTP
request error codes.
Change-Id: I948337f4dc483f4ebe1742d3eba53b045b260257
Reviewed-on: https://boringssl-review.googlesource.com/1455
Reviewed-by: Adam Langley <agl@google.com>
This function serialises a PKCS#7 structure containing a number of
certificates.
Change-Id: Iaf15887e1060d5d201d5a3dd3dca8d51105ee6d6
Reviewed-on: https://boringssl-review.googlesource.com/1431
Reviewed-by: Adam Langley <agl@google.com>
When shifting data because extra ASN.1 length bytes were needed, the
data was moved from the start of the ASN.1 length, not the start of the
ASN.1 data.
Change-Id: Ib13d5e4e878774df2af0505c0297eff6cf781728
Reviewed-on: https://boringssl-review.googlesource.com/1430
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
