tree dc290e78d478f2752d15f4e613ea87e0f5fa5f71
parent 6d70353ca8bc55b54f19af00fb7d9b074208ff1c
author David Benjamin <davidben@google.com> 1598899669 -0400
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1600370297 +0000

Require non-NULL store in X509_STORE_CTX_init.

X509_STORE_CTX_init is documented upstream to allow a NULL store and has
logic to account for it. However, attempting to use such an
X509_STORE_CTX crashes in X509_verify_cert due to the
additional_untrusted logic we added.

Moreover, before that change, it still crashes because
X509_STORE_CTX_get1_issuer (the default get_issuer hook) assumes
ctx->ctx (the store) is non-null. This was also true in upstream but
later fixed in https://github.com/openssl/openssl/pull/6001. However,
without a store, there is no trust anchor, so this is not very useful.
Reject NULL stores in X509_STORE_CTX_init and remove the logic allowing
for a NULL one.

Thanks to Danny Halawi for catching this.

Update-Note: X509_STORE_CTX_init will now fail when the store is NULL,
rather than report success, only to crash later in X509_verify_cert.
Breakage should thus be limited to code which was passing in a NULL
store but never used the resulting X509_STORE_CTX.

Change-Id: I9db0289612cc245a8d62d6fa647d6b56b2daabda
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/42728
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>