Don't return invalid versions in version_from_wire.
This is in preparation for using the supported_versions extension to
experiment with draft TLS 1.3 versions, since we don't wish to restore
the fallback. With versions begin opaque values, we will want
version_from_wire to reject unknown values, not attempt to preserve
order in some way.
This means ClientHello.version processing needs to be separate code.
That's just written out fully in negotiate_version now. It also means
SSL_set_{min,max}_version will notice invalid inputs which aligns us
better with upstream's versions of those APIs.
This CL doesn't replace ssl->version with an internal-representation
version, though follow work should do it once a couple of changes land
in consumers.
BUG=90
Change-Id: Id2f5e1fa72847c823ee7f082e9e69f55e51ce9da
Reviewed-on: https://boringssl-review.googlesource.com/11122
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/internal.h b/ssl/internal.h
index bdb392c..eff5672 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1090,14 +1090,10 @@
uint16_t min_version;
/* max_version is the maximum implemented version. */
uint16_t max_version;
- /* version_from_wire maps |wire_version| to a protocol version. For
- * SSLv3/TLS, the version is returned as-is. For DTLS, the corresponding TLS
- * version is used. Note that this mapping is not injective but preserves
- * comparisons.
- *
- * TODO(davidben): To normalize some DTLS-specific code, move away from using
- * the wire version except at API boundaries. */
- uint16_t (*version_from_wire)(uint16_t wire_version);
+ /* version_from_wire maps |wire_version| to a protocol version. On success, it
+ * sets |*out_version| to the result and returns one. If the version is
+ * unknown, it returns zero. */
+ int (*version_from_wire)(uint16_t *out_version, uint16_t wire_version);
/* version_to_wire maps |version| to the wire representation. It is an error
* to call it with an invalid version. */
uint16_t (*version_to_wire)(uint16_t version);
