Notable changes:
- libmagic is no longer used at all. All MIME type detection is
done through new Bro signatures, and there's no longer a means to get
verbose file type descriptions (e.g. "PNG image data, 1435 x 170").
The majority of the default file magic signatures are derived
from the default magic database of libmagic ~5.17.
- File magic signatures consist of two new constructs in the
signature rule parsing grammar: "file-magic" gives a regular
expression to match against, and "file-mime" gives the MIME type
string of content that matches the magic and an optional strength
value for the match.
- Modified signature/rule syntax for identifiers: they can no longer
start with a '-', which made for ambiguous syntax when doing negative
strength values in "file-mime". Also brought syntax for Bro script
identifiers in line with reality (they can't start with numbers or
include '-' at all).
- A new Built-In Function, "file_magic", can be used to get all
file magic matches and their corresponding strength against a given
chunk of data
- The second parameter of the "identify_data" Built-In Function
can no longer be used to get verbose file type descriptions, though it
can still be used to get the strongest matching file magic signature.
- The "file_transferred" event's "descr" parameter no longer
contains verbose file type descriptions.
- The BROMAGIC environment variable no longer changes any behavior
in Bro as magic databases are no longer used/installed.
- Reverted back to minimum requirement of CMake 2.6.3 from 2.8.0
(it's back to being the same requirement as the Bro v2.2 release).
The bump was to accomodate building libmagic as an external project,
which is no longer needed.
Addresses BIT-1143.
- Several places were just using old variable names or not loading
scripts correctly after they'd been renamed/moved.
- Revert/adjust a change in how HTTP file handles are generated that
broke partial content responses.
- Turn some libmagic builtin checks back on; seems some are actually
useful (e.g. text detection seems to be a builtin). The rule going
forward probably will be only to turn off a builtin if we confirm it
causes issues.
- Removed some tests that are redundant or not necessary anymore because
the generic file analysis tests cover them.
- A couple FTP tests still fail that I think need an actual solution via
script changes.
- It's derived from the magic database of libmagic 5.14, but with most
everything not related to mime types removed.
- The custom database is always used by default for mime detection, but
the more verbose file type detection will fall back on the default
libmagic installation's database. The result is: mime type strings
are now guaranteed to be consistent across platforms, but the verbose
file type descriptions are not.
- The custom database gets installed in $prefix/share/bro/magic, and
should even be extensible if files with new patterns are added inside
the directory.
- The search path for the mime magic database can be controlled via
BROMAGIC environment variable.
- Remove mime_desc field from ftp.log.
- Stop using the mime/file type canonifier with unit tests.
- libmagic >= 5.04 is now a requirement.
- FileAnalysis::Info is now just a record used for logging, the fa_file
record type is defined in init-bare.bro as the analogue to a
connection record.
- Starting to transfer policy hook triggers and analyzer results to
events.
Other misc:
- Remove HTTP::MD5 notice.
- Add "last_active" field to FileAnalysis::Info record.
- Replace "conn_uids", "conn_ids" fields in FileAnalysis::Info record
with just a "conns" fields containing full connection records.
- The http-methods unit test is failing now, but I think it will be
fixed once I change the file handle callback mechanism to use events
instead.
