zeek/scripts/base/protocols/http/file-hash.bro
Robin Sommer da90976170 Merge remote-tracking branch 'origin/topic/matthias/opaque'
* origin/topic/matthias/opaque:
  Add new unit test for opaque serialization.
  Migrate entropy testing to opaque.
  C++ify RandTest.*
  Fix a hard-to-spot bug.
  Use more descriptive error message.
  Fix the fix :-/.
  Fix initialization of hash values.
  Be clearer about delegation.
  Implement serialization of opaque types.
  Update hash BiF documentation.
  Migrate free SHA* functions to SHA*Val::digest().
  Add missing type name that caused failing tests.
  Update base scripts and unit tests.
  Simplify hash function BiFs.
  Add support for opaque hash values.
  Adapt BiF & Bro parser to handle opaque types.
  More lexer/parser work.
  Implement equivalence relation for opaque types.
  Support basic serialization of opaque.
  Add opaque type to lexer, parser, and BroType.

Closes #925

Conflicts:
	aux/broccoli
2012-12-20 16:30:22 -08:00

92 lines
2.7 KiB
Text

##! Calculate hashes for HTTP body transfers.
@load ./file-ident
module HTTP;
export {
redef enum Notice::Type += {
## Indicates that an MD5 sum was calculated for an HTTP response body.
MD5,
};
redef record Info += {
## MD5 sum for a file transferred over HTTP calculated from the
## response body.
md5: string &log &optional;
## This value can be set per-transfer to determine per request
## if a file should have an MD5 sum generated. It must be
## set to T at the time of or before the first chunk of body data.
calc_md5: bool &default=F;
## Indicates if an MD5 sum is being calculated for the current
## request/response pair.
md5_handle: opaque of md5 &optional;
};
## Generate MD5 sums for these filetypes.
const generate_md5 = /application\/x-dosexec/ # Windows and DOS executables
| /application\/x-executable/ # *NIX executable binary
&redef;
}
## Initialize and calculate the hash.
event http_entity_data(c: connection, is_orig: bool, length: count, data: string) &priority=5
{
if ( is_orig || ! c?$http ) return;
if ( c$http$first_chunk )
{
if ( c$http$calc_md5 ||
(c$http?$mime_type && generate_md5 in c$http$mime_type) )
{
c$http$md5_handle = md5_hash_init();
}
}
if ( c$http?$md5_handle )
md5_hash_update(c$http$md5_handle, data);
}
## In the event of a content gap during a file transfer, detect the state for
## the MD5 sum calculation and stop calculating the MD5 since it would be
## incorrect anyway.
event content_gap(c: connection, is_orig: bool, seq: count, length: count) &priority=5
{
if ( is_orig || ! c?$http || ! c$http?$md5_handle ) return;
set_state(c, F, is_orig);
md5_hash_finish(c$http$md5_handle); # Ignore return value.
delete c$http$md5_handle;
}
## When the file finishes downloading, finish the hash and generate a notice.
event http_message_done(c: connection, is_orig: bool, stat: http_message_stat) &priority=-3
{
if ( is_orig || ! c?$http ) return;
if ( c$http?$md5_handle )
{
local url = build_url_http(c$http);
c$http$md5 = md5_hash_finish(c$http$md5_handle);
delete c$http$md5_handle;
NOTICE([$note=MD5, $msg=fmt("%s %s %s", c$id$orig_h, c$http$md5, url),
$sub=c$http$md5, $conn=c, $URL=url]);
}
}
event connection_state_remove(c: connection) &priority=-5
{
if ( c?$http_state &&
c$http_state$current_response in c$http_state$pending &&
c$http_state$pending[c$http_state$current_response]?$md5_handle )
{
# The MD5 sum isn't going to be saved anywhere since the entire
# body wouldn't have been seen anyway and we'd just be giving an
# incorrect MD5 sum.
md5_hash_finish(c$http$md5_handle);
delete c$http$md5_handle;
}
}