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Refactoring of Base64 functions.

Browse source 
Base64Converter now uses a connection directly, instead of an analyzer
redirecting to the underlying connection for reporting to Weird. The new
built-in functions en-/decode_base64_intern make use of this to send
encoding-errors to Weird instead of Reporter.

According to the documentation, using the empty string as alphabet in
the built-in functions, will use the default alphabet. Therefore the
built-in functions can now use default arguments and
en-/decode_base64_custom is deprecated.

The tests have been updated accordingly.
This commit is contained in:
Jan Grashoefer 2015-08-04 15:46:24 +02:00
parent 4c2aa804e1
commit 8f3ded5e2d
8 changed files with 136 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

16
src/Base64.cc
View file

@ -82,7 +82,7 @@ int* Base64Converter::InitBase64Table(const string& alphabet)
return base64_table;
}
Base64Converter::Base64Converter(analyzer::Analyzer* arg_analyzer, const string& arg_alphabet)
Base64Converter::Base64Converter(Connection* arg_conn, const string& arg_alphabet)
{
if ( arg_alphabet.size() > 0 )
{
@ -98,7 +98,7 @@ Base64Converter::Base64Converter(analyzer::Analyzer* arg_analyzer, const string&
base64_group_next = 0;
base64_padding = base64_after_padding = 0;
errored = 0;
analyzer = arg_analyzer;
conn = arg_conn;
}
Base64Converter::~Base64Converter()
@ -216,9 +216,9 @@ int Base64Converter::Done(int* pblen, char** pbuf)
}
BroString* decode_base64(const BroString* s, const BroString* a)
BroString* decode_base64(const BroString* s, const BroString* a, Connection* conn)
{
if ( a && a->Len() != 64 )
if ( a && a->Len() != 0 && a->Len() != 64 )
{
reporter->Error("base64 decoding alphabet is not 64 characters: %s",
a->CheckString());
@ -229,7 +229,7 @@ BroString* decode_base64(const BroString* s, const BroString* a)
int rlen2, rlen = buf_len;
char* rbuf2, *rbuf = new char[rlen];
Base64Converter dec(0, a ? a->CheckString() : "");
Base64Converter dec(conn, a ? a->CheckString() : "");
if ( dec.Decode(s->Len(), (const char*) s->Bytes(), &rlen, &rbuf) == -1 )
goto err;
@ -248,9 +248,9 @@ err:
return 0;
}
BroString* encode_base64(const BroString* s, const BroString* a)
BroString* encode_base64(const BroString* s, const BroString* a, Connection* conn)
{
if ( a && a->Len() != 64 )
if ( a && a->Len() != 0 && a->Len() != 64 )
{
reporter->Error("base64 alphabet is not 64 characters: %s",
a->CheckString());
@ -259,7 +259,7 @@ BroString* encode_base64(const BroString* s, const BroString* a)
char* outbuf = 0;
int outlen = 0;
Base64Converter enc(0, a ? a->CheckString() : "");
Base64Converter enc(conn, a ? a->CheckString() : "");
enc.Encode(s->Len(), (const unsigned char*) s->Bytes(), &outlen, &outbuf);
return new BroString(1, (u_char*)outbuf, outlen);

19
src/Base64.h
View file

@ -8,15 +8,16 @@
#include "util.h"
#include "BroString.h"
#include "Reporter.h"
#include "analyzer/Analyzer.h"
#include "Conn.h"
// Maybe we should have a base class for generic decoders?
class Base64Converter {
public:
// <analyzer> is used for error reporting, and it should be zero when
// the decoder is called by the built-in function decode_base64() or encode_base64().
// <conn> is used for error reporting. If it is set to zero, e.g. done by the
// built-in functions decode_base64() and encode_base64(), encoding-errors will
// go to Reporter instead of Weird. Usage-errors go to Reporter in any case.
// Empty alphabet indicates the default base64 alphabet.
Base64Converter(analyzer::Analyzer* analyzer, const string& alphabet = "");
Base64Converter(Connection* conn, const string& alphabet = "");
~Base64Converter();
// A note on Decode():
@ -42,8 +43,8 @@ public:
void IllegalEncoding(const char* msg)
{
// strncpy(error_msg, msg, sizeof(error_msg));
if ( analyzer )
analyzer->Weird("base64_illegal_encoding", msg);
if ( conn )
conn->Weird("base64_illegal_encoding", msg);
else
reporter->Error("%s", msg);
}
@ -63,11 +64,11 @@ protected:
int base64_after_padding;
int* base64_table;
int errored; // if true, we encountered an error - skip further processing
analyzer::Analyzer* analyzer;
Connection* conn;
};
BroString* decode_base64(const BroString* s, const BroString* a = 0);
BroString* encode_base64(const BroString* s, const BroString* a = 0);
BroString* decode_base64(const BroString* s, const BroString* a = 0, Connection* conn = 0);
BroString* encode_base64(const BroString* s, const BroString* a = 0, Connection* conn = 0);
#endif /* base64_h */

10
src/analyzer/protocol/mime/MIME.cc
View file

@ -1116,13 +1116,21 @@ void MIME_Entity::DecodeBase64(int len, const char* data)
void MIME_Entity::StartDecodeBase64()
{
analyzer::Analyzer* analyzer = message->GetAnalyzer();
Connection* conn = 0;
if ( base64_decoder )
{
reporter->InternalWarning("previous MIME Base64 decoder not released");
delete base64_decoder;
}
base64_decoder = new Base64Converter(message->GetAnalyzer());
if( analyzer )
conn = analyzer->Conn();
else
reporter->InternalWarning("no analyzer associated with MIME message");
base64_decoder = new Base64Converter(conn);
}
void MIME_Entity::FinishDecodeBase64()

94
src/bro.bif
View file

@ -2723,14 +2723,51 @@ function hexstr_to_bytestring%(hexstr: string%): string
## Encodes a Base64-encoded string.
##
## s: The string to encode
## s: The string to encode.
##
## a: The custom alphabet. The empty string indicates the default alphabet. The
## length of *a* must be 64. For example, a custom alphabet could be
## ``"!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?"``.
##
## Returns: The encoded version of *s*.
##
## .. bro:see:: encode_base64_custom decode_base64
function encode_base64%(s: string%): string
## .. bro:see:: encode_base64_intern decode_base64
function encode_base64%(s: string, a: string &default=""%): string
%{
BroString* t = encode_base64(s->AsString());
BroString* t = encode_base64(s->AsString(), a->AsString());
if ( t )
return new StringVal(t);
else
{
reporter->Error("error in encoding string %s", s->CheckString());
return new StringVal("");
}
%}
## Encodes a Base64-encoded string.
##
## cid: The connection identifier, identifiying the connection which is used to
## handle encoding-errors (errors will go to Weird).
##
## s: The string to encode.
##
## a: The custom alphabet. The empty string indicates the default alphabet. The
## length of *a* must be 64. For example, a custom alphabet could be
## ``"!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?"``.
##
## Returns: The encoded version of *s*.
##
## .. bro:see:: encode_base64 decode_base64_intern
function encode_base64_intern%(cid: conn_id, s: string, a: string &default=""%): string
%{
Connection* conn = sessions->FindConnection(cid);
if ( ! conn )
{
builtin_error("connection ID not a known connection", cid);
return new StringVal("");
}
BroString* t = encode_base64(s->AsString(), a->AsString(), conn);
if ( t )
return new StringVal(t);
else
@ -2742,7 +2779,7 @@ function encode_base64%(s: string%): string
## Encodes a Base64-encoded string with a custom alphabet.
##
## s: The string to encode
## s: The string to encode.
##
## a: The custom alphabet. The empty string indicates the default alphabet. The
## length of *a* must be 64. For example, a custom alphabet could be
@ -2751,7 +2788,7 @@ function encode_base64%(s: string%): string
## Returns: The encoded version of *s*.
##
## .. bro:see:: encode_base64 decode_base64_custom
function encode_base64_custom%(s: string, a: string%): string
function encode_base64_custom%(s: string, a: string%): string &deprecated
%{
BroString* t = encode_base64(s->AsString(), a->AsString());
if ( t )
@ -2767,12 +2804,49 @@ function encode_base64_custom%(s: string, a: string%): string
##
## s: The Base64-encoded string.
##
## a: The custom alphabet. The empty string indicates the default alphabet. The
## length of *a* must be 64. For example, a custom alphabet could be
## ``"!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?"``.
##
## Returns: The decoded version of *s*.
##
## .. bro:see:: decode_base64_custom encode_base64
function decode_base64%(s: string%): string
## .. bro:see:: decode_base64_intern encode_base64
function decode_base64%(s: string, a: string &default=""%): string
%{
BroString* t = decode_base64(s->AsString());
BroString* t = decode_base64(s->AsString(), a->AsString());
if ( t )
return new StringVal(t);
else
{
reporter->Error("error in decoding string %s", s->CheckString());
return new StringVal("");
}
%}
## Decodes a Base64-encoded string.
##
## cid: The connection identifier, identifiying the connection which is used to
## handle encoding-errors (errors will go to Weird).
##
## s: The Base64-encoded string.
##
## a: The custom alphabet. The empty string indicates the default alphabet. The
## length of *a* must be 64. For example, a custom alphabet could be
## ``"!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?"``.
##
## Returns: The decoded version of *s*.
##
## .. bro:see:: decode_base64 encode_base64_intern
function decode_base64_intern%(cid: conn_id, s: string, a: string &default=""%): string
%{
Connection* conn = sessions->FindConnection(cid);
if ( ! conn )
{
builtin_error("connection ID not a known connection", cid);
return new StringVal("");
}
BroString* t = decode_base64(s->AsString(), a->AsString(), conn);
if ( t )
return new StringVal(t);
else
@ -2793,7 +2867,7 @@ function decode_base64%(s: string%): string
## Returns: The decoded version of *s*.
##
## .. bro:see:: decode_base64 encode_base64_custom
function decode_base64_custom%(s: string, a: string%): string
function decode_base64_custom%(s: string, a: string%): string &deprecated
%{
BroString* t = decode_base64(s->AsString(), a->AsString());
if ( t )

8
testing/btest/Baseline/bifs.decode_base64/out
View file

@ -4,3 +4,11 @@ bro
bro
bro
bro
bro
bro
bro
bro
bro
bro
bro
bro

4
testing/btest/Baseline/bifs.encode_base64/out
View file

@ -1,5 +1,9 @@
YnJv
YnJv
YnJv
}n-v
YnJv
YnJv
}n-v
cGFkZGluZw==
cGFkZGluZzE=

8
testing/btest/bifs/decode_base64.bro
View file

@ -6,9 +6,17 @@ global default_alphabet: string = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrs
global my_alphabet: string = "!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?";
print decode_base64("YnJv");
print decode_base64("YnJv", default_alphabet);
print decode_base64("YnJv", ""); # should use default alpabet
print decode_base64("}n-v", my_alphabet);
print decode_base64_custom("YnJv", default_alphabet);
print decode_base64_custom("YnJv", ""); # should use default alpabet
print decode_base64_custom("}n-v", my_alphabet);
print decode_base64("YnJv");
print decode_base64("YnJv", default_alphabet);
print decode_base64("YnJv", ""); # should use default alpabet
print decode_base64("}n-v", my_alphabet);
print decode_base64_custom("YnJv", default_alphabet);
print decode_base64_custom("YnJv", ""); # should use default alpabet
print decode_base64_custom("}n-v", my_alphabet);

5
testing/btest/bifs/encode_base64.bro
View file

@ -6,7 +6,12 @@ global default_alphabet: string = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrs
global my_alphabet: string = "!#$%&/(),-.:;<>@[]^ `_{|}~abcdefghijklmnopqrstuvwxyz0123456789+?";
print encode_base64("bro");
print encode_base64("bro", default_alphabet);
print encode_base64("bro", ""); # should use default alpabet
print encode_base64("bro", my_alphabet);
print encode_base64_custom("bro", default_alphabet);
print encode_base64_custom("bro", ""); # should use default alpabet
print encode_base64_custom("bro", my_alphabet);
print encode_base64("padding");