Commit Graph

6 Commits

Author SHA1 Message Date
João Valverde 9c4a42c07c wmem: Rename some variables
Use length and size consistently. strbuf->len does not
include the terminating nul. strbuf->alloc_len includes
the terminating nul.

Use consistent language and use "length" to mean size without
nul byte and "size" to mean size with all bytes, including nul.
2022-09-27 18:59:00 +01:00
João Valverde 6d06d4e46b Add some UTF-8 debug checks with a compile time flag
Some older dissectors that predate Unicode and parse text protocols
are prone to generate invalid UTF-8 strings. This is a bug and can have
safety implications.

For example passing invalid UTF-8 to proto_tree_add_string() is a
common bug. There are safeguards in format_text() but this should
not be relied on as a general solution to the problem.

For one, as the name implies, it is only used with representation of a
field value, which is not the same as the value itself of an FT_STRING field.
Issue #18317 shows another reason why.

For now this compile flag only enables extra checks for string ftypes,
which covers a subset of proto.h APIs including
proto_tree_append_string(). Later is should be extended to other
interfaces.

This is also not expected to be disabled for release builds because
there are still many dissectors that do not correctly handle strings.
More work is needed to 1) identify them and 2) fix them.

Ping #18317
2022-09-27 17:04:44 +00:00
João Valverde 47348ae598 dfilter: Add support for literal strings with null bytes
Before:
    Filter: frame matches "abc\x00def"
    dftest: \x00 (NUL byte) cannot be used with a regular string.
    	frame matches "abc\x00def"
    	                  ^~~~
    Filter: _ws.ftypes.string == "a string with a \0 byte"
    dftest: \0 (NUL byte) cannot be used with a regular string.
    	_ws.ftypes.string == "a string with a \0 byte"
    	                                      ^~

After:
    Filter: frame matches "abc\x00def"

    Syntax tree:
     0 TEST_MATCHES:
       1 FIELD(frame)
       1 PCRE(abc\0def)

    Instructions:
    00000 READ_TREE		frame -> reg#0
    00001 IF_FALSE_GOTO	3
    00002 ANY_MATCHES	reg#0 matches abc\0def
    00003 RETURN

    Filter: _ws.ftypes.string == "a string with a \0 byte"

    Syntax tree:
     0 TEST_ANY_EQ:
       1 FIELD(_ws.ftypes.string)
       1 FVALUE("a string with a \0 byte" <FT_STRING>)

    Instructions:
    00000 READ_TREE		_ws.ftypes.string -> reg#0
    00001 IF_FALSE_GOTO	3
    00002 ANY_EQ		reg#0 == "a string with a \0 byte" <FT_STRING>
    00003 RETURN

Fixes issue #16156.
2022-06-21 15:10:08 +00:00
Moshe Kaplan 1c3a9af869 Add files with WS_DLL_PUBLIC to Doxygen
Add @file markers for most files that
contain functions exported with
WS_DLL_PUBLIC so that Doxygen will
generate documentation for them.
2021-11-29 21:27:45 +00:00
João Valverde 925e01b23f Remove duplicate format_size() function
We have two format_size()s, with and without wmem scoped memory.
Move the wmem version to wsutil and add a convenience macro to
use g_malloc()ed memory.
2021-07-26 14:56:11 +00:00
João Valverde 7f9c1f5f92 Move wmem to wsutil
This allows wmem to be used from other libraries, namely wsutil.
It is often the case that a funtion exists in wsutil and cannot
be used with a wmem scope, requiring some code duplication or
extra memory allocations, or vice-versa, code in epan cannot be
moved to wsutil because it has a wmem dependency.

To this end wmem is moved to wsutil. Scope management remains part
of epan because those scope semantics are specific to dissection.
2021-07-26 14:56:11 +00:00