This patch adds experimental-quality CMake build tooling.
The libmspack build required a modification to use "" instead of <> for
header #includes. This will hopefully be included in the libmspack
upstream project when adding CMake build tooling to libmspack.
Removed use of libltdl when using CMake.
Flex & Bison are now required to build.
If -DMAINTAINER_MODE, then GPERF is also required, though it currently
doesn't actually do anything. TODO!
I found that the autotools build system was generating the lexer output
but not actually compiling it, instead using previously generated (and
manually renamed) lexer c source. As a consequence, changes to the .l
and .y files weren't making it into the build. To resolve this, I
removed generated flex/bison files and fixed the tooling to use the
freshly generated files. Flex and bison are now required build tools.
On Windows, this adds a dependency on the winflexbison package,
which can be obtained using Chocolatey or may be manually installed.
CMake tooling only has partial support for building with external LLVM
library, and no support for the internal LLVM (to be removed in the
future). I.e. The CMake build currently only supports the bytecode
interpreter.
Many files used include paths relative to the top source directory or
relative to the current project, rather than relative to each build
target. Modern CMake support requires including internal dependency
headers the same way you would external dependency headers (albeit
with "" instead of <>). This meant correcting all header includes to
be relative to the build targets and not relative to the workspace.
For example, ...
```c
include "../libclamav/clamav.h"
include "clamd/clamd_others.h"
```
... becomes:
```c
// libclamav
include "clamav.h"
// clamd
include "clamd_others.h"
```
Fixes header name conflicts by renaming a few of the files.
Converted the "shared" code into a static library, which depends on
libclamav. The ironically named "shared" static library provides
features common to the ClamAV apps which are not required in
libclamav itself and are not intended for use by downstream projects.
This change was required for correct modern CMake practices but was
also required to use the automake "subdir-objects" option.
This eliminates warnings when running autoreconf which, in the next
version of autoconf & automake are likely to break the build.
libclamav used to build in multiple stages where an earlier stage is
a static library containing utils required by the "shared" code.
Linking clamdscan and clamdtop with this libclamav utils static lib
allowed these two apps to function without libclamav. While this is
nice in theory, the practical gains are minimal and it complicates
the build system. As such, the autotools and CMake tooling was
simplified for improved maintainability and this feature was thrown
out. clamdtop and clamdscan now require libclamav to function.
Removed the nopthreads version of the autotools
libclamav_internal_utils static library and added pthread linking to
a couple apps that may have issues building on some platforms without
it, with the intention of removing needless complexity from the
source. Kept the regular version of libclamav_internal_utils.la
though it is no longer used anywhere but in libclamav.
Added an experimental doxygen build option which attempts to build
clamav.h and libfreshclam doxygen html docs.
The CMake build tooling also may build the example program(s), which
isn't a feature in the Autotools build system.
Changed C standard to C90+ due to inline linking issues with socket.h
when linking libfreshclam.so on Linux.
Generate common.rc for win32.
Fix tabs/spaces in shared Makefile.am, and remove vestigial ifndef
from misc.c.
Add CMake files to the automake dist, so users can try the new
CMake tooling w/out having to build from a git clone.
clamonacc changes:
- Renamed FANOTIFY macro to HAVE_SYS_FANOTIFY_H to better match other
similar macros.
- Added a new clamav-clamonacc.service systemd unit file, based on
the work of ChadDevOps & Aaron Brighton.
- Added missing clamonacc man page.
Updates to clamdscan man page, add missing options.
Remove vestigial CL_NOLIBCLAMAV definitions (all apps now use
libclamav).
Rename Windows mspack.dll to libmspack.dll so all ClamAV-built
libraries have the lib-prefix with Visual Studio as with CMake.
Changes cli_checkfp_virus to a recursive function which checks all
parent fmaps in the context for false positives
Simplifies params needed for cli_checkfp_virus to use the current digest
and fmap length that resides within the fmap struct itself
Looking through the list of issues, I spotted some easy ones and submitted
some fixes:
- 225229 - In cli_rarload: Leak of memory or pointers to system resources.
If finding the necessary libunrar functions fails (should be rare),we now
dlclose libunrar.
225224 - In main (freshclam.c): A copied piece of code is inconsistent with
the original (CWE-398). A minor copy-paste error was present, and optOutList
could be cleaned up in one of the failure edge cases.
225228 - In decodecdb: Out-of-bounds access to a buffer (CWE-119). Off by one
error when tokenizing certain CDB sig fields for printing with sigtool. Ex:
$ cat test.cdb
a:CL_TYPE_7Z:1-2-3:/.*/:1-2-3:1-2-3:0:1-2-3::
$ cat test.cdb | ../installed/bin/sigtool --decode
VIRUS NAME: a
CONTAINER TYPE: CL_TYPE_7Z
CONTAINER SIZE: WITHIN RANGE 1 to 2
FILENAME REGEX: /.*/
COMPRESSED FILESIZE: WITHIN RANGE 1 to 2
UNCOMPRESSED FILESIZE: WITHIN RANGE 1 to 2
ENCRYPTION: NO
FILE POSITION: =================================================================
==17245==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fffe3136d10 at pc 0x7f0f31c3f414 bp 0x7fffe3136c70 sp 0x7fffe3136c60
WRITE of size 8 at 0x7fffe3136d10 thread T0
#0 0x7f0f31c3f413 in cli_strtokenize ../../libclamav/str.c:524
#1 0x559e9797dc91 in decodecdb ../../sigtool/sigtool.c:2929
#2 0x559e9797ea66 in decodesig ../../sigtool/sigtool.c:3058
#3 0x559e9797f31e in decodesigs ../../sigtool/sigtool.c:3162
#4 0x559e97981fbc in main ../../sigtool/sigtool.c:3638
#5 0x7f0f3100fb96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
#6 0x559e9795a1d9 in _start (/home/zelda/workspace/clamav-devel/installed/bin/sigtool+0x381d9)
Address 0x7fffe3136d10 is located in stack of thread T0 at offset 48 in frame
#0 0x559e9797d113 in decodecdb ../../sigtool/sigtool.c:2840
This frame has 1 object(s):
[32, 48) 'range' <== Memory access at offset 48 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow ../../libclamav/str.c:524 in cli_strtokenize
- 225223 - In cli_egg_deflate_decompress: Reads an uninitialized pointer or
its target (CWE-457). Certain fail cases would call inflateEnd on an
uninitialized stream. Now it’s only called after initialization occurs.
- 225220 - In buildcld: Use of an uninitialized variable (CWE-457). Certain
fail cases would result in oldDir being used before initialization. It now
gets zeroed before the first fail case.
- 225219 - In cli_egg_open: Leak of memory or pointers to system resources
(CWE-404). If certain realloc’s failed, several structures would not be cleaned up
- 225218 - In cli_scanhwpml: Code block is unreachable because of the syntactic
structure of the code (CWE-561). With certain macros set, there could be two
consecutive return statements.
Some detections, like phishing, are considered heuristic alerts because
they match based on behavior more than on content. A subset of these
are considered "potentially unwanted" (low-severity). These
low-severity alerts include:
- phishing
- PDFs with obfuscated object names
- bytecode signature alerts that start with "BC.Heuristics"
The concept is that unless you enable "heuristic precedence" (a method
of lowing the threshold to immediateley alert on low-severity
detections), the scan should continue after a match in case a higher
severity match is found. Only at the end will it print the low-severity
match if nothing else was found.
The current implementation is buggy though. Scanning of archives does
not correctly bail out for the entire archive if one email contains a
phishing link. Instead, it sets the "heuristic found" flag then and
alerts for every subsequent file in the archive because it doesn't know
if the heuristic was found in an embedded file or the target file.
Because it's just a heuristic and the status is "clean", it keeps
scanning.
This patch corrects the behavior by checking if a low-severity alerts
were found at the end of scanning the target file, instead of at the end
of each embedded file.
Additionally, this patch fixes an in issue with phishing alerts wherein
heuristic precedence mode did not cause a scan to stop after the first
alert.
The above changes required restructuring to create an fmap inside of
cl_scandesc_callback() so that scan_common() could be modified to
require an fmap and set up so that the current *ctx->fmap pointer is
never NULL when scan_common() evaluates match results.
Also fixed a couple minor bugs in the phishing unit tests and cleaned up
the test code for improved legitibility and type safety.
This commit improves the layout of the tmp file output and the JSON
metadata output when using the --leave-temps and --gen-json options.
For all scans, each scan target will get a unique tmp sub-directory. If
using --leave-temps, that subdir will include the basename of the
original file to make it easier to identify. Additionally, when using
--leave-temps option, all extracted objects will have their
subdirectories extracted in recursive subdirectories including filename
prefixes where available. When not using the --leave-temps option, the
layout of the tmp sub-directory will remain flat, so as to alleviate the
possibility of exceeding PATH_MAX.
The JSON metadata generated by the --gen-json option is now generated
for all file types, not just a select few. The format is also
pretty-printed for readability and now includes filenames and file paths
when available.
Also:
- Added missing ALLMATCH check when determining if bytecode hooks should
be run.
- Added cl_engine_get_str API to windows libclamav symbol export file.
Instead of checking the Authenticode header as an FP prevention
mechanism, we now check it in the beginning if it exists. Also,
we can now do actual blacklisting with .crb rules (previously, a
blacklist rule just let you override a whitelist rule).
Updated libclamav documentation detailing new scan options structure.
Renamed references to 'algorithmic' detection to 'heuristic' detection. Renaming references to 'properties' to 'collect metadata'.
Renamed references to 'scan all' to 'scan all match'.
Renamed a couple of 'Hueristic.*' signature names as 'Heuristics.*' signatures (plural) to match majority of other heuristics.
Micah Snyder (micasnyd)