Upload fuzz_ppd harness

[k-furman]

Add fuzz_ppd harness for fuzzing,
add build rules and seed corpus files.
This harness has been tested on the aflplusplus/aflplusplus docker container with these specifications:

/ # cat /etc/debian_version 
bookworm/sid
/ # clang --version
Ubuntu clang version 16.0.6 (++20231112100510+7cbf1a259152-1~exp1~20231112100554.106)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

Project was built this way:

CC=afl-clang-lto
CXX=afl-clang-lto++
AFL_USE_ASAN=1
./configure --enable-static --disable-shared --host=x86_64
make -C cups/
make -C fuzzer/

Fuzzing runs like this:

afl-fuzz -i in/ -o out/ ./fuzz_ppd @@

Works well for afl-fuzz.

[fish98]

Thank you for your contribution. The code looks good to me but please allow some time for testing the availability of the harness before merging, so it can be adopted into the OSS-Fuzz testing loop.

Meanwhile, In line with the Open Source principles upheld by OpenPrinting, could you provide either the script (not the binary) or a description of how to generate the newly added three fuzz corpora located in projects/cups/seeds/fuzz_ppd_seed_corpus/*? It will enable everyone to reproduce the generated binary seed :)

[k-furman]

The seed files for this harness can be generated this way, where cups/test.ppd and cups/test2.ppd - are original ppd files from the cups project:

echo -n -e "Letter\0na-letter\0roll_max_36.1025x3622.0472in\0 4x6\0Foo\0foo=buz option=option Foo=Buz tag=fooz\0datanum1920\0datanum1080\0" > 1
cat cups/test.ppd >> 1

echo -n -e "A4\0Letter\0iso_a4_210x297mm\0 2x8\0Option\0Option=Bar Foo=Buz AL=666 Astra=Aspera\0datanum1337\0datanum4242\0 " > 2
cat cups/test2.ppd >> 2

echo -n -e "A4\0A4\0iso_a4_210x297mm\0 2x8\0Astra\0Per=Aspera Ad=Astra\0datanum2048\0datanum2048\0 " > 3
cat cups/test2.ppd >> 3

Arguments separated by '\0' because of the use of the strdup() function, which can guarantee that the string is null-terminated to prevent overflows and incorrect function calls.

[fish98]

The seed files for this harness can be generated this way, where cups/test.ppd and cups/test2.ppd - are original ppd files from the cups project:

echo -n -e "Letter\0na-letter\0roll_max_36.1025x3622.0472in\0 4x6\0Foo\0foo=buz option=option Foo=Buz tag=fooz\0datanum1920\0datanum1080\0" > 1
cat cups/test.ppd >> 1

echo -n -e "A4\0Letter\0iso_a4_210x297mm\0 2x8\0Option\0Option=Bar Foo=Buz AL=666 Astra=Aspera\0datanum1337\0datanum4242\0 " > 2
cat cups/test2.ppd >> 2

echo -n -e "A4\0A4\0iso_a4_210x297mm\0 2x8\0Astra\0Per=Aspera Ad=Astra\0datanum2048\0datanum2048\0 " > 3
cat cups/test2.ppd >> 3

Arguments separated by '\0' because of the use of the strdup() function, which can guarantee that the string is null-terminated to prevent overflows and incorrect function calls.

Thank you for the detailed documentation regarding the fuzzing corpora. I will update the corresponding README.

The local building for fuzz_ppd pops direct memory leak caused by unhandled variables such as ppdsize and cups_options (similar types). I will take some free time to address these false positives before finally merging them into the productive main branch :)

[k-furman]

Ok! Thank you so much!

[k-furman]

Just a friendly reminder.

[fish98]

Many thanks for your contribution! Currently the harness still exhibits memory-related issues within the OSS-Fuzz framework. The memory allocation within the harness requires revisions to properly manage the memory lifecycle. We will enable the harness after fixing this problem :)