Memory Leak Testing

[pilsnerfrajz]

Memory Leak Testing

Add memory leak testing with the AddressSanitizer available in clang. Closes #16.

Tests

• Update Makefile to run tests easily
  • make leaks runs leak tests based on different command line args
  • make test checks the separate functions in disco for leaks
    • Also runs make leaks
  • Add tests/leaks.sh to print sanitizer output in a user-friendly way when running multiple tests:

✅ Leak test with arguments '-h': passed
✅ Leak test with arguments '--help': passed
✅ Leak test with arguments '': passed
tests/leaks.sh: line 5: 34509 Abort trap: 6           $BIN "$@" > /dev/null 2> "$ERR_LOG"
❌ Leak test with arguments 'localhost -P': failed
=================================================================
==34509==ERROR: AddressSanitizer: heap-use-after-free on address 0x604000000a94 at pc 0x000102c00240 bp 0x00016d205f50 sp 0x00016d205f48
READ of size 4 at 0x604000000a94 thread T0
    #0 0x000102c0023c in ping ping.c:286
    #1 0x000102bfce20 in main main.c:315
    #2 0x0001846fdd50  (<unknown module>)

0x604000000a94 is located 4 bytes inside of 48-byte region [0x604000000a90,0x604000000ac0)
freed by thread T0 here:
    #0 0x000103411400 in free+0x7c (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3d400)
    #1 0x000102c07318 in free_dst_addr_struct utils.c:21
    #2 0x000102c000ac in ping ping.c:258
    #3 0x000102bfce20 in main main.c:315
    #4 0x0001846fdd50  (<unknown module>)

previously allocated by thread T0 here:
    #0 0x00010341130c in malloc+0x78 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3d30c)
    #1 0x000102c07690 in get_dst_addr_struct utils.c:70
    #2 0x000102bffd48 in ping ping.c:213
    #3 0x000102bfce20 in main main.c:315
    #4 0x0001846fdd50  (<unknown module>)

SUMMARY: AddressSanitizer: heap-use-after-free ping.c:286 in ping
Shadow bytes around the buggy address:
...

• Minor formatting fixes

Fix Memory Leaks

The tests revealed multiple leaks which are now fixed:

• pcap_compile() filters where not freed in src/arp.c or src/syn_scan.c
• The if_name variable was not freed in src/arp.c
• Incorrect memory allocation in src/utils.c caused copying of bytes outside of allocated memory
• if was used instead of else if in src/ping.c which caused a use-after-free of the dst variable

README

Update README

• Remove outdated info
• Update ToC
• Update Testing section
  • Break up integration tests and memory leaks tests into their own sections