GitHub workflow: Add Alpine Linux job

[Antelox]

Added a job to run build & test into a musl-based linux distribution like Alpine. This should extend coverage and be sure things keep working fine

Related issues:

• Building unicorn from source on Alpine fails with /home/venom/mtkclient/unicorn/qemu/util/oslib-posix.c:33:10: fatal error: linux/mman.h: No such file or directory #1965
• test_uc_hook_cached_uaf test fails with SIGSEGV after building on x86 with musl #2113

[wtdcode]

@PhilippTakacs

This workflow reveals a UAF bug. Reproduction it with:

mkdir build
cd build 
cmake .. -DCMAKE_EXPORT_COMPILE_COMMANDS=y -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_FLAGS=-fsanitize=address
make -j
./test_mem test_snapshot

This gives:

Test test_snapshot...                           =================================================================
==2000659==ERROR: AddressSanitizer: heap-use-after-free on address 0x60e0000005dc at pc 0x7fdd650b3675 bp 0x7ffebe9070e0 sp 0x7ffebe9070d0
READ of size 4 at 0x60e0000005dc thread T0
    #0 0x7fdd650b3674 in address_space_dispatch_clear_x86_64 /home/mio/opensource/unicorn/qemu/exec.c:1466
    #1 0x7fdd650c3c92 in flatview_copy_x86_64 /home/mio/opensource/unicorn/qemu/softmmu/memory.c:945
    #2 0x7fdd6507e4f6 in uc_context_restore /home/mio/opensource/unicorn/uc.c:2450
    #3 0x5651d49fbdfa in test_snapshot /home/mio/opensource/unicorn/tests/unit/test_mem.c:305
    #4 0x5651d49f3da8 in acutest_do_run_ /home/mio/opensource/unicorn/tests/unit/acutest.h:1027
    #5 0x5651d49f4501 in acutest_run_ /home/mio/opensource/unicorn/tests/unit/acutest.h:1234
    #6 0x5651d49f6b96 in main /home/mio/opensource/unicorn/tests/unit/acutest.h:1832
    #7 0x7fdd64629d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #8 0x7fdd64629e3f in __libc_start_main_impl ../csu/libc-start.c:392
    #9 0x5651d49f1ac4 in _start (/home/mio/opensource/unicorn/build/test_mem+0x7ac4)

0x60e0000005dc is located 92 bytes inside of 160-byte region [0x60e000000580,0x60e000000620)
freed by thread T0 here:
    #0 0x7fdd67eb4537 in __interceptor_free ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:127
    #1 0x7fdd6508fcca in g_free /home/mio/opensource/unicorn/glib_compat/gmem.c:256
    #2 0x7fdd650be1fc in memory_region_filter_subregions_x86_64 /home/mio/opensource/unicorn/qemu/softmmu/memory.c:222
    #3 0x7fdd650817c5 in uc_restore_latest_snapshot /home/mio/opensource/unicorn/uc.c:2881
    #4 0x7fdd6507e353 in uc_context_restore /home/mio/opensource/unicorn/uc.c:2442
    #5 0x5651d49fbdfa in test_snapshot /home/mio/opensource/unicorn/tests/unit/test_mem.c:305
    #6 0x5651d49f3da8 in acutest_do_run_ /home/mio/opensource/unicorn/tests/unit/acutest.h:1027
    #7 0x5651d49f4501 in acutest_run_ /home/mio/opensource/unicorn/tests/unit/acutest.h:1234
    #8 0x5651d49f6b96 in main /home/mio/opensource/unicorn/tests/unit/acutest.h:1832
    #9 0x7fdd64629d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

previously allocated by thread T0 here:
    #0 0x7fdd67eb4887 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x7fdd6508fb18 in g_malloc /home/mio/opensource/unicorn/glib_compat/gmem.c:93
    #2 0x7fdd6508fb64 in g_malloc_n /home/mio/opensource/unicorn/glib_compat/gmem.c:122
    #3 0x7fdd650bd4f9 in memory_cow_x86_64 /home/mio/opensource/unicorn/qemu/softmmu/memory.c:100
    #4 0x7fdd65150a49 in store_helper /home/mio/opensource/unicorn/qemu/accel/tcg/cputlb.c:2228
    #5 0x7fdd651514d0 in helper_le_stl_mmu_x86_64 /home/mio/opensource/unicorn/qemu/accel/tcg/cputlb.c:2390
    #6 0x7fdd212003b5  (<unknown module>)

SUMMARY: AddressSanitizer: heap-use-after-free /home/mio/opensource/unicorn/qemu/exec.c:1466 in address_space_dispatch_clear_x86_64
Shadow bytes around the buggy address:
  0x0c1c7fff8060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c1c7fff8070: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c1c7fff8080: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
  0x0c1c7fff8090: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c1c7fff80a0: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa
=>0x0c1c7fff80b0: fd fd fd fd fd fd fd fd fd fd fd[fd]fd fd fd fd
  0x0c1c7fff80c0: fd fd fd fd fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1c7fff80d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1c7fff80e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1c7fff80f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1c7fff8100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==2000659==ABORTING

The underlying memory regions are accessed after free. Would you like to draft a fix?

[PhilippTakacs]

The underlying memory regions are accessed after free. Would you like to draft a fix?

Yes, I'm working on it.

[wtdcode]

The underlying memory regions are accessed after free. Would you like to draft a fix?

Yes, I'm working on it.

Thanks!

By the way, please draft a standalone PR to master branch directly as we are releasing 2.1.3 shortly.