relocation R_X86_64_PC32 against absolute symbol _binary_python_extension_py_size' in section .text' is disallowed

[oxr463]

Expected Behavior

Building a PRoot binary.

Actual Behavior

Python extension error when building.

Steps to Reproduce the Problem

make -C src loader.elf loader-m32.elf build.h
make -C src proot

Specifications

• Proot/Care version: 8c0ccf7
• Kernel version: Linux 49c896f37a82 5.11.0-7612-generic #13~1617215757~20.10~97a8d1a-Ubuntu SMP Thu Apr 1 21:09:17 UTC 2 x86_64 GNU/Linux
• Host distribution: Pop!_OS v20.10
• Guest distribution: Alpine v3.13.0

Command Output

make -C src proot
make: Entering directory '/usr/src/proot/src'
  LD	proot
/usr/lib/gcc/x86_64-alpine-linux-musl/10.2.1/../../../../x86_64-alpine-linux-musl/bin/ld: extension/python/python.o: relocation R_X86_64_PC32 against absolute symbol `_binary_python_extension_py_size' in section `.text' is disallowed
collect2: error: ld returned 1 exit status
make: *** [GNUmakefile:179: proot] Error 1
make: Leaving directory '/usr/src/proot/src'

[oxr463]

See: https://stac47.github.io/c/relocation/elf/tutorial/2018/03/01/understanding-relocation-elf.html

[oxr463]

This might be specific to Alpine due to musl libc. I was able to build without any issues on Debian 10.

[chewi]

I've hit this on Gentoo with glibc. Perhaps it's GCC 11.2.

[oxr463]

I've hit this on Gentoo with glibc. Perhaps it's GCC 11.2.

Ah... That's interesting. Let me see if I can reproduce on an older version.

[oxr463]

cat /etc/os-release 
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.14.2
PRETTY_NAME="Alpine Linux v3.14"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://bugs.alpinelinux.org/"

gcc --version
gcc (Alpine 10.3.1_git20210424) 10.3.1 20210424
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[oxr463]

This has been fixed.

make -C src proot
make: Entering directory '/usr/src/proot/src'
  CC	cli/cli.o
  CC	cli/proot.o
  CC	cli/note.o
  CC	execve/enter.o
./execve/enter.c: In function 'extract_loader':
./execve/enter.c:529:2: warning: 'talloc_autofree_context' is deprecated [-Wdeprecated-declarations]
  529 |  loader_path = talloc_strdup(talloc_autofree_context(), path);
      |  ^~~~~~~~~~~
In file included from ./execve/enter.c:28:
/usr/include/talloc.h:1071:16: note: declared here
 1071 | _PUBLIC_ void *talloc_autofree_context(void) _DEPRECATED_;
      |                ^~~~~~~~~~~~~~~~~~~~~~~
  CC	execve/exit.o
  CC	execve/shebang.o
  CC	execve/elf.o
  CC	execve/ldso.o
  CC	execve/auxv.o
  CC	execve/aoxp.o
  CC	path/binding.o
  CC	path/glue.o
./path/glue.c: In function 'set_placeholder_destructor':
./path/glue.c:76:2: warning: 'talloc_autofree_context' is deprecated [-Wdeprecated-declarations]
   76 |  autofreed = talloc_autofree_context();
      |  ^~~~~~~~~
In file included from ./path/glue.c:31:
/usr/include/talloc.h:1071:16: note: declared here
 1071 | _PUBLIC_ void *talloc_autofree_context(void) _DEPRECATED_;
      |                ^~~~~~~~~~~~~~~~~~~~~~~
  CC	path/canon.o
In function 'next_component',
    inlined from 'canonicalize' at ./path/canon.c:229:14:
./path/canon.c:110:2: warning: 'strncpy' destination unchanged after copying no bytes [-Wstringop-truncation]
  110 |  strncpy(component, start, length);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC	path/path.o
  CC	path/proc.o
./path/proc.c: In function 'readlink_proc':
./path/proc.c:101:4: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
  101 |    strncpy(result, string, status + 1); \
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./path/proc.c:107:3: note: in expansion of macro 'SUBSTITUTE'
  107 |   SUBSTITUTE(exe, known_tracee->exe);
      |   ^~~~~~~~~~
./path/proc.c:97:13: note: length computed here
   97 |    status = strlen(string);  \
      |             ^~~~~~~~~~~~~~
./path/proc.c:107:3: note: in expansion of macro 'SUBSTITUTE'
  107 |   SUBSTITUTE(exe, known_tracee->exe);
      |   ^~~~~~~~~~
./path/proc.c:101:4: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
  101 |    strncpy(result, string, status + 1); \
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./path/proc.c:108:3: note: in expansion of macro 'SUBSTITUTE'
  108 |   SUBSTITUTE(cwd, known_tracee->fs->cwd);
      |   ^~~~~~~~~~
./path/proc.c:97:13: note: length computed here
   97 |    status = strlen(string);  \
      |             ^~~~~~~~~~~~~~
./path/proc.c:108:3: note: in expansion of macro 'SUBSTITUTE'
  108 |   SUBSTITUTE(cwd, known_tracee->fs->cwd);
      |   ^~~~~~~~~~
  CC	path/temp.o
./path/temp.c: In function 'get_temp_directory':
./path/temp.c:41:2: warning: 'talloc_autofree_context' is deprecated [-Wdeprecated-declarations]
   41 |  temp_directory = talloc_strdup(talloc_autofree_context(), tmp);
      |  ^~~~~~~~~~~~~~
In file included from ./path/temp.c:9:
/usr/include/talloc.h:1071:16: note: declared here
 1071 | _PUBLIC_ void *talloc_autofree_context(void) _DEPRECATED_;
      |                ^~~~~~~~~~~~~~~~~~~~~~~
./path/temp.c: In function 'create_temp_name':
./path/temp.c:287:3: warning: 'talloc_autofree_context' is deprecated [-Wdeprecated-declarations]
  287 |   context = talloc_autofree_context();
      |   ^~~~~~~
In file included from ./path/temp.c:9:
/usr/include/talloc.h:1071:16: note: declared here
 1071 | _PUBLIC_ void *talloc_autofree_context(void) _DEPRECATED_;
      |                ^~~~~~~~~~~~~~~~~~~~~~~
  CC	syscall/seccomp.o
  CC	syscall/syscall.o
  CC	syscall/chain.o
  CC	syscall/enter.o
  CC	syscall/exit.o
  CC	syscall/sysnum.o
  CC	syscall/socket.o
./syscall/socket.c: In function 'translate_socketcall_enter':
./syscall/socket.c:148:2: warning: 'strncpy' output may be truncated copying 108 bytes from a string of length 4095 [-Wstringop-truncation]
  148 |  strncpy(sockaddr.sun_path, host_path, sizeof_path);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC	syscall/heap.o
  CC	syscall/rlimit.o
In file included from ./syscall/rlimit.c:31:
./syscall/rlimit.c: In function 'translate_setrlimit_exit':
./cli/note.h:46:33: warning: format '%ld' expects argument of type 'long int', but argument 5 has type 'rlim_t' {aka 'long long unsigned int'} [-Wformat=]
   46 |    note(tracee, INFO, INTERNAL, (message), ## args); \
      |                                 ^~~~~~~~~
./syscall/rlimit.c:115:2: note: in expansion of macro 'VERBOSE'
  115 |  VERBOSE(tracee, 1, "stack soft limit increased to %ld bytes", proot_stack.rlim_cur);
      |  ^~~~~~~
  CC	tracee/tracee.o
  CC	tracee/mem.o
  CC	tracee/reg.o
  CC	tracee/event.o
  CC	ptrace/ptrace.o
  CC	ptrace/user.o
  CC	ptrace/wait.o
  CC	extension/extension.o
  CC	extension/kompat/kompat.o
  CC	extension/fake_id0/fake_id0.o
  CC	extension/link2symlink/link2symlink.o
./extension/link2symlink/link2symlink.c: In function 'decrement_link_count':
./extension/link2symlink/link2symlink.c:218:3: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
  218 |   strncpy(new_final, final, strlen(final) - 4);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./extension/link2symlink/link2symlink.c:218:29: note: length computed here
  218 |   strncpy(new_final, final, strlen(final) - 4);
      |                             ^~~~~~~~~~~~~
./extension/link2symlink/link2symlink.c: In function 'move_and_symlink_path':
./extension/link2symlink/link2symlink.c:139:3: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
  139 |   strncpy(new_final, final, strlen(final) - 4);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./extension/link2symlink/link2symlink.c:139:29: note: length computed here
  139 |   strncpy(new_final, final, strlen(final) - 4);
      |                             ^~~~~~~~~~~~~
  CC	extension/portmap/portmap.o
  CC	extension/portmap/map.o
  GEN	loader/loader-wrapped.o
  GEN	loader/loader-m32-wrapped.o
  CC	extension/python/python.o
  SWIG	proot_wrap.c
  CC	extension/python/proot_wrap.o
  GEN	extension/python/python_extension.o
  GEN	extension/python/proot.o
  LD	proot
rm python_extension.py
make: Leaving directory '/usr/src/proot/src'

[OrangeDog]

The cause appears to have been https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94391