Merge 914043a into 67d49a6

CHANGELOG.md

@@ -96,13 +96,15 @@ The table below shows which release corresponds to each branch, and what date th
 - [#1981][1981] Fix `cyclic_find()` to make it work with large int values
 - [#2123][2123] Fix ROP without a writeable cache directory
 - [#2124][2124] Fix `tube.recvpred()` timout argument
+- [#2141][2141] Fix `make_elf` on systems with GNU ld 2.39+
 
 [1922]: https://github.com/Gallopsled/pwntools/pull/1922
 [1828]: https://github.com/Gallopsled/pwntools/pull/1828
 [1939]: https://github.com/Gallopsled/pwntools/pull/1939
 [1981]: https://github.com/Gallopsled/pwntools/pull/1981
 [2123]: https://github.com/Gallopsled/pwntools/pull/2123
 [2124]: https://github.com/Gallopsled/pwntools/pull/2124
+[2141]: https://github.com/Gallopsled/pwntools/pull/2141
 
 ## 4.7.1
 

pwnlib/asm.py

@@ -276,6 +276,21 @@ def _linker():
         'i386': ['-m', 'elf_i386'],
     }.get(context.arch, [])
 
+    try:
+        with context.local(log_level='critical'):
+            version = _run(ld + ["-v"])
+        if "GNU ld (GNU Binutils)" in version:
+            number = version.split()[4]
+            major, minor, _ = [int(n) for n in number.split(".")]
+            # https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob_plain;f=ld/NEWS;hb=refs/heads/binutils-2_39-branch
+            # GNU ld 2.39+ will warn on RWX segments in an ELF
+            if (major == 2 and minor >= 39) or major > 2:
+                arguments.append("--no-warn-rwx-segments")
+    except Exception:
+        # If the output format is wrong or `ld -v` errors, just ignore it
+        # and (maybe) fail later
+        pass
+
     return ld + bfd + [E] + arguments
 
 def _objcopy():
@@ -570,7 +585,8 @@ def make_elf(data,
         log.error("Cannot specify a VMA for a shared library.")
 
     if context.arch == 'thumb':
-        to_thumb = asm(shellcraft.arm.to_thumb(), arch='arm')
+        with context.local(arch='arm'):
+            to_thumb = asm(shellcraft.arm.to_thumb())
 
         if not data.startswith(to_thumb):
             data = to_thumb + data