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Allow multiple modifications in same call #361

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merged 6 commits into from
Dec 22, 2021
Merged

Allow multiple modifications in same call #361

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d306abe
Allow multiple modifications in same call
fzakaria Dec 21, 2021
e268662
Add a unit test
fzakaria Dec 21, 2021
dc375bc
Remove result and add it to gitignore
fzakaria Dec 21, 2021
d02a3ec
Code clarity and test working with musl
fzakaria Dec 21, 2021
e589fe3
Merge branch 'master' into faridzakaria/fix-add-replace-for-real
fzakaria Dec 21, 2021
b92a6e8
Fix replace-add-needed.sh test for musl
fzakaria Dec 21, 2021
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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -36,3 +36,4 @@ Makefile
.direnv/
.vscode/
.idea/
result
13 changes: 12 additions & 1 deletion src/patchelf.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1150,6 +1150,7 @@ void ElfFile<ElfFileParamNames>::modifySoname(sonameMode op, const std::string &
}

changed = true;
this->rewriteSections();
}

template<ElfFileParams>
Expand All @@ -1158,6 +1159,7 @@ void ElfFile<ElfFileParamNames>::setInterpreter(const std::string & newInterpret
std::string & section = replaceSection(".interp", newInterpreter.size() + 1);
setSubstr(section, 0, newInterpreter + '\0');
changed = true;
this->rewriteSections();
}


Expand Down Expand Up @@ -1234,6 +1236,7 @@ void ElfFile<ElfFileParamNames>::removeRPath(Elf_Shdr & shdrDynamic) {
}
}
memset(last, 0, sizeof(Elf_Dyn) * (dyn - last));
this->rewriteSections();
}

template<ElfFileParams>
Expand Down Expand Up @@ -1380,6 +1383,7 @@ void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op,
newDyn.d_un.d_val = shdrDynStr.sh_size;
setSubstr(newDynamic, 0, std::string((char *) &newDyn, sizeof(Elf_Dyn)));
}
this->rewriteSections();
}


Expand Down Expand Up @@ -1409,6 +1413,8 @@ void ElfFile<ElfFileParamNames>::removeNeeded(const std::set<std::string> & libs
}

memset(last, 0, sizeof(Elf_Dyn) * (dyn - last));

this->rewriteSections();
}

template<ElfFileParams>
Expand Down Expand Up @@ -1532,6 +1538,8 @@ void ElfFile<ElfFileParamNames>::replaceNeeded(const std::map<std::string, std::
--verNeedNum;
}
}

this->rewriteSections();
}

template<ElfFileParams>
Expand Down Expand Up @@ -1582,6 +1590,8 @@ void ElfFile<ElfFileParamNames>::addNeeded(const std::set<std::string> & libs)
}

changed = true;

this->rewriteSections();
}

template<ElfFileParams>
Expand Down Expand Up @@ -1638,6 +1648,7 @@ void ElfFile<ElfFileParamNames>::noDefaultLib()
setSubstr(newDynamic, 0, std::string((char *) &newDyn, sizeof(Elf_Dyn)));
}

this->rewriteSections();
changed = true;
}

Expand Down Expand Up @@ -1667,6 +1678,7 @@ void ElfFile<ElfFileParamNames>::clearSymbolVersions(const std::set<std::string>
}
}
changed = true;
this->rewriteSections();
}

static bool printInterpreter = false;
Expand Down Expand Up @@ -1726,7 +1738,6 @@ static void patchElf2(ElfFile && elfFile, const FileContents & fileContents, con
elfFile.noDefaultLib();
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if (elfFile.isChanged()){
elfFile.rewriteSections();
writeFile(fileName, elfFile.fileContents);
} else if (alwaysWrite) {
debug("not modified, but alwaysWrite=true\n");
Expand Down
3 changes: 2 additions & 1 deletion tests/Makefile.am
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Expand Up @@ -39,7 +39,8 @@ src_TESTS = \
basic-flags.sh \
set-empty-rpath.sh \
phdr-corruption.sh \
replace-needed.sh
replace-needed.sh \
replace-add-needed.sh

build_TESTS = \
$(no_rpath_arch_TESTS)
Expand Down
38 changes: 38 additions & 0 deletions tests/replace-add-needed.sh
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@@ -0,0 +1,38 @@
#! /bin/sh -e
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SCRATCH=scratch/$(basename $0 .sh)
PATCHELF=$(readlink -f "../src/patchelf")

rm -rf ${SCRATCH}
mkdir -p ${SCRATCH}

cp simple ${SCRATCH}/
cp libfoo.so ${SCRATCH}/
cp libbar.so ${SCRATCH}/

cd ${SCRATCH}

libcldd=$(ldd ./simple | awk '/ => / { print $3 }' | grep -E "(libc.so|ld-musl)")

# We have to set the soname on these libraries
${PATCHELF} --set-soname libbar.so ./libbar.so
Comment on lines +16 to +17
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Interestingly discussed with @trws that if the shared object doesn't have a DT_SONAME, it won't make use of the previously discovered loaded shared object.

This was discovered while writing this test. You can see below that libbar.so was not found, even though its set with an absolute path.

ldd ~/code/github.com/NixOS/patchelf/tests/scratch/replace-add-needed/simple
	linux-vdso.so.1 (0x00007ffc90565000)
	/home/fmzakari/code/github.com/NixOS/patchelf/tests/scratch/replace-add-needed/libbar.so (0x00007f532a4c4000)
	/home/fmzakari/code/github.com/NixOS/patchelf/tests/scratch/replace-add-needed/libfoo.so (0x00007f532a4bf000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f532a2da000)
	/nix/store/jsp3h3wpzc842j0rz61m5ly71ak6qgdn-glibc-2.32-54/lib/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 (0x00007f532a4cb000)
	libbar.so => not found


# Add a libbar.so so we can rewrite it later
${PATCHELF} --add-needed libbar.so ./simple

# Make the NEEDED in libfoo the same as simple
# This is a current "bug" in musl
# https://www.openwall.com/lists/musl/2021/12/21/1
${PATCHELF} --replace-needed libbar.so $(readlink -f ./libbar.so) ./libfoo.so
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@Mic92 please read the linked mailing issue I opened for why we have to do this for musl
https://www.openwall.com/lists/musl/2021/12/21/1

This should now succeed on musl and glibc proving the fix of the bug.


${PATCHELF} --replace-needed libc.so.6 ${libcldd} \
--replace-needed libbar.so $(readlink -f ./libbar.so) \
--add-needed $(readlink -f ./libfoo.so) \
./simple

exitCode=0
./simple || exitCode=$?

if test "$exitCode" != 0; then
ldd ./simple
exit 1
fi