Merge pull request #475 from brenoguim/breno.474

Use the largest segment alignment for libraries requiring non-standard alignments #474

Author: brenoguim

.github/workflows/publish.yml

@@ -89,7 +89,7 @@ jobs:
           rm -f dist/*
           cd patchelf-*
           ./configure --prefix /patchelf
-          make check
+          make check || (cat tests/test-suite.log; exit 1)
           make install-strip
           cd -
           tar -czf ./dist/patchelf-\$(cat patchelf-*/version)-\$(uname -m).tar.gz -C /patchelf .

src/patchelf.cc

@@ -800,12 +800,17 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsLibrary()
        page of other segments. */
     Elf_Addr startPage = 0;
     Elf_Addr firstPage = 0;
+    unsigned alignStartPage = getPageSize();
     for (auto & phdr : phdrs) {
-        Elf_Addr thisPage = roundUp(rdi(phdr.p_vaddr) + rdi(phdr.p_memsz), getPageSize());
+        Elf_Addr thisPage = rdi(phdr.p_vaddr) + rdi(phdr.p_memsz);
         if (thisPage > startPage) startPage = thisPage;
         if (rdi(phdr.p_type) == PT_PHDR) firstPage = rdi(phdr.p_vaddr) - rdi(phdr.p_offset);
+        unsigned thisAlign = rdi(phdr.p_align);
+        alignStartPage = std::max(alignStartPage, thisAlign);
     }
 
+    startPage = roundUp(startPage, alignStartPage);
+
     debug("last page is 0x%llx\n", (unsigned long long) startPage);
     debug("first page is 0x%llx\n", (unsigned long long) firstPage);
 
@@ -873,7 +878,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsLibrary()
     if (!phdrs.empty() &&
         rdi(lastSeg.p_type) == PT_LOAD &&
         rdi(lastSeg.p_flags) == (PF_R | PF_W) &&
-        rdi(lastSeg.p_align) == getPageSize()) {
+        rdi(lastSeg.p_align) == alignStartPage) {
         auto segEnd = roundUp(rdi(lastSeg.p_offset) + rdi(lastSeg.p_memsz), getPageSize());
         if (segEnd == startOffset) {
             auto newSz = startOffset + neededSpace - rdi(lastSeg.p_offset);
@@ -892,7 +897,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsLibrary()
         wri(phdr.p_vaddr, wri(phdr.p_paddr, startPage));
         wri(phdr.p_filesz, wri(phdr.p_memsz, neededSpace));
         wri(phdr.p_flags, PF_R | PF_W);
-        wri(phdr.p_align, getPageSize());
+        wri(phdr.p_align, alignStartPage);
     }
 
     normalizeNoteSegments();

tests/Makefile.am

@@ -119,7 +119,7 @@ check_DATA = libbig-dynstr.debug
 # - with libtool, it is difficult to control options
 # - with libtool, it is not possible to compile convenience *dynamic* libraries :-(
 check_PROGRAMS += libfoo.so libfoo-scoped.so libbar.so libbar-scoped.so libsimple.so libsimple-execstack.so libbuildid.so libtoomanystrtab.so \
-                  phdr-corruption.so many-syms-main libmany-syms.so
+                  phdr-corruption.so many-syms-main libmany-syms.so liboveralign.so
 
 libbuildid_so_SOURCES = simple.c
 libbuildid_so_LDFLAGS = $(LDFLAGS_sharedlib) -Wl,--build-id
@@ -143,6 +143,9 @@ libbar_scoped_so_LDFLAGS = $(LDFLAGS_sharedlib)
 libsimple_so_SOURCES = simple.c
 libsimple_so_LDFLAGS = $(LDFLAGS_sharedlib) -Wl,-z,noexecstack
 
+liboveralign_so_SOURCES = simple.c
+liboveralign_so_LDFLAGS = $(LDFLAGS_sharedlib) -Wl,-z,max-page-size=0x10000
+
 libsimple_execstack_so_SOURCES = simple.c
 libsimple_execstack_so_LDFLAGS = $(LDFLAGS_sharedlib) -Wl,-z,execstack
 

tests/set-rpath-library.sh

@@ -14,6 +14,7 @@ mkdir -p "${SCRATCH}/libsB"
 cp main-scoped "${SCRATCH}/"
 cp libfoo-scoped.so "${SCRATCH}/libsA/"
 cp libbar-scoped.so "${SCRATCH}/libsB/"
+cp liboveralign.so "${SCRATCH}/"
 
 oldRPath=$(../src/patchelf --print-rpath "${SCRATCH}"/main-scoped)
 if test -z "$oldRPath"; then oldRPath="/oops"; fi
@@ -56,3 +57,12 @@ if test "$exitCode" != 46; then
     echo "bad exit code!"
     exit 1
 fi
+
+# ALL loads should have the same alignment
+lib="${SCRATCH}/liboveralign.so"
+../src/patchelf --set-rpath "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" "$lib"
+num_alignments=$(${READELF} -W -l "${lib}"  | awk '/LOAD/ { print $NF }' | sort -u | wc -l)
+echo "$num_alignments"
+if test "${num_alignments}" -ne "1"; then
+    exit 1
+fi