Date: Thu, 11 Oct 2018 12:57:04 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 232176] elftoolchain elfcopy/strip incorrectly strips relocations Message-ID: <bug-232176-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D232176 Bug ID: 232176 Summary: elftoolchain elfcopy/strip incorrectly strips relocations Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: emaste@freebsd.org Blocks: 231882 When using ifuncs in static binaries we'll have R_X86_64_IRELATIVE relocati= ons in .rela.plt: nuc% readelf -r ifunc_reproducer/make.full=20 Relocation section with addend (.rela.plt): r_offset r_info r_type st_value st_name + r_addend 0000002edaa0 000000000025 R_X86_64_IRELATIVE 0000000000000000 + 2e91f0 Relevant sections: % readelf -S ifunc_reproducer/make.full=20 There are 36 section headers, starting at offset 0x434420: Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align [ 0] NULL 0000000000000000 00000000 0000000000000000 0000000000000000 0 0 0 [ 3] .rela.plt RELA 00000000002181a0 000181a0 0000000000000018 0000000000000018 A 33 11 8 [ 9] .plt PROGBITS 00000000002e9c20 000e9c20 0000000000000010 0000000000000000 AX 0 0 16 [11] .got.plt PROGBITS 00000000002edaa0 000edaa0 0000000000000008 0000000000000000 WA 0 0 8 [33] .symtab SYMTAB 0000000000000000 004148f8 0000000000012d38 0000000000000018 35 1582 8 [34] .shstrtab STRTAB 0000000000000000 00427630 000000000000016f 0000000000000000 0 0 1 [35] .strtab STRTAB 0000000000000000 0042779f 000000000000cc7b 0000000000000000 0 0 1 Stripping with objcopy: % objcopy --strip-all ifunc_reproducer/make.full make.stripped results in a broken binary: % ./make.stripped <jemalloc>: jemalloc_arena.c:230: Failed assertion: "!bitmap_full(slab_data->bitmap, &bin_info->bitmap_info)" zsh: abort (core dumped) ./make.stripped because the relocation has been removed: % readelf -r make.stripped Relocation section with addend (.rela.plt): r_offset r_info r_type st_value st_name + r_addend Due to this snippet in elfcopy/sections.c::filter_reloc() /* We don't want to touch relocation info for dynamic symbols. */ if ((ecp->flags & SYMTAB_EXIST) =3D=3D 0) { if (ish.sh_link =3D=3D 0 || ecp->secndx[ish.sh_link] =3D=3D= 0) { /* * This reloc section applies to the symbol table * that was stripped, so discard whole section. */ s->nocopy =3D 1; s->sz =3D 0; } return; This is invalid - we can remove the reloc section if the section to which it refers is being stripped, as in create_scn(): if (ish.sh_type =3D=3D SHT_REL || ish.sh_type =3D=3D SHT_RE= LA) if (ish.sh_info !=3D 0 && is_remove_reloc_sec(ecp, ish.sh_info)) continue; but removing based on the string table results in broken output. Referenced Bugs: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D231882 [Bug 231882] multiple toolchain issues with statically linked binaries --=20 You are receiving this mail because: You are the assignee for the bug.=
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