Date: Thu, 25 Oct 2018 13:46:47 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 232176] elftoolchain elfcopy/strip incorrectly strips relocations Message-ID: <bug-232176-227-vFchikoJsQ@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-232176-227@https.bugs.freebsd.org/bugzilla/> References: <bug-232176-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D232176 --- Comment #6 from commit-hook@freebsd.org --- A commit references this bug: Author: emaste Date: Thu Oct 25 13:46:28 UTC 2018 New revision: 339710 URL: https://svnweb.freebsd.org/changeset/base/339710 Log: elfcopy: avoid stripping relocations from static binaries MFC r339350: elfcopy: delete filter_reloc, it is broken and unnecessary elfcopy contained logic to filter individual relocations in STRIP_ALL mode. However, this is not valid; relocations emitted by the linker are required, unless they apply to an entire section being removed (which is handled by other logic in elfcopy). Note that filter_reloc was also buggy: for RELA relocation sections it operated on uninitialized rel.r_info resulting in invalid operation. The logic most likely needs to be inverted: instead of removing relocations because their associated symbols are being removed, we must keep symbols referenced by relocations. That said, in practice we do not encounter this code path today: objects being stripped are either dynamically linked binaries which retain .dynsym, or static binaries with no relocations. Just remove filter_reloc. This fixes certain cases including statically linked binaries containing ifuncs. Stripping binaries with relocations referencing removed symbols was already broken, and after this change may still be broken in a different way. MFC r339451: objcopy: restore behaviour required by GCC's build In r339350 filter_reloc() was removed, to fix the case of stripping statically linked binaries with relocations (which may come from ifunc use, for example). As a side effect this changed the behaviour when stripping object files - the output was broken both before and after r339350, in different ways. Unfortunately GCC's build process relies on the previous behaviour, so: - Revert r339350, restoring filter_reloc(). - Fix an unitialized variable use (commited as r3638 in ELF Tool Chain). - Change filter_reloc() to omit relocations referencing removed symbols, while retaining relocations with no symbol reference. - Retain the entire relocation section if it references the dynamic symbol table (fix from kaiw in D17596). PR: 232176 Sponsored by: The FreeBSD Foundation Changes: _U stable/11/ stable/11/contrib/elftoolchain/elfcopy/sections.c --=20 You are receiving this mail because: You are the assignee for the bug.=
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