Author: emaste Date: Sat Oct 13 21:26:07 2018 New Revision: 339350 URL: https://svnweb.freebsd.org/changeset/base/339350
Log: 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. PR: 232176 Reviewed by: kaiw, kib, markj Approved by: re (rgrimes) MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D17519 Modified: head/contrib/elftoolchain/elfcopy/sections.c Modified: head/contrib/elftoolchain/elfcopy/sections.c ============================================================================== --- head/contrib/elftoolchain/elfcopy/sections.c Sat Oct 13 21:18:31 2018 (r339349) +++ head/contrib/elftoolchain/elfcopy/sections.c Sat Oct 13 21:26:07 2018 (r339350) @@ -39,7 +39,6 @@ ELFTC_VCSID("$Id: sections.c 3443 2016-04-15 18:57:54Z static void add_gnu_debuglink(struct elfcopy *ecp); static uint32_t calc_crc32(const char *p, size_t len, uint32_t crc); static void check_section_rename(struct elfcopy *ecp, struct section *s); -static void filter_reloc(struct elfcopy *ecp, struct section *s); static int get_section_flags(struct elfcopy *ecp, const char *name); static void insert_sections(struct elfcopy *ecp); static void insert_to_strtab(struct section *t, const char *s); @@ -574,14 +573,6 @@ copy_content(struct elfcopy *ecp) continue; /* - * If strip action is STRIP_ALL, relocation info need - * to be stripped. Skip filtering otherwisw. - */ - if (ecp->strip == STRIP_ALL && - (s->type == SHT_REL || s->type == SHT_RELA)) - filter_reloc(ecp, s); - - /* * The section indices in the SHT_GROUP section needs * to be updated since we might have stripped some * sections and changed section numbering. @@ -670,125 +661,6 @@ update_section_group(struct elfcopy *ecp, struct secti s->sz -= 4; } - s->nocopy = 1; -} - -/* - * Filter relocation entries, only keep those entries whose - * symbol is in the keep list. - */ -static void -filter_reloc(struct elfcopy *ecp, struct section *s) -{ - const char *name; - GElf_Shdr ish; - GElf_Rel rel; - GElf_Rela rela; - Elf32_Rel *rel32; - Elf64_Rel *rel64; - Elf32_Rela *rela32; - Elf64_Rela *rela64; - Elf_Data *id; - uint64_t cap, n, nrels; - int elferr, i; - - if (gelf_getshdr(s->is, &ish) == NULL) - errx(EXIT_FAILURE, "gelf_getehdr() failed: %s", - elf_errmsg(-1)); - - /* We don't want to touch relocation info for dynamic symbols. */ - if ((ecp->flags & SYMTAB_EXIST) == 0) { - if (ish.sh_link == 0 || ecp->secndx[ish.sh_link] == 0) { - /* - * This reloc section applies to the symbol table - * that was stripped, so discard whole section. - */ - s->nocopy = 1; - s->sz = 0; - } - return; - } else { - /* Symbol table exist, check if index equals. */ - if (ish.sh_link != elf_ndxscn(ecp->symtab->is)) - return; - } - -#define COPYREL(REL, SZ) do { \ - if (nrels == 0) { \ - if ((REL##SZ = malloc(cap * \ - sizeof(*REL##SZ))) == NULL) \ - err(EXIT_FAILURE, "malloc failed"); \ - } \ - if (nrels >= cap) { \ - cap *= 2; \ - if ((REL##SZ = realloc(REL##SZ, cap * \ - sizeof(*REL##SZ))) == NULL) \ - err(EXIT_FAILURE, "realloc failed"); \ - } \ - REL##SZ[nrels].r_offset = REL.r_offset; \ - REL##SZ[nrels].r_info = REL.r_info; \ - if (s->type == SHT_RELA) \ - rela##SZ[nrels].r_addend = rela.r_addend; \ - nrels++; \ -} while (0) - - nrels = 0; - cap = 4; /* keep list is usually small. */ - rel32 = NULL; - rel64 = NULL; - rela32 = NULL; - rela64 = NULL; - if ((id = elf_getdata(s->is, NULL)) == NULL) - errx(EXIT_FAILURE, "elf_getdata() failed: %s", - elf_errmsg(-1)); - n = ish.sh_size / ish.sh_entsize; - for(i = 0; (uint64_t)i < n; i++) { - if (s->type == SHT_REL) { - if (gelf_getrel(id, i, &rel) != &rel) - errx(EXIT_FAILURE, "gelf_getrel failed: %s", - elf_errmsg(-1)); - } else { - if (gelf_getrela(id, i, &rela) != &rela) - errx(EXIT_FAILURE, "gelf_getrel failed: %s", - elf_errmsg(-1)); - } - name = elf_strptr(ecp->ein, elf_ndxscn(ecp->strtab->is), - GELF_R_SYM(rel.r_info)); - if (name == NULL) - errx(EXIT_FAILURE, "elf_strptr failed: %s", - elf_errmsg(-1)); - if (lookup_symop_list(ecp, name, SYMOP_KEEP) != NULL) { - if (ecp->oec == ELFCLASS32) { - if (s->type == SHT_REL) - COPYREL(rel, 32); - else - COPYREL(rela, 32); - } else { - if (s->type == SHT_REL) - COPYREL(rel, 64); - else - COPYREL(rela, 64); - } - } - } - elferr = elf_errno(); - if (elferr != 0) - errx(EXIT_FAILURE, "elf_getdata() failed: %s", - elf_errmsg(elferr)); - - if (ecp->oec == ELFCLASS32) { - if (s->type == SHT_REL) - s->buf = rel32; - else - s->buf = rela32; - } else { - if (s->type == SHT_REL) - s->buf = rel64; - else - s->buf = rela64; - } - s->sz = gelf_fsize(ecp->eout, (s->type == SHT_REL ? ELF_T_REL : - ELF_T_RELA), nrels, EV_CURRENT); s->nocopy = 1; } _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
