COPY relocs are fine to have in PIE executables (as opposed to shared libraries).
By enabling prelink on PIEs we achieve a few goals: - prelink more PIE files on system: nicer for uniformity, - avoid spurious warnings about shared libraries with COPY relocs It's usefult to prelink PIEs when kernel ASLR is disabled: kernel.randomize_va_space=0 + PIE-randomization patches. I have gcc built as `--enable-default-pie` (generates PIE executables by default). Testsute results before the change: PASS: 14 FAIL: 31 After the change: PASS: 32 FAIL: 13 Signed-off-by: Sergei Trofimovich <sly...@gentoo.org> --- src/arch-x86_64.c | 4 ++-- src/dso.c | 19 +++++++++++++++++++ src/prelink.h | 1 + 3 files changed, 22 insertions(+), 2 deletions(-) diff --git a/src/arch-x86_64.c b/src/arch-x86_64.c index 5c95f47..2f6c551 100644 --- a/src/arch-x86_64.c +++ b/src/arch-x86_64.c @@ -179,7 +179,7 @@ x86_64_prelink_rela (struct prelink_info *info, GElf_Rela *rela, value + rela->r_addend - info->resolvetls->offset); break; case R_X86_64_COPY: - if (dso->ehdr.e_type == ET_EXEC) + if (dso->ehdr.e_type == ET_EXEC || dso_is_pie(dso)) /* COPY relocs are handled specially in generic code. */ return 0; error (0, 0, "%s: R_X86_64_COPY reloc in shared library?", dso->filename); @@ -503,7 +503,7 @@ x86_64_undo_prelink_rela (DSO *dso, GElf_Rela *rela, GElf_Addr relaaddr) write_le32 (dso, rela->r_offset, 0); break; case R_X86_64_COPY: - if (dso->ehdr.e_type == ET_EXEC) + if (dso->ehdr.e_type == ET_EXEC || dso_is_pie(dso)) /* COPY relocs are handled specially in generic code. */ return 0; error (0, 0, "%s: R_X86_64_COPY reloc in shared library?", dso->filename); diff --git a/src/dso.c b/src/dso.c index a5fcec5..9fcfc3d 100644 --- a/src/dso.c +++ b/src/dso.c @@ -1106,6 +1106,25 @@ dso_is_rdwr (DSO *dso) return dso->elfro != NULL; } +/* Return true is DSO is position independent executable. + + There is no simple way to distinct between shared library + and PIE executable. Use presence of interpreter as a heuristic. */ + +int dso_is_pie(DSO *dso) +{ + int i; + + if (dso->ehdr.e_type != ET_DYN) + return 0; + + for (i = 0; i < dso->ehdr.e_phnum; ++i) + if (dso->phdr[i].p_type == PT_INTERP) + return 1; + + return 0; +} + GElf_Addr adjust_old_to_new (DSO *dso, GElf_Addr addr) { diff --git a/src/prelink.h b/src/prelink.h index 93dbf7a..d8a00c6 100644 --- a/src/prelink.h +++ b/src/prelink.h @@ -298,6 +298,7 @@ int reopen_dso (DSO *dso, struct section_move *move, const char *); int adjust_symbol_p (DSO *dso, GElf_Sym *sym); int check_dso (DSO *dso); int dso_is_rdwr (DSO *dso); +int dso_is_pie(DSO *dso); void read_dynamic (DSO *dso); int set_dynamic (DSO *dso, GElf_Word tag, GElf_Addr value, int fatal); int addr_to_sec (DSO *dso, GElf_Addr addr); -- 2.19.1 -- _______________________________________________ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto