From 5474d94f03aedba2f832006dc7d680cc15792a7b Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Mon, 26 Dec 2016 00:30:45 +1030 Subject: dynrelro section for read-only dynamic symbols copied into executable Variables defined in shared libraries are copied into an executable's .bss section when code in the executable is non-PIC and thus would require dynamic text relocations to access the variable directly in the shared library. Recent x86 toolchains also copy variables into the executable to gain a small speed improvement. The problem is that if the variable was originally read-only, the copy in .bss is writable, potentially opening a security hole. This patch cures that problem by putting the copy in a section that becomes read-only after ld.so relocation, provided -z relro is in force. The patch also fixes a microblaze linker segfault on attempting to use dynamic bss variables. bfd/ PR ld/20995 * elf-bfd.h (struct elf_link_hash_table): Add sdynrelro and sreldynrelro. (struct elf_backend_data): Add want_dynrelro. * elfxx-target.h (elf_backend_want_dynrelro): Define. (elfNN_bed): Update initializer. * elflink.c (_bfd_elf_create_dynamic_sections): Create sdynrelro and sreldynrelro sections. * elf32-arm.c (elf32_arm_adjust_dynamic_symbol): Place variables copied into the executable from read-only sections into sdynrelro. (elf32_arm_size_dynamic_sections): Handle sdynrelro. (elf32_arm_finish_dynamic_symbol): Select sreldynrelro for dynamic relocs in sdynrelro. (elf_backend_want_dynrelro): Define. * elf32-hppa.c (elf32_hppa_adjust_dynamic_symbol) (elf32_hppa_size_dynamic_sections, elf32_hppa_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-i386.c (elf_i386_adjust_dynamic_symbol) (elf_i386_size_dynamic_sections, elf_i386_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-metag.c (elf_metag_adjust_dynamic_symbol) (elf_metag_size_dynamic_sections, elf_metag_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-microblaze.c (microblaze_elf_adjust_dynamic_symbol) (microblaze_elf_size_dynamic_sections) (microblaze_elf_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-nios2.c (nios2_elf32_finish_dynamic_symbol) (nios2_elf32_adjust_dynamic_symbol) (nios2_elf32_size_dynamic_sections) (elf_backend_want_dynrelro): As above. * elf32-or1k.c (or1k_elf_finish_dynamic_symbol) (or1k_elf_adjust_dynamic_symbol, or1k_elf_size_dynamic_sections) (elf_backend_want_dynrelro): As above. * elf32-ppc.c (ppc_elf_adjust_dynamic_symbol) (ppc_elf_size_dynamic_sections, ppc_elf_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-s390.c (elf_s390_adjust_dynamic_symbol) (elf_s390_size_dynamic_sections, elf_s390_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-tic6x.c (elf32_tic6x_adjust_dynamic_symbol) (elf32_tic6x_size_dynamic_sections) (elf32_tic6x_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf32-tilepro.c (tilepro_elf_adjust_dynamic_symbol) (tilepro_elf_size_dynamic_sections) (tilepro_elf_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf64-ppc.c (ppc64_elf_adjust_dynamic_symbol) (ppc64_elf_size_dynamic_sections, ppc64_elf_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf64-s390.c (elf_s390_adjust_dynamic_symbol) (elf_s390_size_dynamic_sections, elf_s390_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elf64-x86-64.c (elf_x86_64_adjust_dynamic_symbol) (elf_x86_64_size_dynamic_sections) (elf_x86_64_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elfnn-aarch64.c (elfNN_aarch64_adjust_dynamic_symbol) (elfNN_aarch64_size_dynamic_sections) (elfNN_aarch64_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elfnn-riscv.c (riscv_elf_adjust_dynamic_symbol) (riscv_elf_size_dynamic_sections, riscv_elf_finish_dynamic_symbol) (elf_backend_want_dynrelro): As above. * elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol) (_bfd_mips_elf_size_dynamic_sections) (_bfd_mips_vxworks_finish_dynamic_symbol): As above. * elfxx-sparc.c (_bfd_sparc_elf_adjust_dynamic_symbol) (_bfd_sparc_elf_size_dynamic_sections) (_bfd_sparc_elf_finish_dynamic_symbol): As above. * elfxx-tilegx.c (tilegx_elf_adjust_dynamic_symbol) (tilegx_elf_size_dynamic_sections) (tilegx_elf_finish_dynamic_symbol): As above. * elf32-mips.c (elf_backend_want_dynrelro): Define. * elf64-mips.c (elf_backend_want_dynrelro): Define. * elf32-sparc.c (elf_backend_want_dynrelro): Define. * elf64-sparc.c (elf_backend_want_dynrelro): Define. * elf32-tilegx.c (elf_backend_want_dynrelro): Define. * elf64-tilegx.c (elf_backend_want_dynrelro): Define. * elf32-microblaze.c (microblaze_elf_adjust_dynamic_symbol): Tidy. (microblaze_elf_size_dynamic_sections): Handle sdynbss. * elf32-nios2.c (nios2_elf32_size_dynamic_sections): Make use of linker shortcuts to dynamic sections rather than comparing names. Correctly set "got" flag. ld/ PR ld/20995 * testsuite/ld-arm/farcall-mixed-app-v5.d: Update to suit changed stub hash table traversal caused by section id increment. Accept the previous output too. * testsuite/ld-arm/farcall-mixed-app.d: Likewise. * testsuite/ld-arm/farcall-mixed-lib-v4t.d: Likewise. * testsuite/ld-arm/farcall-mixed-lib.d: Likewise. * testsuite/ld-elf/pr20995a.s, * testsuite/ld-elf/pr20995b.s, * testsuite/ld-elf/pr20995.r: New test. * testsuite/ld-elf/elf.exp: Run it. --- ld/ChangeLog | 13 +++++++++++++ ld/testsuite/ld-arm/farcall-mixed-app-v5.d | 16 ++++++++-------- ld/testsuite/ld-arm/farcall-mixed-app.d | 16 ++++++++-------- ld/testsuite/ld-arm/farcall-mixed-lib-v4t.d | 16 ++++++++-------- ld/testsuite/ld-arm/farcall-mixed-lib.d | 16 ++++++++-------- ld/testsuite/ld-elf/elf.exp | 14 ++++++++++++++ ld/testsuite/ld-elf/pr20995.r | 5 +++++ ld/testsuite/ld-elf/pr20995a.s | 11 +++++++++++ ld/testsuite/ld-elf/pr20995b.s | 13 +++++++++++++ 9 files changed, 88 insertions(+), 32 deletions(-) create mode 100644 ld/testsuite/ld-elf/pr20995.r create mode 100644 ld/testsuite/ld-elf/pr20995a.s create mode 100644 ld/testsuite/ld-elf/pr20995b.s (limited to 'ld') diff --git a/ld/ChangeLog b/ld/ChangeLog index a9f157e..1b8f59a 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,5 +1,18 @@ 2016-12-26 Alan Modra + PR ld/20995 + * testsuite/ld-arm/farcall-mixed-app-v5.d: Update to suit changed + stub hash table traversal caused by section id increment. Accept + the previous output too. + * testsuite/ld-arm/farcall-mixed-app.d: Likewise. + * testsuite/ld-arm/farcall-mixed-lib-v4t.d: Likewise. + * testsuite/ld-arm/farcall-mixed-lib.d: Likewise. + * testsuite/ld-elf/pr20995a.s, * testsuite/ld-elf/pr20995b.s, + * testsuite/ld-elf/pr20995.r: New test. + * testsuite/ld-elf/elf.exp: Run it. + +2016-12-26 Alan Modra + * scripttempl/elf.sc: Don't use $BSS_NAME in .dynbss. 2016-12-23 Tristan Gingold diff --git a/ld/testsuite/ld-arm/farcall-mixed-app-v5.d b/ld/testsuite/ld-arm/farcall-mixed-app-v5.d index b570bad..af44198 100644 --- a/ld/testsuite/ld-arm/farcall-mixed-app-v5.d +++ b/ld/testsuite/ld-arm/farcall-mixed-app-v5.d @@ -50,8 +50,8 @@ Disassembly of section .far_arm: .* : .*: e1a0c00d mov ip, sp .*: e92dd800 push {fp, ip, lr, pc} - .*: eb0000.. bl .* <__lib_func1_veneer> - .*: eb0000.. bl .* <__lib_func2_veneer> + .*: eb00000(6|8) bl .* <__lib_func1_veneer> + .*: eb00000(7|5) bl .* <__lib_func2_veneer> .*: e89d6800 ldm sp, {fp, sp, lr} .*: e12fff1e bx lr .*: e1a00000 nop ; \(mov r0, r0\) @@ -61,12 +61,12 @@ Disassembly of section .far_arm: .*: e12fff1e bx lr #... -.* <__lib_func1_veneer>: - .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func1_veneer\+0x4> - .*: 000081e8 .word 0x000081e8 -.* <__lib_func2_veneer>: - .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func2_veneer\+0x4> - .*: 000081dc .word 0x000081dc +.* <__lib_func(1|2)_veneer>: + .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func(1|2)_veneer\+0x4> + .*: 000081(e8|dc) .word 0x000081(e8|dc) +.* <__lib_func(2|1)_veneer>: + .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func(2|1)_veneer\+0x4> + .*: 000081(dc|e8) .word 0x000081(dc|e8) Disassembly of section .far_thumb: diff --git a/ld/testsuite/ld-arm/farcall-mixed-app.d b/ld/testsuite/ld-arm/farcall-mixed-app.d index 9fa97dc..f3be54f 100644 --- a/ld/testsuite/ld-arm/farcall-mixed-app.d +++ b/ld/testsuite/ld-arm/farcall-mixed-app.d @@ -52,8 +52,8 @@ Disassembly of section .far_arm: .* : .*: e1a0c00d mov ip, sp .*: e92dd800 push {fp, ip, lr, pc} - .*: eb000006 bl .* <__lib_func1_veneer> - .*: eb000007 bl .* <__lib_func2_veneer> + .*: eb00000(6|8) bl .* <__lib_func1_veneer> + .*: eb00000(7|5) bl .* <__lib_func2_veneer> .*: e89d6800 ldm sp, {fp, sp, lr} .*: e12fff1e bx lr .*: e1a00000 nop ; \(mov r0, r0\) @@ -63,12 +63,12 @@ Disassembly of section .far_arm: .*: e12fff1e bx lr #... -.* <__lib_func1_veneer>: - .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func1_veneer\+0x4> - .*: 000081ec .word 0x000081ec -.* <__lib_func2_veneer>: - .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func2_veneer\+0x4> - .*: 000081e0 .word 0x000081e0 +.* <__lib_func(1|2)_veneer>: + .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func(1|2)_veneer\+0x4> + .*: 000081e(c|0) .word 0x000081e(c|0) +.* <__lib_func(2|1)_veneer>: + .*: e51ff004 ldr pc, \[pc, #-4\] ; .* <__lib_func(2|1)_veneer\+0x4> + .*: 000081e(0|c) .word 0x000081e(0|c) Disassembly of section .far_thumb: diff --git a/ld/testsuite/ld-arm/farcall-mixed-lib-v4t.d b/ld/testsuite/ld-arm/farcall-mixed-lib-v4t.d index fa52ad1..83b15a0 100644 --- a/ld/testsuite/ld-arm/farcall-mixed-lib-v4t.d +++ b/ld/testsuite/ld-arm/farcall-mixed-lib-v4t.d @@ -87,24 +87,24 @@ Disassembly of section .text: ... .* <__real_lib_func3>: - .*: f000 f80e bl 2000390 <__app_func_from_thumb> - .*: f000 f804 bl 2000380 <__app_func_weak_from_thumb> + .*: f000 f80(e|6) bl .* <__app_func_from_thumb> + .*: f000 f80(4|c) bl .* <__app_func_weak_from_thumb> .*: 4770 bx lr #... -.* <__app_func_weak_from_thumb>: +.* <__app_func(_weak)?_from_thumb>: .*: 4778 bx pc .*: 46c0 nop ; \(mov r8, r8\) - .*: e59fc000 ldr ip, \[pc\] ; 200038c <__app_func_weak_from_thumb\+0xc> + .*: e59fc000 ldr ip, \[pc\] ; 200038c <__app_func(_weak)?_from_thumb\+0xc> .*: e08cf00f add pc, ip, pc - .*: fdffff28 .word 0xfdffff28 + .*: fdffff(2|1)8 .word 0xfdffff(2|1)8 -.* <__app_func_from_thumb>: +.* <__app_func(_weak)?_from_thumb>: .*: 4778 bx pc .*: 46c0 nop ; \(mov r8, r8\) - .*: e59fc000 ldr ip, \[pc\] ; 200039c <__app_func_from_thumb\+0xc> + .*: e59fc000 ldr ip, \[pc\] ; 200039c <__app_func(_weak)?_from_thumb\+0xc> .*: e08cf00f add pc, ip, pc - .*: fdffff08 .word 0xfdffff08 + .*: fdffff(0|1)8 .word 0xfdffff(0|1)8 .* : .*: e59fc004 ldr ip, \[pc, #4\] ; 20003ac diff --git a/ld/testsuite/ld-arm/farcall-mixed-lib.d b/ld/testsuite/ld-arm/farcall-mixed-lib.d index ad7352b..d256477 100644 --- a/ld/testsuite/ld-arm/farcall-mixed-lib.d +++ b/ld/testsuite/ld-arm/farcall-mixed-lib.d @@ -72,18 +72,18 @@ Disassembly of section .text: ... .* : - .*: f000 e80c blx 200037c <__app_func_from_thumb> - .*: f000 e804 blx 2000370 <__app_func_weak_from_thumb> + .*: f000 e80(c|6) blx .* <__app_func_from_thumb> + .*: f000 e80(4|a) blx .* <__app_func_weak_from_thumb> .*: 4770 bx lr #... -.* <__app_func_weak_from_thumb>: - .*: e59fc000 ldr ip, \[pc\] ; 2000378 <__app_func_weak_from_thumb\+0x8> +.* <__app_func(_weak)?_from_thumb>: + .*: e59fc000 ldr ip, \[pc\] ; 2000378 <__app_func(_weak)?_from_thumb\+0x8> .*: e08ff00c add pc, pc, ip - .*: fdffff34 .word 0xfdffff34 + .*: fdffff(34|28) .word 0xfdffff(34|28) -.* <__app_func_from_thumb>: - .*: e59fc000 ldr ip, \[pc\] ; 2000384 <__app_func_from_thumb\+0x8> +.* <__app_func(_weak)?_from_thumb>: + .*: e59fc000 ldr ip, \[pc\] ; 2000384 <__app_func(_weak)?_from_thumb\+0x8> .*: e08ff00c add pc, pc, ip - .*: fdffff1c .word 0xfdffff1c + .*: fdffff(1c|28) .word 0xfdffff(1c|28) ... diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp index f93ad46..9b1fbeb 100644 --- a/ld/testsuite/ld-elf/elf.exp +++ b/ld/testsuite/ld-elf/elf.exp @@ -127,6 +127,20 @@ if { [check_shared_lib_support] } then { {symbolic-func.s} {{readelf {-r --wide} symbolic-func.r}} "symbolic-func.so"} } + # xfail on tic6x due to non-PIC/non-PID warnings + setup_xfail "tic6x-*-*" + run_ld_link_tests { + {"Build pr20995.so" + "-shared" "" "" + {pr20995b.s} {} "pr20995.so"} + } + # These targets don't copy dynamic variables into .bss. + setup_xfail "alpha-*-*" "bfin-*-*" "ia64-*-*" "xtensa-*-*" + run_ld_link_tests { + {"pr20995" + "" "tmpdir/pr20995.so" "" + {pr20995a.s} {{readelf {-S --wide} pr20995.r}} "pr20995"} + } } set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]] diff --git a/ld/testsuite/ld-elf/pr20995.r b/ld/testsuite/ld-elf/pr20995.r new file mode 100644 index 0000000..7336de6 --- /dev/null +++ b/ld/testsuite/ld-elf/pr20995.r @@ -0,0 +1,5 @@ +#... +.* \.data\.rel\.ro +PROGBITS +[^ ]+ [^ ]+ [^ ]*[1-9a-f]0* .* +#... +.* \.bss +NOBITS +[^ ]+ [^ ]+ [^ ]*[1-9a-f]0* .* +#... diff --git a/ld/testsuite/ld-elf/pr20995a.s b/ld/testsuite/ld-elf/pr20995a.s new file mode 100644 index 0000000..8da589c --- /dev/null +++ b/ld/testsuite/ld-elf/pr20995a.s @@ -0,0 +1,11 @@ + .text + .global start +start: + .global _start +_start: + .global __start +__start: + .global main +main: + .dc.a rw + .dc.a ro diff --git a/ld/testsuite/ld-elf/pr20995b.s b/ld/testsuite/ld-elf/pr20995b.s new file mode 100644 index 0000000..7ff76ee --- /dev/null +++ b/ld/testsuite/ld-elf/pr20995b.s @@ -0,0 +1,13 @@ + .data + .type rw,%object + .globl rw +rw: + .dc.a 0 + .size rw, . - rw + + .text + .type ro,%object + .globl ro +ro: + .dc.a 0 + .size ro, . - ro -- cgit v1.1