From 8efa2874ab298f3923f4127340da119435f87c39 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 13 Aug 2015 04:31:38 -0700 Subject: [PATCH] Issue an error for read-only segment with dynamic IFUNC relocations To load an ELF binary with DT_TEXTREL tag, the dynamic linker calls __mprotect on the read-only segment with PROT_READ|PROT_WRITE before applying dynamic relocation. It leads to segfault when performing IFUNC relocations since the read-only segment has no execute permission. This patch changes x86 linker to issue an error for read-only segment with dynamic IFUNC relocations. Other backends with IFUNC support may need a similar change. bfd/ PR ld/18801 * elf32-i386.c (elf_i386_size_dynamic_sections): Issue an error for read-only segment with dynamic IFUNC relocations. * elf64-x86-64.c (elf_x86_64_size_dynamic_sections): Likewise. ld/testsuite/ PR ld/18801 * ld-i386/i386.exp: Run pr18801. * ld-x86-64/x86-64.exp: Likewise. * ld-i386/pr18801.d: New file. * ld-i386/pr18801.s: Likewise. * ld-x86-64/pr18801.d: Likewise. * ld-x86-64/pr18801.s: Likewise. --- bfd/ChangeLog | 7 +++++++ bfd/elf32-i386.c | 9 +++++++++ bfd/elf64-x86-64.c | 9 +++++++++ ld/testsuite/ChangeLog | 10 ++++++++++ ld/testsuite/ld-i386/i386.exp | 1 + ld/testsuite/ld-i386/pr18801.d | 3 +++ ld/testsuite/ld-i386/pr18801.s | 15 +++++++++++++++ ld/testsuite/ld-x86-64/pr18801.d | 3 +++ ld/testsuite/ld-x86-64/pr18801.s | 15 +++++++++++++++ ld/testsuite/ld-x86-64/x86-64.exp | 1 + 10 files changed, 73 insertions(+) create mode 100644 ld/testsuite/ld-i386/pr18801.d create mode 100644 ld/testsuite/ld-i386/pr18801.s create mode 100644 ld/testsuite/ld-x86-64/pr18801.d create mode 100644 ld/testsuite/ld-x86-64/pr18801.s diff --git a/bfd/ChangeLog b/bfd/ChangeLog index e561764446..9ba5902739 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,10 @@ +2015-08-13 H.J. Lu + + PR ld/18801 + * elf32-i386.c (elf_i386_size_dynamic_sections): Issue an error + for read-only segment with dynamic IFUNC relocations. + * elf64-x86-64.c (elf_x86_64_size_dynamic_sections): Likewise. + 2015-08-12 Simon Dardis * elfxx-mips.c (STUB_MOVE): Change to use 'or' only. diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index 3063bed7d1..1e4c3f4718 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -3152,6 +3152,15 @@ elf_i386_size_dynamic_sections (bfd *output_bfd, struct bfd_link_info *info) if ((info->flags & DF_TEXTREL) != 0) { + if ((elf_tdata (output_bfd)->has_gnu_symbols + & elf_gnu_symbol_ifunc) == elf_gnu_symbol_ifunc) + { + info->callbacks->einfo + (_("%P%X: read-only segment has dynamic IFUNC relocations; recompile with -fPIC\n")); + bfd_set_error (bfd_error_bad_value); + return FALSE; + } + if (!add_dynamic_entry (DT_TEXTREL, 0)) return FALSE; } diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index 2d3c55ea81..348b297d8f 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -3513,6 +3513,15 @@ elf_x86_64_size_dynamic_sections (bfd *output_bfd, if ((info->flags & DF_TEXTREL) != 0) { + if ((elf_tdata (output_bfd)->has_gnu_symbols + & elf_gnu_symbol_ifunc) == elf_gnu_symbol_ifunc) + { + info->callbacks->einfo + (_("%P%X: read-only segment has dynamic IFUNC relocations; recompile with -fPIC\n")); + bfd_set_error (bfd_error_bad_value); + return FALSE; + } + if (!add_dynamic_entry (DT_TEXTREL, 0)) return FALSE; } diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog index a38dc8bb3f..5ae5cd46fe 100644 --- a/ld/testsuite/ChangeLog +++ b/ld/testsuite/ChangeLog @@ -1,3 +1,13 @@ +2015-08-13 H.J. Lu + + PR ld/18801 + * ld-i386/i386.exp: Run pr18801. + * ld-x86-64/x86-64.exp: Likewise. + * ld-i386/pr18801.d: New file. + * ld-i386/pr18801.s: Likewise. + * ld-x86-64/pr18801.d: Likewise. + * ld-x86-64/pr18801.s: Likewise. + 2015-08-12 Simon Dardis * ld-mips-elf/compressed-plt-1-n32-mips16.od: Update test. diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp index 0a718cfb88..47911a68c1 100644 --- a/ld/testsuite/ld-i386/i386.exp +++ b/ld/testsuite/ld-i386/i386.exp @@ -309,6 +309,7 @@ run_dump_test "pr14215" run_dump_test "pr17057" run_dump_test "pr17935-1" run_dump_test "pr17935-2" +run_dump_test "pr18801" run_dump_test "pr18815" # Add $PLT_CFLAGS if PLT is expected. diff --git a/ld/testsuite/ld-i386/pr18801.d b/ld/testsuite/ld-i386/pr18801.d new file mode 100644 index 0000000000..4bb2efb9f7 --- /dev/null +++ b/ld/testsuite/ld-i386/pr18801.d @@ -0,0 +1,3 @@ +#as: --32 +#ld: -m elf_i386 -pie +#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC diff --git a/ld/testsuite/ld-i386/pr18801.s b/ld/testsuite/ld-i386/pr18801.s new file mode 100644 index 0000000000..ac3377dc62 --- /dev/null +++ b/ld/testsuite/ld-i386/pr18801.s @@ -0,0 +1,15 @@ + .text + .type selector, %function +foo: + movl $0, %eax + ret +selector: + mov $foo, %eax + ret + .type selector, %gnu_indirect_function + .globl _start +_start: + mov $selector, %eax + call *%eax + ret + .section .note.GNU-stack,"",@progbits diff --git a/ld/testsuite/ld-x86-64/pr18801.d b/ld/testsuite/ld-x86-64/pr18801.d new file mode 100644 index 0000000000..459db6bb29 --- /dev/null +++ b/ld/testsuite/ld-x86-64/pr18801.d @@ -0,0 +1,3 @@ +#as: --64 +#ld: -melf_x86_64 -pie +#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC diff --git a/ld/testsuite/ld-x86-64/pr18801.s b/ld/testsuite/ld-x86-64/pr18801.s new file mode 100644 index 0000000000..16d36dabe0 --- /dev/null +++ b/ld/testsuite/ld-x86-64/pr18801.s @@ -0,0 +1,15 @@ + .text + .type selector, %function +foo: + movl $0, %eax + ret +selector: + movabs $foo, %rax + ret + .type selector, %gnu_indirect_function + .globl _start +_start: + movabs $selector, %rax + call *%rax + ret + .section .note.GNU-stack,"",@progbits diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp index bd48cd3c6e..5409dff41e 100644 --- a/ld/testsuite/ld-x86-64/x86-64.exp +++ b/ld/testsuite/ld-x86-64/x86-64.exp @@ -325,6 +325,7 @@ run_dump_test "pr17935-1" run_dump_test "pr17935-2" run_dump_test "pr18160" run_dump_test "pr18176" +run_dump_test "pr18801" run_dump_test "pr18815" # Add $PLT_CFLAGS if PLT is expected. -- 2.34.1