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[committed, PATCH] PR ld/18801: PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: binutils at sourceware dot org
- Date: Thu, 13 Aug 2015 04:46:22 -0700
- Subject: [committed, PATCH] PR ld/18801: PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
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 e561764..9ba5902 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2015-08-13 H.J. Lu <hongjiu.lu@intel.com>
+
+ 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 <simon.dardis@imgtec.com>
* elfxx-mips.c (STUB_MOVE): Change to use 'or' only.
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 3063bed..1e4c3f4 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 2d3c55e..348b297 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 a38dc8b..5ae5cd4 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2015-08-13 H.J. Lu <hongjiu.lu@intel.com>
+
+ 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 <simon.dardis@imgtec.com>
* 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 0a718cf..47911a6 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 0000000..4bb2efb
--- /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 0000000..ac3377d
--- /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 0000000..459db6b
--- /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 0000000..16d36da
--- /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 bd48cd3..5409dff 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.
--
2.4.3