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llvm-project/lld/test/ELF/relro-non-contiguous.s

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[ELF] Move `// REQUIRES:` line to the top llvm-svn: 335676
2018-06-27 06:20:04 +08:00
// REQUIRES: x86
[ELF] Give error message when relro sections are not contiguous. If a linker script is used that names linker generated synthetic sections it is possible that the OutputSections for which isRelroSection() is true are not contiguous. When the relro sections are not contiguous we cannot describe them with a single PT_GNU_RELRO PHDR. Unfortunately at least one contemporary dynamic loader only supports one PT_GNU_RELRO PHDR so we cannot output more than one of these PHDRs. As not including relro sections in the PHDR will lead to security sensitive sections being writeable we choose to give an error message instead. Differential Revision: https://reviews.llvm.org/D40359 [ELF] Skip over empty sections when checking for contiguous relro llvm-svn: 318920
2017-11-23 22:53:10 +08:00
// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/shared.s -o %t.o
// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/copy-in-shared.s -o %t2.o
// RUN: ld.lld -shared %t.o %t2.o -o %t.so
[ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss) New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss) The placement of | indicates page alignment caused by PT_GNU_RELRO. The new layout has simpler rules and saves space for many cases. Old size: roundup(.data) + roundup(.data.rel.ro) New size: roundup(.data.rel.ro + .bss.rel.ro) + .data Other advantages: * At runtime the 3 memory mappings decrease to 2. * start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This simplifies binary manipulation tools. GNU strip before 2.31 discards PT_GNU_RELRO if its address is not equal to the start of its associated PT_LOAD. This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f But with this change, we will be compatible with GNU strip before 2.31 * Before, .got.plt (non-relro by default) was placed before .got (relro by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_ (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END) (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we can improve on this regard if we'd like to. Reviewers: ruiu, espindola, pcc Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert Differential Revision: https://reviews.llvm.org/D56828 llvm-svn: 356117
2019-03-14 11:47:45 +08:00
// Separate RelRo sections .dynamic .bss.rel.ro with non RelRo .got.plt.
// This causes the RelRo sections to be non-contiguous.
[ELF] Give error message when relro sections are not contiguous. If a linker script is used that names linker generated synthetic sections it is possible that the OutputSections for which isRelroSection() is true are not contiguous. When the relro sections are not contiguous we cannot describe them with a single PT_GNU_RELRO PHDR. Unfortunately at least one contemporary dynamic loader only supports one PT_GNU_RELRO PHDR so we cannot output more than one of these PHDRs. As not including relro sections in the PHDR will lead to security sensitive sections being writeable we choose to give an error message instead. Differential Revision: https://reviews.llvm.org/D40359 [ELF] Skip over empty sections when checking for contiguous relro llvm-svn: 318920
2017-11-23 22:53:10 +08:00
// RUN: echo "SECTIONS { \
// RUN: .dynamic : { *(.dynamic) } \
// RUN: .got.plt : { *(.got.plt) } \
[ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss) New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss) The placement of | indicates page alignment caused by PT_GNU_RELRO. The new layout has simpler rules and saves space for many cases. Old size: roundup(.data) + roundup(.data.rel.ro) New size: roundup(.data.rel.ro + .bss.rel.ro) + .data Other advantages: * At runtime the 3 memory mappings decrease to 2. * start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This simplifies binary manipulation tools. GNU strip before 2.31 discards PT_GNU_RELRO if its address is not equal to the start of its associated PT_LOAD. This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f But with this change, we will be compatible with GNU strip before 2.31 * Before, .got.plt (non-relro by default) was placed before .got (relro by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_ (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END) (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we can improve on this regard if we'd like to. Reviewers: ruiu, espindola, pcc Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert Differential Revision: https://reviews.llvm.org/D56828 llvm-svn: 356117
2019-03-14 11:47:45 +08:00
// RUN: .bss.rel.ro : { *(.bss.rel.o) } \
[ELF] Give error message when relro sections are not contiguous. If a linker script is used that names linker generated synthetic sections it is possible that the OutputSections for which isRelroSection() is true are not contiguous. When the relro sections are not contiguous we cannot describe them with a single PT_GNU_RELRO PHDR. Unfortunately at least one contemporary dynamic loader only supports one PT_GNU_RELRO PHDR so we cannot output more than one of these PHDRs. As not including relro sections in the PHDR will lead to security sensitive sections being writeable we choose to give an error message instead. Differential Revision: https://reviews.llvm.org/D40359 [ELF] Skip over empty sections when checking for contiguous relro llvm-svn: 318920
2017-11-23 22:53:10 +08:00
// RUN: } " > %t.script
// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t3.o
// Expect error for non-contiguous relro
// RUN: not ld.lld %t3.o %t.so -z relro -o %t --script=%t.script 2>&1 | FileCheck %s
// No error when we do not request relro.
// RUN: ld.lld %t3.o %t.so -z norelro -o %t --script=%t.script
// CHECK: error: section: .bss.rel.ro is not contiguous with other relro sections
.section .text, "ax", @progbits
.global _start
.global bar
.global foo
_start:
.quad bar
.quad foo