Hello, This is an updated patch for static pie support on i386, x86_64, and arm. I added dependency checks to ensure it only affects supported architectures. I also added a check to ensure an MMU is present on arm since there is no support for FDPIC yet.
Hello,
Looks great :)
Comments inline:
Le 15/07/2022 à 22:26, linted a écrit :
Sujet : [uclibc-ng-devel] [Patch v2] Static PIE support for i386, x86_64, and arm De : linted linted90@gmail.com Date : 15/07/2022, 22:26
Pour : devel@uclibc-ng.org
Hello, This is an updated patch for static pie support on i386, x86_64, and arm. I added dependency checks to ensure it only affects supported architectures. I also added a check to ensure an MMU is present on arm since there is no support for FDPIC yet.
0001-Added-static-pie-support-for-i368-x86_64-and-arm.patch
From 98313d17220486a75a0e552df045c6752a5ad25b Mon Sep 17 00:00:00 2001 From: lintedlinted@users.noreply.github.com Date: Fri, 15 Jul 2022 16:15:14 -0400 Subject: [PATCH] Added static pie support for i368, x86_64 and arm
Maybe add some more description of how this is done in the commit message?
Signed-off-by: lintedlinted@users.noreply.github.com
Makerules | 5 ++++ extra/Configs/Config.in | 7 ++++- libc/misc/internals/Makefile.in | 1 + libc/misc/internals/reloc_static_pie.c | 39 ++++++++++++++++++++++++++ libc/sysdeps/linux/arm/crt1.S | 15 ++++++++++ libc/sysdeps/linux/i386/crt1.S | 20 +++++++++++++ libc/sysdeps/linux/x86_64/crt1.S | 16 ++++++++++- 7 files changed, 101 insertions(+), 2 deletions(-) create mode 100644 libc/misc/internals/reloc_static_pie.c
diff --git a/Makerules b/Makerules index fd40e6c7b..845d81897 100644 --- a/Makerules +++ b/Makerules @@ -405,8 +405,13 @@ else CRTS=$(top_builddir)lib/$(CRT).o endif
+ifeq ($(STATIC_PIE),y) +CRTS+=$(top_builddir)lib/r$(CRT).o +endif
- ASFLAGS-$(CRT).o := -DL_$(CRT) ASFLAGS-S$(CRT).o := $(PIEFLAG) -DL_S$(CRT)
+ASFLAGS-r$(CRT).o := $(PIEFLAG) -DL_r$(CRT) $(CRTS): $(top_srcdir)libc/sysdeps/linux/$(TARGET_ARCH)/$(CRT).S $(compile.S) $(Q)$(STRIPTOOL) -x -R .note -R .comment $@ diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in index a58ceb265..ac5c494c3 100644 --- a/extra/Configs/Config.in +++ b/extra/Configs/Config.in @@ -301,6 +301,11 @@ config DOPIC If you wish to build all of uClibc as PIC objects, then answer Y here. If you are unsure, then you should answer N.
+config STATIC_PIE
- bool "Add support for Static Position Independent Executables (PIE)"
- default n
- depends on DOPIC && !UCLIBC_FORMAT_FDPIC_ELF && (TARGET_arm || TARGET_i386 || TARGET_x86_64)
- config ARCH_HAS_NO_SHARED bool
@@ -1757,7 +1762,7 @@ config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION fflush function or to a file positioning function (fseek, fsetpos, or rewind), and input shall not be directly followed by output without an intervening call to a file positioning function, unless the input
operation encounters end�of�file.
operation encounters end�of�file.
This seems like a spurious modification due to the text editor?
Most people will answer Y.diff --git a/libc/misc/internals/Makefile.in b/libc/misc/internals/Makefile.in index a8e4e36f9..4a6e73d2d 100644 --- a/libc/misc/internals/Makefile.in +++ b/libc/misc/internals/Makefile.in @@ -34,6 +34,7 @@ libc-static-$(UCLIBC_FORMAT_FLAT_SEP_DATA) += \ libc-static-$(UCLIBC_FORMAT_SHARED_FLAT) += \ $(MISC_INTERNALS_OUT)/shared_flat_initfini.o \ $(MISC_INTERNALS_OUT)/shared_flat_add_library.o +libc-static-$(STATIC_PIE) += $(MISC_INTERNALS_OUT)/reloc_static_pie.o libc-shared-$(UCLIBC_FORMAT_SHARED_FLAT) += \ $(MISC_INTERNALS_OUT)/shared_flat_initfini.os \ $(MISC_INTERNALS_OUT)/shared_flat_add_library.os diff --git a/libc/misc/internals/reloc_static_pie.c b/libc/misc/internals/reloc_static_pie.c new file mode 100644 index 000000000..0736bc8a1 --- /dev/null +++ b/libc/misc/internals/reloc_static_pie.c @@ -0,0 +1,39 @@ +/* Support for relocating static PIE.
- Copyright (C) 2017-2022 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
+https://www.gnu.org/licenses/. */
+#include <link.h> +#include <elf.h> +#include <dl-elf.h>
+void +reloc_static_pie (ElfW(Addr) load_addr) +{
- /* Read our own dynamic section and fill in the info array. */
- ElfW(Dyn) * dyn_addr = ((void *) load_addr + elf_machine_dynamic ());
- unsigned long dynamic_info[36] = {0};
Could you use some generic define for the size of dynamic_info instead of the hard coded 36?
Like DYNAMIC_SIZE for instance? (I haven't checked if it's the correct value for you)
- /* Use the underlying function to avoid TLS access before initialization */
- __dl_parse_dynamic_info(dyn_addr, dynamic_info, NULL, load_addr);
- ElfW(Word) relative_count = dynamic_info[DT_RELCONT_IDX];
- ElfW(Addr) rel_addr = dynamic_info[DT_RELOC_TABLE_ADDR];
Maybe declare relative_count and rel_addr at the beginning of the function?
- elf_machine_relative(load_addr, rel_addr, relative_count);
- return;
I would remove the return.
+} diff --git a/libc/sysdeps/linux/arm/crt1.S b/libc/sysdeps/linux/arm/crt1.S index a1d7f0f23..adaf4b983 100644 --- a/libc/sysdeps/linux/arm/crt1.S +++ b/libc/sysdeps/linux/arm/crt1.S @@ -246,6 +246,18 @@ _start: mov lr, #0
#ifdef __ARCH_USE_MMU__ +#ifdef L_rcrt1
- /* We don't need to save a1 since no dynamic linker should have run */
- ldr a1, .L_GOT /* Get value at .L_GOT + 0 (offset to GOT)*/
- adr a2, .L_GOT /* Get address of .L_GOT */
- ldr a3, .L_GOT+16 /* get value of _start(GOT) stored in .L_GOT */
- adr a4, _start /* get address of _start after relocation (changes to pc - ~30 or so) */
- add a1, a1, a2 /* calculate where the GOT is */
- ldr a2, [a1, a3] /* GOT + _start(GOT) = offset of _start from begin of file */
- sub a1, a4, a2 /* current addr of _start - offset from beginning of file = load addr */
- bl reloc_static_pie
- mov a1, #0 /* Clean up a1 so that a random address won't get called at the end of program */
+#endif /* Pop argc off the stack and save a pointer to argv */ ldr a2, [sp], #4 mov a3, sp @@ -309,6 +321,9 @@ _start: .word _fini(GOT) .word _init(GOT) .word main(GOT) +#ifdef L_rcrt1
- .word _start(GOT)
+#endif #endif #endif
diff --git a/libc/sysdeps/linux/i386/crt1.S b/libc/sysdeps/linux/i386/crt1.S index 35a6552e8..4e4cef3ce 100644 --- a/libc/sysdeps/linux/i386/crt1.S +++ b/libc/sysdeps/linux/i386/crt1.S @@ -67,6 +67,9 @@ #endif .type main,%function .type __uClibc_main,%function +#ifdef L_rcrt1 +.type reloc_static_pie,%function +#endif _start: /* Clear the frame pointer. The ABI suggests this be done, to mark the outermost frame obviously. */ @@ -100,6 +103,23 @@ _start: pop %ebx addl $_GLOBAL_OFFSET_TABLE_+[.-.L0],%ebx
+#ifdef L_rcrt1
- /* We cannot rely on _DYNAMIC being usable here due to RELRO.
Instead we calculate the load address based off a symbolthat we know will exist, _start. */
nitpick: the comments of the assembly code for arm crt1.S are well aligned whereas those for i386/x86_64 are not well aligned.
- pushl %ecx /* Save ecx so it won't get clobbered */
- pushl %ebx /* Save ebx so it won't get clobbered */
- xorl %ecx, %ecx /* Clear ecx */
- addl _start@GOT(%ebx), %ecx /* Get the offset of _start */
- movl _start@GOT(%ebx), %eax /* Get the run time address of _start */
- subl %ecx, %eax /* Subtract to find the load address */
- pushl %eax /* Pass the load address */
- call reloc_static_pie@PLT
- popl %eax /* Clean up from function call */
- popl %ebx /* Restore the GOT address */
- popl %ecx /* restore ecx */
+#endif
- /* Push address of our own entry points to .fini and .init. */ pushl _fini@GOT(%ebx) pushl _init@GOT(%ebx)
diff --git a/libc/sysdeps/linux/x86_64/crt1.S b/libc/sysdeps/linux/x86_64/crt1.S index 87777dd5d..04536d07f 100644 --- a/libc/sysdeps/linux/x86_64/crt1.S +++ b/libc/sysdeps/linux/x86_64/crt1.S @@ -80,6 +80,20 @@ _start: the outermost frame obviously. */ xorl %ebp, %ebp
+#ifdef L_rcrt1
- pushq %rdi /* save rdi (but should be 0...) */
- pushq %rdx /* store rdx (rtld_fini) */
- xorq %rcx, %rcx /* ensure rcx is 0 */
- addq _start@GOTPCREL(%rip), %rcx /* get offset of _start from beginning of file */
- movq _start@GOTPCREL(%rip), %rax /* get run time address of _start */
- subq %rcx, %rax /* calculate run time load offset */
- movq %rax, %rdi /* load offset -> param 1 */
- call reloc_static_pie /* relocate dynamic addrs */
- xorq %rax, %rax /* cleanup */
- popq %rdx
- popq %rdi
+#endif
- /* Extract the arguments as encoded on the stack and set up the arguments for __libc_start_main (int (*main) (int, char **, char **), int argc, char *argv,
@@ -107,7 +121,7 @@ _start: which grow downwards). */ pushq %rsp
-#if defined(L_Scrt1) +#if defined(L_Scrt1) || defined(L_rcrt1) /* Give address for main() */ movq main@GOTPCREL(%rip), %rdi
-- 2.34.1
devel mailing list --devel@uclibc-ng.org To unsubscribe send an email todevel-leave@uclibc-ng.org Pièces jointes :
0001-Added-static-pie-support-for-i368-x86_64-and-arm.patch 8,2 Ko
I did a little bit of research, and you are completely right, I should have been using DYNAMIC_SIZE rather than the static 36. I'm not entirely sure what to do about the format of the comments. It seems to be a tabs vs spaces issue. Both files swap between tabs and spaces in different places throughout the file. I think that if I swap over to spaces it might make it look a little cleaner though. I'll resubmit with the other changes you suggested.
On Sat, Jul 16, 2022 at 5:27 AM Yann Sionneau yann@sionneau.net wrote:
Hello,
Looks great :)
Comments inline:
Le 15/07/2022 à 22:26, linted a écrit :
Sujet : [uclibc-ng-devel] [Patch v2] Static PIE support for i386, x86_64, and arm De : linted linted90@gmail.com Date : 15/07/2022, 22:26
Pour : devel@uclibc-ng.org
Hello, This is an updated patch for static pie support on i386, x86_64, and arm. I added dependency checks to ensure it only affects supported architectures. I also added a check to ensure an MMU is present on arm since there is no support for FDPIC yet.
0001-Added-static-pie-support-for-i368-x86_64-and-arm.patch
From 98313d17220486a75a0e552df045c6752a5ad25b Mon Sep 17 00:00:00 2001 From: lintedlinted@users.noreply.github.com Date: Fri, 15 Jul 2022 16:15:14 -0400 Subject: [PATCH] Added static pie support for i368, x86_64 and arm
Maybe add some more description of how this is done in the commit message?
Signed-off-by: lintedlinted@users.noreply.github.com
Makerules | 5 ++++ extra/Configs/Config.in | 7 ++++- libc/misc/internals/Makefile.in | 1 + libc/misc/internals/reloc_static_pie.c | 39 ++++++++++++++++++++++++++ libc/sysdeps/linux/arm/crt1.S | 15 ++++++++++ libc/sysdeps/linux/i386/crt1.S | 20 +++++++++++++ libc/sysdeps/linux/x86_64/crt1.S | 16 ++++++++++- 7 files changed, 101 insertions(+), 2 deletions(-) create mode 100644 libc/misc/internals/reloc_static_pie.c
diff --git a/Makerules b/Makerules index fd40e6c7b..845d81897 100644 --- a/Makerules +++ b/Makerules @@ -405,8 +405,13 @@ else CRTS=$(top_builddir)lib/$(CRT).o endif
+ifeq ($(STATIC_PIE),y) +CRTS+=$(top_builddir)lib/r$(CRT).o +endif
- ASFLAGS-$(CRT).o := -DL_$(CRT) ASFLAGS-S$(CRT).o := $(PIEFLAG) -DL_S$(CRT)
+ASFLAGS-r$(CRT).o := $(PIEFLAG) -DL_r$(CRT) $(CRTS): $(top_srcdir)libc/sysdeps/linux/$(TARGET_ARCH)/$(CRT).S $(compile.S) $(Q)$(STRIPTOOL) -x -R .note -R .comment $@ diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in index a58ceb265..ac5c494c3 100644 --- a/extra/Configs/Config.in +++ b/extra/Configs/Config.in @@ -301,6 +301,11 @@ config DOPIC If you wish to build all of uClibc as PIC objects, then answer Y
here.
If you are unsure, then you should answer N.+config STATIC_PIE
bool "Add support for Static Position Independent Executables(PIE)"
default ndepends on DOPIC && !UCLIBC_FORMAT_FDPIC_ELF && (TARGET_arm ||TARGET_i386 || TARGET_x86_64)
- config ARCH_HAS_NO_SHARED bool
@@ -1757,7 +1762,7 @@ config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION fflush function or to a file positioning function (fseek,
fsetpos,
or rewind), and input shall not be directly followed by outputwithout
an intervening call to a file positioning function, unless theinput
operation encounters end�of�file.
operation encounters end�of�file.This seems like a spurious modification due to the text editor?
Most people will answer Y.diff --git a/libc/misc/internals/Makefile.in
b/libc/misc/internals/Makefile.in
index a8e4e36f9..4a6e73d2d 100644 --- a/libc/misc/internals/Makefile.in +++ b/libc/misc/internals/Makefile.in @@ -34,6 +34,7 @@ libc-static-$(UCLIBC_FORMAT_FLAT_SEP_DATA) += \ libc-static-$(UCLIBC_FORMAT_SHARED_FLAT) += \ $(MISC_INTERNALS_OUT)/shared_flat_initfini.o \ $(MISC_INTERNALS_OUT)/shared_flat_add_library.o +libc-static-$(STATIC_PIE) += $(MISC_INTERNALS_OUT)/reloc_static_pie.o libc-shared-$(UCLIBC_FORMAT_SHARED_FLAT) += \ $(MISC_INTERNALS_OUT)/shared_flat_initfini.os \ $(MISC_INTERNALS_OUT)/shared_flat_add_library.os diff --git a/libc/misc/internals/reloc_static_pie.c
b/libc/misc/internals/reloc_static_pie.c
new file mode 100644 index 000000000..0736bc8a1 --- /dev/null +++ b/libc/misc/internals/reloc_static_pie.c @@ -0,0 +1,39 @@ +/* Support for relocating static PIE.
- Copyright (C) 2017-2022 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
+https://www.gnu.org/licenses/. */
+#include <link.h> +#include <elf.h> +#include <dl-elf.h>
+void +reloc_static_pie (ElfW(Addr) load_addr) +{
- /* Read our own dynamic section and fill in the info array. */
- ElfW(Dyn) * dyn_addr = ((void *) load_addr + elf_machine_dynamic
());
- unsigned long dynamic_info[36] = {0};
Could you use some generic define for the size of dynamic_info instead of the hard coded 36?
Like DYNAMIC_SIZE for instance? (I haven't checked if it's the correct value for you)
- /* Use the underlying function to avoid TLS access before
initialization */
- __dl_parse_dynamic_info(dyn_addr, dynamic_info, NULL, load_addr);
- ElfW(Word) relative_count = dynamic_info[DT_RELCONT_IDX];
- ElfW(Addr) rel_addr = dynamic_info[DT_RELOC_TABLE_ADDR];
Maybe declare relative_count and rel_addr at the beginning of the function?
- elf_machine_relative(load_addr, rel_addr, relative_count);
- return;
I would remove the return.
+} diff --git a/libc/sysdeps/linux/arm/crt1.S
b/libc/sysdeps/linux/arm/crt1.S
index a1d7f0f23..adaf4b983 100644 --- a/libc/sysdeps/linux/arm/crt1.S +++ b/libc/sysdeps/linux/arm/crt1.S @@ -246,6 +246,18 @@ _start: mov lr, #0
#ifdef __ARCH_USE_MMU__ +#ifdef L_rcrt1
/* We don't need to save a1 since no dynamic linker should haverun */
ldr a1, .L_GOT /* Get value at .L_GOT + 0 (offset toGOT)*/
adr a2, .L_GOT /* Get address of .L_GOT */ldr a3, .L_GOT+16 /* get value of _start(GOT) stored in.L_GOT */
adr a4, _start /* get address of _start after relocation(changes to pc - ~30 or so) */
add a1, a1, a2 /* calculate where the GOT is */ldr a2, [a1, a3] /* GOT + _start(GOT) = offset of _startfrom begin of file */
sub a1, a4, a2 /* current addr of _start - offset frombeginning of file = load addr */
bl reloc_static_piemov a1, #0 /* Clean up a1 so that a randomaddress won't get called at the end of program */
+#endif /* Pop argc off the stack and save a pointer to argv */ ldr a2, [sp], #4 mov a3, sp @@ -309,6 +321,9 @@ _start: .word _fini(GOT) .word _init(GOT) .word main(GOT) +#ifdef L_rcrt1
.word _start(GOT)+#endif #endif #endif
diff --git a/libc/sysdeps/linux/i386/crt1.S
b/libc/sysdeps/linux/i386/crt1.S
index 35a6552e8..4e4cef3ce 100644 --- a/libc/sysdeps/linux/i386/crt1.S +++ b/libc/sysdeps/linux/i386/crt1.S @@ -67,6 +67,9 @@ #endif .type main,%function .type __uClibc_main,%function +#ifdef L_rcrt1 +.type reloc_static_pie,%function +#endif _start: /* Clear the frame pointer. The ABI suggests this be done, to mark the outermost frame obviously. */ @@ -100,6 +103,23 @@ _start: pop %ebx addl $_GLOBAL_OFFSET_TABLE_+[.-.L0],%ebx
+#ifdef L_rcrt1
/* We cannot rely on _DYNAMIC being usable here due to RELRO.Instead we calculate the load address based off a symbolthat we know will exist, _start. */nitpick: the comments of the assembly code for arm crt1.S are well aligned whereas those for i386/x86_64 are not well aligned.
pushl %ecx /* Saveecx so it won't get clobbered */
pushl %ebx /* Saveebx so it won't get clobbered */
xorl %ecx, %ecx /* Clear ecx */addl _start@GOT(%ebx), %ecx /* Get the offset of _start */movl _start@GOT(%ebx), %eax /* Get the run time address of_start */
subl %ecx, %eax /* Subtract tofind the load address */
pushl %eax /* Passthe load address */
call reloc_static_pie@PLTpopl %eax /* Cleanup from function call */
popl %ebx /* Restorethe GOT address */
popl %ecx /* restoreecx */
+#endif
/* Push address of our own entry points to .fini and .init. */ pushl _fini@GOT(%ebx) pushl _init@GOT(%ebx)diff --git a/libc/sysdeps/linux/x86_64/crt1.S
b/libc/sysdeps/linux/x86_64/crt1.S
index 87777dd5d..04536d07f 100644 --- a/libc/sysdeps/linux/x86_64/crt1.S +++ b/libc/sysdeps/linux/x86_64/crt1.S @@ -80,6 +80,20 @@ _start: the outermost frame obviously. */ xorl %ebp, %ebp
+#ifdef L_rcrt1
pushq %rdi /*save rdi (but should be 0...) */
pushq %rdx /*store rdx (rtld_fini) */
xorq %rcx, %rcx /* ensurercx is 0 */
addq _start@GOTPCREL(%rip), %rcx /* get offset of _startfrom beginning of file */
movq _start@GOTPCREL(%rip), %rax /* get run time addressof _start */
subq %rcx, %rax /*calculate run time load offset */
movq %rax, %rdi /* loadoffset -> param 1 */
call reloc_static_pie /* relocatedynamic addrs */
xorq %rax, %rax /* cleanup*/
popq %rdxpopq %rdi+#endif
/* Extract the arguments as encoded on the stack and set up the arguments for __libc_start_main (int (*main) (int, char **,char **),
int argc, char *argv,@@ -107,7 +121,7 @@ _start: which grow downwards). */ pushq %rsp
-#if defined(L_Scrt1) +#if defined(L_Scrt1) || defined(L_rcrt1) /* Give address for main() */ movq main@GOTPCREL(%rip), %rdi
-- 2.34.1
devel mailing list --devel@uclibc-ng.org To unsubscribe send an email todevel-leave@uclibc-ng.org Pièces jointes :
0001-Added-static-pie-support-for-i368-x86_64-and-arm.patch 8,2 Ko
devel mailing list -- devel@uclibc-ng.org To unsubscribe send an email to devel-leave@uclibc-ng.org
-
linted -
Yann Sionneau