| Message ID | 20170116090031.4843668B50@localhost.localdomain (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
On Mon, 16 Jan 2017, Christophe Leroy wrote: > Christian, can you test it ? OK, so with that applied to v4.10-rc4, compilation still fails with GCC 4.9.2 and CC_STACKPROTECTOR_STRONG=y, see below. But it compiles just fine with CC_STACKPROTECTOR_REGULAR=y and boots to! Cross-compiling the same with GCC 5.2.0 works, even for CC_STACKPROTECTOR_STRONG=y and the system boots just fine. So, with that limitation, feel free to add: Tested-by: Christian Kujau <lists@nerdbynature.de> Thanks for the fix! Christian. ---- $ gcc --version | head -1 gcc-4.9.real (Debian 4.9.2-10) 4.9.2 $ grep CC_STACKPROTECTOR_STRONG $DIR/.config CONFIG_CC_STACKPROTECTOR_STRONG=y $ make O=$DIR V=1 bindeb-pkg [...] + ld -EB -m elf32ppc -Bstatic --build-id -X -o .tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds arch/powerpc/kernel/head_32.o arch/powerpc/kernel/fpu.o arch/powerpc/kernel/vector.o arch/powerpc/kernel/prom_init.o init/built-in.o --start-group usr/built-in.o arch/powerpc/kernel/built-in.o arch/powerpc/mm/built-in.o arch/powerpc/lib/built-in.o arch/powerpc/sysdev/built-in.o arch/powerpc/platforms/built-in.o arch/powerpc/math-emu/built-in.o arch/powerpc/crypto/built-in.o arch/powerpc/net/built-in.o kernel/built-in.o certs/built-in.o mm/built-in.o fs/built-in.o ipc/built-in.o security/built-in.o crypto/built-in.o block/built-in.o lib/lib.a lib/built-in.o drivers/built-in.o sound/built-in.o firmware/built-in.o net/built-in.o virt/built-in.o --end-group arch/powerpc/platforms/built-in.o: In function `bootx_printf': /usr/local/src/linux-git/arch/powerpc/platforms/powermac/bootx_init.c:88: undefined reference to `__stack_chk_fail_local' arch/powerpc/platforms/built-in.o: In function `bootx_add_display_props': /usr/local/src/linux-git/arch/powerpc/platforms/powermac/bootx_init.c:211: undefined reference to `__stack_chk_fail_local' arch/powerpc/platforms/built-in.o: In function `bootx_scan_dt_build_struct': /usr/local/src/linux-git/arch/powerpc/platforms/powermac/bootx_init.c:350: undefined reference to `__stack_chk_fail_local' arch/powerpc/platforms/built-in.o: In function `bootx_init': /usr/local/src/linux-git/arch/powerpc/platforms/powermac/bootx_init.c:596: undefined reference to `__stack_chk_fail_local' /usr/bin/ld.bfd.real: .tmp_vmlinux1: hidden symbol `__stack_chk_fail_local' isn't defined /usr/bin/ld.bfd.real: final link failed: Bad value
On Mon, 16 Jan 2017, Christophe Leroy wrote: > Since 2005, powerpc GCC doesn't manage anymore __stack_chk_guard as > a global variable but as some value located at -0x7008(r2) Is this still an "RFC" or is there a chance that this will land in 4.10? Thanks, Christian. > In the Linux kernel, r2 is used as a pointer to current task struct. > > This patch changes the meaning of r2 when stack protector > is activated: > - current is taken from thread_info and not kept in r2 anymore > - r2 is set to current + offset of stack canary + 0x7008 so > that -0x7008(r2) directly points to current->stack_canary > > current could have been more efficiently calculated from r2 > but some circular inclusion prevent inserting struct task_struct > into arch/powerpc/include/asm/current.h so it is not possible > to get offset of stack_canary within current task_struct from there. > > fixes: 6533b7c16ee57 ("powerpc: Initial stack protector > (-fstack-protector) support") > Reported-by: Christian Kujau <lists@nerdbynature.de> > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > --- > Christian, can you test it ? > > arch/powerpc/include/asm/current.h | 12 +++++++++++- > arch/powerpc/include/asm/stackprotector.h | 13 +++++++++---- > arch/powerpc/kernel/entry_32.S | 19 +++++++++++++++---- > arch/powerpc/kernel/head_32.S | 7 +++++++ > arch/powerpc/kernel/head_40x.S | 4 ++++ > arch/powerpc/kernel/head_44x.S | 4 ++++ > arch/powerpc/kernel/head_8xx.S | 4 ++++ > arch/powerpc/kernel/head_fsl_booke.S | 7 +++++++ > arch/powerpc/kernel/process.c | 6 ------ > 9 files changed, 61 insertions(+), 15 deletions(-) > > diff --git a/arch/powerpc/include/asm/current.h b/arch/powerpc/include/asm/current.h > index e2c7f06..2f67f02 100644 > --- a/arch/powerpc/include/asm/current.h > +++ b/arch/powerpc/include/asm/current.h > @@ -27,8 +27,16 @@ static inline struct task_struct *get_current(void) > } > #define current get_current() > > -#else > +#else /* __powerpc64__ */ > +#if defined(CONFIG_CC_STACKPROTECTOR) > +#include <linux/thread_info.h> > > +static inline struct task_struct *get_current(void) > +{ > + return current_thread_info()->task; > +} > +#define current get_current() > +#else > /* > * We keep `current' in r2 for speed. > */ > @@ -36,5 +44,7 @@ register struct task_struct *current asm ("r2"); > > #endif > > +#endif /* __powerpc64__ */ > + > #endif /* __KERNEL__ */ > #endif /* _ASM_POWERPC_CURRENT_H */ > diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h > index 6720190..bf30509 100644 > --- a/arch/powerpc/include/asm/stackprotector.h > +++ b/arch/powerpc/include/asm/stackprotector.h > @@ -12,12 +12,18 @@ > #ifndef _ASM_STACKPROTECTOR_H > #define _ASM_STACKPROTECTOR_H > > +#ifdef CONFIG_PPC64 > +#define SSP_OFFSET 0x7010 > +#else > +#define SSP_OFFSET 0x7008 > +#endif > + > +#ifndef __ASSEMBLY__ > + > #include <linux/random.h> > #include <linux/version.h> > #include <asm/reg.h> > > -extern unsigned long __stack_chk_guard; > - > /* > * Initialize the stackprotector canary value. > * > @@ -34,7 +40,6 @@ static __always_inline void boot_init_stack_canary(void) > canary ^= LINUX_VERSION_CODE; > > current->stack_canary = canary; > - __stack_chk_guard = current->stack_canary; > } > - > +#endif /* __ASSEMBLY__ */ > #endif /* _ASM_STACKPROTECTOR_H */ > diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S > index 5742dbd..b3a363c 100644 > --- a/arch/powerpc/kernel/entry_32.S > +++ b/arch/powerpc/kernel/entry_32.S > @@ -34,6 +34,7 @@ > #include <asm/ftrace.h> > #include <asm/ptrace.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > > /* > * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. > @@ -149,6 +150,9 @@ transfer_to_handler: > mfspr r12,SPRN_SPRG_THREAD > addi r2,r12,-THREAD > tovirt(r2,r2) /* set r2 to current */ > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > beq 2f /* if from user, fix up THREAD.regs */ > addi r11,r1,STACK_FRAME_OVERHEAD > stw r11,PT_REGS(r12) > @@ -385,6 +389,9 @@ syscall_exit_cont: > lwz r3,GPR3(r1) > 1: > #endif /* CONFIG_TRACE_IRQFLAGS */ > +#if defined(CONFIG_CC_STACKPROTECTOR) > + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) > /* If the process has its own DBCR0 value, load it up. The internal > debug mode bit tells us that dbcr0 should be loaded. */ > @@ -617,6 +624,9 @@ _GLOBAL(_switch) > stwu r1,-INT_FRAME_SIZE(r1) > mflr r0 > stw r0,INT_FRAME_SIZE+4(r1) > +#if defined(CONFIG_CC_STACKPROTECTOR) > + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > /* r3-r12 are caller saved -- Cort */ > SAVE_NVGPRS(r1) > stw r0,_NIP(r1) /* Return to switch caller */ > @@ -674,10 +684,8 @@ BEGIN_FTR_SECTION > mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */ > END_FTR_SECTION_IFSET(CPU_FTR_SPE) > #endif /* CONFIG_SPE */ > -#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) > - lwz r0,TSK_STACK_CANARY(r2) > - lis r4,__stack_chk_guard@ha > - stw r0,__stack_chk_guard@l(r4) > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > #endif > lwz r0,_CCR(r1) > mtcrf 0xFF,r0 > @@ -779,6 +787,9 @@ user_exc_return: /* r10 contains MSR_KERNEL here */ > bne do_work > > restore_user: > +#if defined(CONFIG_CC_STACKPROTECTOR) > + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) > /* Check whether this process has its own DBCR0 value. The internal > debug mode bit tells us that dbcr0 should be loaded. */ > diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S > index 9d96354..bae9b83 100644 > --- a/arch/powerpc/kernel/head_32.S > +++ b/arch/powerpc/kernel/head_32.S > @@ -35,6 +35,7 @@ > #include <asm/bug.h> > #include <asm/kvm_book3s_asm.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > > /* 601 only have IBAT; cr0.eq is set on 601 when using this macro */ > #define LOAD_BAT(n, reg, RA, RB) \ > @@ -864,6 +865,9 @@ __secondary_start: > tophys(r4,r2) > addi r4,r4,THREAD /* phys address of our thread_struct */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > li r3,0 > mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */ > > @@ -950,6 +954,9 @@ start_here: > tophys(r4,r2) > addi r4,r4,THREAD /* init task's THREAD */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > li r3,0 > mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */ > > diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S > index 41374a4..20b1c31 100644 > --- a/arch/powerpc/kernel/head_40x.S > +++ b/arch/powerpc/kernel/head_40x.S > @@ -42,6 +42,7 @@ > #include <asm/asm-offsets.h> > #include <asm/ptrace.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > > /* As with the other PowerPC ports, it is expected that when code > * execution begins here, the following registers contain valid, yet > @@ -835,6 +836,9 @@ start_here: > tophys(r4,r2) > addi r4,r4,THREAD /* init task's THREAD */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > > /* stack */ > lis r1,init_thread_union@ha > diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S > index 37e4a7c..753e2bf 100644 > --- a/arch/powerpc/kernel/head_44x.S > +++ b/arch/powerpc/kernel/head_44x.S > @@ -40,6 +40,7 @@ > #include <asm/ptrace.h> > #include <asm/synch.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > #include "head_booke.h" > > > @@ -107,6 +108,9 @@ _ENTRY(_start); > /* ptr to current thread */ > addi r4,r2,THREAD /* init task's THREAD */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > > /* stack */ > lis r1,init_thread_union@h > diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S > index 1a9c99d..49f9ce1 100644 > --- a/arch/powerpc/kernel/head_8xx.S > +++ b/arch/powerpc/kernel/head_8xx.S > @@ -32,6 +32,7 @@ > #include <asm/ptrace.h> > #include <asm/fixmap.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > > /* Macro to make the code more readable. */ > #ifdef CONFIG_8xx_CPU6 > @@ -820,6 +821,9 @@ start_here: > tophys(r4,r2) > addi r4,r4,THREAD /* init task's THREAD */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > > /* stack */ > lis r1,init_thread_union@ha > diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S > index bf4c602..9634ac7 100644 > --- a/arch/powerpc/kernel/head_fsl_booke.S > +++ b/arch/powerpc/kernel/head_fsl_booke.S > @@ -43,6 +43,7 @@ > #include <asm/cache.h> > #include <asm/ptrace.h> > #include <asm/export.h> > +#include <asm/stackprotector.h> > #include "head_booke.h" > > /* As with the other PowerPC ports, it is expected that when code > @@ -235,6 +236,9 @@ set_ivor: > /* ptr to current thread */ > addi r4,r2,THREAD /* init task's THREAD */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > > /* stack */ > lis r1,init_thread_union@h > @@ -1086,6 +1090,9 @@ __secondary_start: > /* ptr to current thread */ > addi r4,r2,THREAD /* address of our thread_struct */ > mtspr SPRN_SPRG_THREAD,r4 > +#if defined(CONFIG_CC_STACKPROTECTOR) > + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET > +#endif > > /* Setup the defaults for TLB entries */ > li r4,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index 04885ce..5dd056d 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -64,12 +64,6 @@ > #include <linux/kprobes.h> > #include <linux/kdebug.h> > > -#ifdef CONFIG_CC_STACKPROTECTOR > -#include <linux/stackprotector.h> > -unsigned long __stack_chk_guard __read_mostly; > -EXPORT_SYMBOL(__stack_chk_guard); > -#endif > - > /* Transactional Memory debug */ > #ifdef TM_DEBUG_SW > #define TM_DEBUG(x...) printk(KERN_INFO x) > -- > 2.10.1 > >
On Mon, Jan 30, 2017 at 04:12:53PM -0800, Christian Kujau wrote: > On Mon, 16 Jan 2017, Christophe Leroy wrote: > > Since 2005, powerpc GCC doesn't manage anymore __stack_chk_guard as > > a global variable but as some value located at -0x7008(r2) > > Is this still an "RFC" or is there a chance that this will land in 4.10? Older GCC (i.e. not ancient, but < 7 currently; the new options will be backported to 5 and 6) doesn't always use TLS stack canaries either: it depends on how your GCC is configured. The kernel will have to detect if the GCC it uses knows the new options, and if not, if it still wants to use SSP it has to detect what GCC uses to get at the canary. This patch as-is won't work. Segher
Christian Kujau <lists@nerdbynature.de> writes: > On Mon, 16 Jan 2017, Christophe Leroy wrote: >> Since 2005, powerpc GCC doesn't manage anymore __stack_chk_guard as >> a global variable but as some value located at -0x7008(r2) > > Is this still an "RFC" or is there a chance that this will land in 4.10? No. I've reverted the stack protector support in my fixes branch (which is in linux-next), and it will go into 4.10 this week. cheers
diff --git a/arch/powerpc/include/asm/current.h b/arch/powerpc/include/asm/current.h index e2c7f06..2f67f02 100644 --- a/arch/powerpc/include/asm/current.h +++ b/arch/powerpc/include/asm/current.h @@ -27,8 +27,16 @@ static inline struct task_struct *get_current(void) } #define current get_current() -#else +#else /* __powerpc64__ */ +#if defined(CONFIG_CC_STACKPROTECTOR) +#include <linux/thread_info.h> +static inline struct task_struct *get_current(void) +{ + return current_thread_info()->task; +} +#define current get_current() +#else /* * We keep `current' in r2 for speed. */ @@ -36,5 +44,7 @@ register struct task_struct *current asm ("r2"); #endif +#endif /* __powerpc64__ */ + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_CURRENT_H */ diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h index 6720190..bf30509 100644 --- a/arch/powerpc/include/asm/stackprotector.h +++ b/arch/powerpc/include/asm/stackprotector.h @@ -12,12 +12,18 @@ #ifndef _ASM_STACKPROTECTOR_H #define _ASM_STACKPROTECTOR_H +#ifdef CONFIG_PPC64 +#define SSP_OFFSET 0x7010 +#else +#define SSP_OFFSET 0x7008 +#endif + +#ifndef __ASSEMBLY__ + #include <linux/random.h> #include <linux/version.h> #include <asm/reg.h> -extern unsigned long __stack_chk_guard; - /* * Initialize the stackprotector canary value. * @@ -34,7 +40,6 @@ static __always_inline void boot_init_stack_canary(void) canary ^= LINUX_VERSION_CODE; current->stack_canary = canary; - __stack_chk_guard = current->stack_canary; } - +#endif /* __ASSEMBLY__ */ #endif /* _ASM_STACKPROTECTOR_H */ diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 5742dbd..b3a363c 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -34,6 +34,7 @@ #include <asm/ftrace.h> #include <asm/ptrace.h> #include <asm/export.h> +#include <asm/stackprotector.h> /* * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. @@ -149,6 +150,9 @@ transfer_to_handler: mfspr r12,SPRN_SPRG_THREAD addi r2,r12,-THREAD tovirt(r2,r2) /* set r2 to current */ +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif beq 2f /* if from user, fix up THREAD.regs */ addi r11,r1,STACK_FRAME_OVERHEAD stw r11,PT_REGS(r12) @@ -385,6 +389,9 @@ syscall_exit_cont: lwz r3,GPR3(r1) 1: #endif /* CONFIG_TRACE_IRQFLAGS */ +#if defined(CONFIG_CC_STACKPROTECTOR) + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* If the process has its own DBCR0 value, load it up. The internal debug mode bit tells us that dbcr0 should be loaded. */ @@ -617,6 +624,9 @@ _GLOBAL(_switch) stwu r1,-INT_FRAME_SIZE(r1) mflr r0 stw r0,INT_FRAME_SIZE+4(r1) +#if defined(CONFIG_CC_STACKPROTECTOR) + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* r3-r12 are caller saved -- Cort */ SAVE_NVGPRS(r1) stw r0,_NIP(r1) /* Return to switch caller */ @@ -674,10 +684,8 @@ BEGIN_FTR_SECTION mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */ END_FTR_SECTION_IFSET(CPU_FTR_SPE) #endif /* CONFIG_SPE */ -#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) - lwz r0,TSK_STACK_CANARY(r2) - lis r4,__stack_chk_guard@ha - stw r0,__stack_chk_guard@l(r4) +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET #endif lwz r0,_CCR(r1) mtcrf 0xFF,r0 @@ -779,6 +787,9 @@ user_exc_return: /* r10 contains MSR_KERNEL here */ bne do_work restore_user: +#if defined(CONFIG_CC_STACKPROTECTOR) + subi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* Check whether this process has its own DBCR0 value. The internal debug mode bit tells us that dbcr0 should be loaded. */ diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 9d96354..bae9b83 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -35,6 +35,7 @@ #include <asm/bug.h> #include <asm/kvm_book3s_asm.h> #include <asm/export.h> +#include <asm/stackprotector.h> /* 601 only have IBAT; cr0.eq is set on 601 when using this macro */ #define LOAD_BAT(n, reg, RA, RB) \ @@ -864,6 +865,9 @@ __secondary_start: tophys(r4,r2) addi r4,r4,THREAD /* phys address of our thread_struct */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif li r3,0 mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */ @@ -950,6 +954,9 @@ start_here: tophys(r4,r2) addi r4,r4,THREAD /* init task's THREAD */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif li r3,0 mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */ diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S index 41374a4..20b1c31 100644 --- a/arch/powerpc/kernel/head_40x.S +++ b/arch/powerpc/kernel/head_40x.S @@ -42,6 +42,7 @@ #include <asm/asm-offsets.h> #include <asm/ptrace.h> #include <asm/export.h> +#include <asm/stackprotector.h> /* As with the other PowerPC ports, it is expected that when code * execution begins here, the following registers contain valid, yet @@ -835,6 +836,9 @@ start_here: tophys(r4,r2) addi r4,r4,THREAD /* init task's THREAD */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* stack */ lis r1,init_thread_union@ha diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S index 37e4a7c..753e2bf 100644 --- a/arch/powerpc/kernel/head_44x.S +++ b/arch/powerpc/kernel/head_44x.S @@ -40,6 +40,7 @@ #include <asm/ptrace.h> #include <asm/synch.h> #include <asm/export.h> +#include <asm/stackprotector.h> #include "head_booke.h" @@ -107,6 +108,9 @@ _ENTRY(_start); /* ptr to current thread */ addi r4,r2,THREAD /* init task's THREAD */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* stack */ lis r1,init_thread_union@h diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 1a9c99d..49f9ce1 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -32,6 +32,7 @@ #include <asm/ptrace.h> #include <asm/fixmap.h> #include <asm/export.h> +#include <asm/stackprotector.h> /* Macro to make the code more readable. */ #ifdef CONFIG_8xx_CPU6 @@ -820,6 +821,9 @@ start_here: tophys(r4,r2) addi r4,r4,THREAD /* init task's THREAD */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* stack */ lis r1,init_thread_union@ha diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S index bf4c602..9634ac7 100644 --- a/arch/powerpc/kernel/head_fsl_booke.S +++ b/arch/powerpc/kernel/head_fsl_booke.S @@ -43,6 +43,7 @@ #include <asm/cache.h> #include <asm/ptrace.h> #include <asm/export.h> +#include <asm/stackprotector.h> #include "head_booke.h" /* As with the other PowerPC ports, it is expected that when code @@ -235,6 +236,9 @@ set_ivor: /* ptr to current thread */ addi r4,r2,THREAD /* init task's THREAD */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* stack */ lis r1,init_thread_union@h @@ -1086,6 +1090,9 @@ __secondary_start: /* ptr to current thread */ addi r4,r2,THREAD /* address of our thread_struct */ mtspr SPRN_SPRG_THREAD,r4 +#if defined(CONFIG_CC_STACKPROTECTOR) + addi r2,r2,TSK_STACK_CANARY+SSP_OFFSET +#endif /* Setup the defaults for TLB entries */ li r4,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 04885ce..5dd056d 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -64,12 +64,6 @@ #include <linux/kprobes.h> #include <linux/kdebug.h> -#ifdef CONFIG_CC_STACKPROTECTOR -#include <linux/stackprotector.h> -unsigned long __stack_chk_guard __read_mostly; -EXPORT_SYMBOL(__stack_chk_guard); -#endif - /* Transactional Memory debug */ #ifdef TM_DEBUG_SW #define TM_DEBUG(x...) printk(KERN_INFO x)
Since 2005, powerpc GCC doesn't manage anymore __stack_chk_guard as a global variable but as some value located at -0x7008(r2) In the Linux kernel, r2 is used as a pointer to current task struct. This patch changes the meaning of r2 when stack protector is activated: - current is taken from thread_info and not kept in r2 anymore - r2 is set to current + offset of stack canary + 0x7008 so that -0x7008(r2) directly points to current->stack_canary current could have been more efficiently calculated from r2 but some circular inclusion prevent inserting struct task_struct into arch/powerpc/include/asm/current.h so it is not possible to get offset of stack_canary within current task_struct from there. fixes: 6533b7c16ee57 ("powerpc: Initial stack protector (-fstack-protector) support") Reported-by: Christian Kujau <lists@nerdbynature.de> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- Christian, can you test it ? arch/powerpc/include/asm/current.h | 12 +++++++++++- arch/powerpc/include/asm/stackprotector.h | 13 +++++++++---- arch/powerpc/kernel/entry_32.S | 19 +++++++++++++++---- arch/powerpc/kernel/head_32.S | 7 +++++++ arch/powerpc/kernel/head_40x.S | 4 ++++ arch/powerpc/kernel/head_44x.S | 4 ++++ arch/powerpc/kernel/head_8xx.S | 4 ++++ arch/powerpc/kernel/head_fsl_booke.S | 7 +++++++ arch/powerpc/kernel/process.c | 6 ------ 9 files changed, 61 insertions(+), 15 deletions(-)