diff --git a/arch/arm/include/asm/ucontext.h b/arch/arm/include/asm/ucontext.h index 921d8274855c..b42c75ae0d19 100644 --- a/arch/arm/include/asm/ucontext.h +++ b/arch/arm/include/asm/ucontext.h @@ -2,6 +2,7 @@ #define _ASMARM_UCONTEXT_H #include +#include /* * struct sigcontext only has room for the basic registers, but struct diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 608008229c7d..13c155850822 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -28,6 +28,7 @@ #include #include #include +#include "signal.h" /* * Make sure that the compiler and target are compatible. @@ -112,6 +113,9 @@ int main(void) DEFINE(SVC_ADDR_LIMIT, offsetof(struct svc_pt_regs, addr_limit)); DEFINE(SVC_REGS_SIZE, sizeof(struct svc_pt_regs)); BLANK(); + DEFINE(SIGFRAME_RC3_OFFSET, offsetof(struct sigframe, retcode[3])); + DEFINE(RT_SIGFRAME_RC3_OFFSET, offsetof(struct rt_sigframe, sig.retcode[3])); + BLANK(); #ifdef CONFIG_CACHE_L2X0 DEFINE(L2X0_R_PHY_BASE, offsetof(struct l2x0_regs, phy_base)); DEFINE(L2X0_R_AUX_CTRL, offsetof(struct l2x0_regs, aux_ctrl)); diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 5814298ef0b7..1f3574ec4fad 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -18,11 +18,12 @@ #include #include #include -#include #include #include -extern const unsigned long sigreturn_codes[7]; +#include "signal.h" + +extern const unsigned long sigreturn_codes[17]; static unsigned long signal_return_offset; @@ -171,15 +172,6 @@ static int restore_vfp_context(char __user **auxp) /* * Do a signal return; undo the signal stack. These are aligned to 64-bit. */ -struct sigframe { - struct ucontext uc; - unsigned long retcode[2]; -}; - -struct rt_sigframe { - struct siginfo info; - struct sigframe sig; -}; static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) { @@ -365,9 +357,20 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, unsigned long __user *rc, void __user *frame) { unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler; + unsigned long handler_fdpic_GOT = 0; unsigned long retcode; - int thumb = 0; + unsigned int idx, thumb = 0; unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); + bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) && + (current->personality & FDPIC_FUNCPTRS); + + if (fdpic) { + unsigned long __user *fdpic_func_desc = + (unsigned long __user *)handler; + if (__get_user(handler, &fdpic_func_desc[0]) || + __get_user(handler_fdpic_GOT, &fdpic_func_desc[1])) + return 1; + } cpsr |= PSR_ENDSTATE; @@ -407,9 +410,26 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, if (ksig->ka.sa.sa_flags & SA_RESTORER) { retcode = (unsigned long)ksig->ka.sa.sa_restorer; + if (fdpic) { + /* + * We need code to load the function descriptor. + * That code follows the standard sigreturn code + * (6 words), and is made of 3 + 2 words for each + * variant. The 4th copied word is the actual FD + * address that the assembly code expects. + */ + idx = 6 + thumb * 3; + if (ksig->ka.sa.sa_flags & SA_SIGINFO) + idx += 5; + if (__put_user(sigreturn_codes[idx], rc ) || + __put_user(sigreturn_codes[idx+1], rc+1) || + __put_user(sigreturn_codes[idx+2], rc+2) || + __put_user(retcode, rc+3)) + return 1; + goto rc_finish; + } } else { - unsigned int idx = thumb << 1; - + idx = thumb << 1; if (ksig->ka.sa.sa_flags & SA_SIGINFO) idx += 3; @@ -421,6 +441,7 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, __put_user(sigreturn_codes[idx+1], rc+1)) return 1; +rc_finish: #ifdef CONFIG_MMU if (cpsr & MODE32_BIT) { struct mm_struct *mm = current->mm; @@ -440,7 +461,7 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, * the return code written onto the stack. */ flush_icache_range((unsigned long)rc, - (unsigned long)(rc + 2)); + (unsigned long)(rc + 3)); retcode = ((unsigned long)rc) + thumb; } @@ -450,6 +471,8 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, regs->ARM_sp = (unsigned long)frame; regs->ARM_lr = retcode; regs->ARM_pc = handler; + if (fdpic) + regs->ARM_r9 = handler_fdpic_GOT; regs->ARM_cpsr = cpsr; return 0; diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h new file mode 100644 index 000000000000..b7b838b05229 --- /dev/null +++ b/arch/arm/kernel/signal.h @@ -0,0 +1,11 @@ +#include + +struct sigframe { + struct ucontext uc; + unsigned long retcode[4]; +}; + +struct rt_sigframe { + struct siginfo info; + struct sigframe sig; +}; diff --git a/arch/arm/kernel/sigreturn_codes.S b/arch/arm/kernel/sigreturn_codes.S index b84d0cb13682..2c7b22e32152 100644 --- a/arch/arm/kernel/sigreturn_codes.S +++ b/arch/arm/kernel/sigreturn_codes.S @@ -14,6 +14,8 @@ * GNU General Public License for more details. */ +#include +#include #include /* @@ -51,6 +53,17 @@ ARM_OK( .arm ) .thumb .endm + .macro arm_fdpic_slot n + .org sigreturn_codes + 24 + 20 * (\n) +ARM_OK( .arm ) + .endm + + .macro thumb_fdpic_slot n + .org sigreturn_codes + 24 + 20 * (\n) + 12 + .thumb + .endm + + #if __LINUX_ARM_ARCH__ <= 4 /* * Note we manually set minimally required arch that supports @@ -90,13 +103,46 @@ ARM_OK( swi #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE) ) movs r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE) swi #0 + /* ARM sigreturn restorer FDPIC bounce code snippet */ + arm_fdpic_slot 0 +ARM_OK( ldr r3, [sp, #SIGFRAME_RC3_OFFSET] ) +ARM_OK( ldmia r3, {r3, r9} ) +#ifdef CONFIG_ARM_THUMB +ARM_OK( bx r3 ) +#else +ARM_OK( ret r3 ) +#endif + + /* Thumb sigreturn restorer FDPIC bounce code snippet */ + thumb_fdpic_slot 0 + ldr r3, [sp, #SIGFRAME_RC3_OFFSET] + ldmia r3, {r2, r3} + mov r9, r3 + bx r2 + + /* ARM sigreturn_rt restorer FDPIC bounce code snippet */ + arm_fdpic_slot 1 +ARM_OK( ldr r3, [sp, #RT_SIGFRAME_RC3_OFFSET] ) +ARM_OK( ldmia r3, {r3, r9} ) +#ifdef CONFIG_ARM_THUMB +ARM_OK( bx r3 ) +#else +ARM_OK( ret r3 ) +#endif + + /* Thumb sigreturn_rt restorer FDPIC bounce code snippet */ + thumb_fdpic_slot 1 + ldr r3, [sp, #RT_SIGFRAME_RC3_OFFSET] + ldmia r3, {r2, r3} + mov r9, r3 + bx r2 + /* - * Note on addtional space: setup_return in signal.c - * algorithm uses two words copy regardless whether - * it is thumb case or not, so we need additional - * word after real last entry. + * Note on additional space: setup_return in signal.c + * always copies the same number of words regardless whether + * it is thumb case or not, so we need one additional padding + * word after the last entry. */ - arm_slot 2 .space 4 .size sigreturn_codes, . - sigreturn_codes