From 63ae2a94d98dd9d94163918539ec80df33f44a69 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 27 Mar 2006 01:14:30 -0800 Subject: [PATCH] uml: move libc-dependent irq code to os-Linux The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from irq_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/sys-i386/user-offsets.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/um/sys-i386') diff --git a/arch/um/sys-i386/user-offsets.c b/arch/um/sys-i386/user-offsets.c index 26b68675053d..6f4ef2b7fa4a 100644 --- a/arch/um/sys-i386/user-offsets.c +++ b/arch/um/sys-i386/user-offsets.c @@ -3,12 +3,13 @@ #include #include #include +#include #define DEFINE(sym, val) \ - asm volatile("\n->" #sym " %0 " #val : : "i" (val)) + asm volatile("\n->" #sym " %0 " #val : : "i" (val)) #define DEFINE_LONGS(sym, val) \ - asm volatile("\n->" #sym " %0 " #val : : "i" (val/sizeof(unsigned long))) + asm volatile("\n->" #sym " %0 " #val : : "i" (val/sizeof(unsigned long))) #define OFFSET(sym, str, mem) \ DEFINE(sym, offsetof(struct str, mem)); @@ -67,4 +68,9 @@ void foo(void) DEFINE(HOST_ES, ES); DEFINE(HOST_GS, GS); DEFINE(UM_FRAME_SIZE, sizeof(struct user_regs_struct)); + + /* XXX Duplicated between i386 and x86_64 */ + DEFINE(UM_POLLIN, POLLIN); + DEFINE(UM_POLLPRI, POLLPRI); + DEFINE(UM_POLLOUT, POLLOUT); } -- cgit v1.2.3 From 81efcd3300754462537ffac60336158b2f773b4e Mon Sep 17 00:00:00 2001 From: Bodo Stroesser Date: Mon, 27 Mar 2006 01:14:34 -0800 Subject: [PATCH] uml: more carefully test whether we are in a system call For security reasons, UML in is_syscall() needs to have access to code in vsyscall-page. The current implementation grants this access by explicitly allowing access to vsyscall in access_ok_skas(). With this change, copy_from_user() may be used to read the code. Ptrace access to vsyscall-page for debugging already was implemented in get_user_pages() by mainline. In i386, copy_from_user can't access vsyscall-page, but returns EFAULT. To make UML behave as i386 does, I changed is_syscall to use access_process_vm(current) to read the code from vsyscall-page. This doesn't hurt security, but simplifies the code and prepares implementation of stub-vmas. Signed-off-by: Bodo Stroesser Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/sys-i386/ptrace.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'arch/um/sys-i386') diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c index e839ce65ad28..8032a105949a 100644 --- a/arch/um/sys-i386/ptrace.c +++ b/arch/um/sys-i386/ptrace.c @@ -6,6 +6,7 @@ #include #include #include "linux/sched.h" +#include "linux/mm.h" #include "asm/elf.h" #include "asm/ptrace.h" #include "asm/uaccess.h" @@ -26,9 +27,17 @@ int is_syscall(unsigned long addr) n = copy_from_user(&instr, (void __user *) addr, sizeof(instr)); if(n){ - printk("is_syscall : failed to read instruction from 0x%lx\n", - addr); - return(0); + /* access_process_vm() grants access to vsyscall and stub, + * while copy_from_user doesn't. Maybe access_process_vm is + * slow, but that doesn't matter, since it will be called only + * in case of singlestepping, if copy_from_user failed. + */ + n = access_process_vm(current, addr, &instr, sizeof(instr), 0); + if(n != sizeof(instr)) { + printk("is_syscall : failed to read instruction from " + "0x%lx\n", addr); + return(1); + } } /* int 0x80 or sysenter */ return((instr == 0x80cd) || (instr == 0x340f)); -- cgit v1.2.3 From 98c18238f146a9038098244d60a7d2b1f67ee790 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Mon, 27 Mar 2006 01:14:38 -0800 Subject: [PATCH] uml: fix segfault on signal delivery This fixes a process segfault where a signal was being delivered such that a new stack page needed to be allocated to hold the signal frame. This was tripping some logic in the page fault handler which wouldn't allocate the page if the faulting address was more that 32 bytes lower than the current stack pointer. Since a signal frame is greater than 32 bytes, this exercised that case. It's fixed by updating the SP in the pt_regs before starting to copy the signal frame. Since those are the registers that will be copied on to the stack, we have to be careful to put the original SP, not the new one which points to the signal frame, on the stack. Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/sys-i386/signal.c | 59 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 44 insertions(+), 15 deletions(-) (limited to 'arch/um/sys-i386') diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c index 7cd1a82dc8c2..33a40f5ef0d2 100644 --- a/arch/um/sys-i386/signal.c +++ b/arch/um/sys-i386/signal.c @@ -58,7 +58,7 @@ static int copy_sc_from_user_skas(struct pt_regs *regs, } int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp, - struct pt_regs *regs) + struct pt_regs *regs, unsigned long sp) { struct sigcontext sc; unsigned long fpregs[HOST_FP_SIZE]; @@ -72,7 +72,7 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp, sc.edi = REGS_EDI(regs->regs.skas.regs); sc.esi = REGS_ESI(regs->regs.skas.regs); sc.ebp = REGS_EBP(regs->regs.skas.regs); - sc.esp = REGS_SP(regs->regs.skas.regs); + sc.esp = sp; sc.ebx = REGS_EBX(regs->regs.skas.regs); sc.edx = REGS_EDX(regs->regs.skas.regs); sc.ecx = REGS_ECX(regs->regs.skas.regs); @@ -132,7 +132,7 @@ int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from, } int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp, - struct sigcontext *from, int fpsize) + struct sigcontext *from, int fpsize, unsigned long sp) { struct _fpstate *to_fp, *from_fp; int err; @@ -140,11 +140,18 @@ int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp, to_fp = (fp ? fp : (struct _fpstate *) (to + 1)); from_fp = from->fpstate; err = copy_to_user(to, from, sizeof(*to)); + + /* The SP in the sigcontext is the updated one for the signal + * delivery. The sp passed in is the original, and this needs + * to be restored, so we stick it in separately. + */ + err |= copy_to_user(&SC_SP(to), sp, sizeof(sp)); + if(from_fp != NULL){ err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate)); err |= copy_to_user(to_fp, from_fp, fpsize); } - return(err); + return err; } #endif @@ -159,11 +166,11 @@ static int copy_sc_from_user(struct pt_regs *to, void __user *from) } static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp, - struct pt_regs *from) + struct pt_regs *from, unsigned long sp) { return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs), - sizeof(*fp)), - copy_sc_to_user_skas(to, fp, from))); + sizeof(*fp), sp), + copy_sc_to_user_skas(to, fp, from, sp))); } static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp, @@ -174,7 +181,7 @@ static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp, err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp); err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags); err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size); - err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs); + err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, sp); err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); return(err); } @@ -207,6 +214,7 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig, { struct sigframe __user *frame; void *restorer; + unsigned long save_sp = PT_REGS_SP(regs); int err = 0; stack_top &= -8UL; @@ -218,9 +226,19 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig, if(ka->sa.sa_flags & SA_RESTORER) restorer = ka->sa.sa_restorer; + /* Update SP now because the page fault handler refuses to extend + * the stack if the faulting address is too far below the current + * SP, which frame now certainly is. If there's an error, the original + * value is restored on the way out. + * When writing the sigcontext to the stack, we have to write the + * original value, so that's passed to copy_sc_to_user, which does + * the right thing with it. + */ + PT_REGS_SP(regs) = (unsigned long) frame; + err |= __put_user(restorer, &frame->pretcode); err |= __put_user(sig, &frame->sig); - err |= copy_sc_to_user(&frame->sc, NULL, regs); + err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp); err |= __put_user(mask->sig[0], &frame->sc.oldmask); if (_NSIG_WORDS > 1) err |= __copy_to_user(&frame->extramask, &mask->sig[1], @@ -238,7 +256,7 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig, err |= __put_user(0x80cd, (short __user *)(frame->retcode+6)); if(err) - return(err); + goto err; PT_REGS_SP(regs) = (unsigned long) frame; PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; @@ -248,7 +266,11 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig, if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED)) ptrace_notify(SIGTRAP); - return(0); + return 0; + +err: + PT_REGS_SP(regs) = save_sp; + return err; } int setup_signal_stack_si(unsigned long stack_top, int sig, @@ -257,6 +279,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, { struct rt_sigframe __user *frame; void *restorer; + unsigned long save_sp = PT_REGS_SP(regs); int err = 0; stack_top &= -8UL; @@ -268,13 +291,16 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, if(ka->sa.sa_flags & SA_RESTORER) restorer = ka->sa.sa_restorer; + /* See comment above about why this is here */ + PT_REGS_SP(regs) = (unsigned long) frame; + err |= __put_user(restorer, &frame->pretcode); err |= __put_user(sig, &frame->sig); err |= __put_user(&frame->info, &frame->pinfo); err |= __put_user(&frame->uc, &frame->puc); err |= copy_siginfo_to_user(&frame->info, info); err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask, - PT_REGS_SP(regs)); + save_sp); /* * This is movl $,%eax ; int $0x80 @@ -288,9 +314,8 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, err |= __put_user(0x80cd, (short __user *)(frame->retcode+5)); if(err) - return(err); + goto err; - PT_REGS_SP(regs) = (unsigned long) frame; PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; PT_REGS_EAX(regs) = (unsigned long) sig; PT_REGS_EDX(regs) = (unsigned long) &frame->info; @@ -298,7 +323,11 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED)) ptrace_notify(SIGTRAP); - return(0); + return 0; + +err: + PT_REGS_SP(regs) = save_sp; + return err; } long sys_sigreturn(struct pt_regs regs) -- cgit v1.2.3