diff options
Diffstat (limited to 'arch/um/os-Linux/skas/process.c')
-rw-r--r-- | arch/um/os-Linux/skas/process.c | 281 |
1 files changed, 186 insertions, 95 deletions
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index e8b7a97..d36c89c 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -15,6 +15,7 @@ #include "as-layout.h" #include "chan_user.h" #include "kern_constants.h" +#include "kern_util.h" #include "mem.h" #include "os.h" #include "process.h" @@ -37,27 +38,27 @@ int is_skas_winch(int pid, int fd, void *data) static int ptrace_dump_regs(int pid) { - unsigned long regs[MAX_REG_NR]; - int i; + unsigned long regs[MAX_REG_NR]; + int i; - if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) - return -errno; + if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) + return -errno; printk(UM_KERN_ERR "Stub registers -\n"); for (i = 0; i < ARRAY_SIZE(regs); i++) printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]); - return 0; + return 0; } /* * Signals that are OK to receive in the stub - we'll just continue it. * SIGWINCH will happen when UML is inside a detached screen. */ -#define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH)) +#define STUB_SIG_MASK (1 << SIGVTALRM) /* Signals that the stub will finish with - anything else is an error */ -#define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP)) +#define STUB_DONE_MASK (1 << SIGTRAP) void wait_stub_done(int pid) { @@ -72,9 +73,11 @@ void wait_stub_done(int pid) break; err = ptrace(PTRACE_CONT, pid, 0, 0); - if (err) - panic("wait_stub_done : continue failed, errno = %d\n", - errno); + if (err) { + printk(UM_KERN_ERR "wait_stub_done : continue failed, " + "errno = %d\n", errno); + fatal_sigsegv(); + } } if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0) @@ -85,8 +88,10 @@ bad_wait: if (err) printk(UM_KERN_ERR "Failed to get registers from stub, " "errno = %d\n", -err); - panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, " - "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status); + printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, " + "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno, + status); + fatal_sigsegv(); } extern unsigned long current_stub_stack(void); @@ -97,9 +102,11 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi) if (ptrace_faultinfo) { err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); - if (err) - panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " - "errno = %d\n", errno); + if (err) { + printk(UM_KERN_ERR "get_skas_faultinfo - " + "PTRACE_FAULTINFO failed, errno = %d\n", errno); + fatal_sigsegv(); + } /* Special handling for i386, which has different structs */ if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) @@ -109,9 +116,11 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi) } else { err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV); - if (err) - panic("Failed to continue stub, pid = %d, errno = %d\n", - pid, errno); + if (err) { + printk(UM_KERN_ERR "Failed to continue stub, pid = %d, " + "errno = %d\n", pid, errno); + fatal_sigsegv(); + } wait_stub_done(pid); /* @@ -137,6 +146,9 @@ static void handle_trap(int pid, struct uml_pt_regs *regs, { int err, status; + if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END)) + fatal_sigsegv(); + /* Mark this as a syscall */ UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp); @@ -144,25 +156,31 @@ static void handle_trap(int pid, struct uml_pt_regs *regs, { err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); - if (err < 0) - panic("handle_trap - nullifying syscall failed, " - "errno = %d\n", errno); + if (err < 0) { + printk(UM_KERN_ERR "handle_trap - nullifying syscall " + "failed, errno = %d\n", errno); + fatal_sigsegv(); + } err = ptrace(PTRACE_SYSCALL, pid, 0, 0); - if (err < 0) - panic("handle_trap - continuing to end of syscall " - "failed, errno = %d\n", errno); + if (err < 0) { + printk(UM_KERN_ERR "handle_trap - continuing to end of " + "syscall failed, errno = %d\n", errno); + fatal_sigsegv(); + } CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); if ((err < 0) || !WIFSTOPPED(status) || - (WSTOPSIG(status) != SIGTRAP + 0x80)) { - err = ptrace_dump_regs(pid); - if (err) - printk(UM_KERN_ERR "Failed to get registers " + (WSTOPSIG(status) != SIGTRAP + 0x80)) { + err = ptrace_dump_regs(pid); + if (err) + printk(UM_KERN_ERR "Failed to get registers " "from process, errno = %d\n", -err); - panic("handle_trap - failed to wait at end of syscall, " - "errno = %d, status = %d\n", errno, status); - } + printk(UM_KERN_ERR "handle_trap - failed to wait at " + "end of syscall, errno = %d, status = %d\n", + errno, status); + fatal_sigsegv(); + } } handle_syscall(regs); @@ -178,10 +196,13 @@ static int userspace_tramp(void *stack) ptrace(PTRACE_TRACEME, 0, 0, 0); signal(SIGTERM, SIG_DFL); + signal(SIGWINCH, SIG_IGN); err = set_interval(); - if (err) - panic("userspace_tramp - setting timer failed, errno = %d\n", - err); + if (err) { + printk(UM_KERN_ERR "userspace_tramp - setting timer failed, " + "errno = %d\n", err); + exit(1); + } if (!proc_mm) { /* @@ -221,16 +242,14 @@ static int userspace_tramp(void *stack) set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE); sigemptyset(&sa.sa_mask); - sigaddset(&sa.sa_mask, SIGIO); - sigaddset(&sa.sa_mask, SIGWINCH); - sigaddset(&sa.sa_mask, SIGVTALRM); - sigaddset(&sa.sa_mask, SIGUSR1); - sa.sa_flags = SA_ONSTACK; + sa.sa_flags = SA_ONSTACK | SA_NODEFER; sa.sa_handler = (void *) v; sa.sa_restorer = NULL; - if (sigaction(SIGSEGV, &sa, NULL) < 0) - panic("userspace_tramp - setting SIGSEGV handler " - "failed - errno = %d\n", errno); + if (sigaction(SIGSEGV, &sa, NULL) < 0) { + printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV " + "handler failed - errno = %d\n", errno); + exit(1); + } } kill(os_getpid(), SIGSTOP); @@ -246,13 +265,18 @@ int start_userspace(unsigned long stub_stack) { void *stack; unsigned long sp; - int pid, status, n, flags; + int pid, status, n, flags, err; stack = mmap(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (stack == MAP_FAILED) - panic("start_userspace : mmap failed, errno = %d", errno); + if (stack == MAP_FAILED) { + err = -errno; + printk(UM_KERN_ERR "start_userspace : mmap failed, " + "errno = %d\n", errno); + return err; + } + sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *); flags = CLONE_FILES; @@ -262,29 +286,50 @@ int start_userspace(unsigned long stub_stack) flags |= SIGCHLD; pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); - if (pid < 0) - panic("start_userspace : clone failed, errno = %d", errno); + if (pid < 0) { + err = -errno; + printk(UM_KERN_ERR "start_userspace : clone failed, " + "errno = %d\n", errno); + return err; + } do { CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); - if (n < 0) - panic("start_userspace : wait failed, errno = %d", - errno); + if (n < 0) { + err = -errno; + printk(UM_KERN_ERR "start_userspace : wait failed, " + "errno = %d\n", errno); + goto out_kill; + } } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); - if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) - panic("start_userspace : expected SIGSTOP, got status = %d", - status); + if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) { + err = -EINVAL; + printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got " + "status = %d\n", status); + goto out_kill; + } if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, - (void *) PTRACE_O_TRACESYSGOOD) < 0) - panic("start_userspace : PTRACE_OLDSETOPTIONS failed, " - "errno = %d\n", errno); + (void *) PTRACE_O_TRACESYSGOOD) < 0) { + err = -errno; + printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS " + "failed, errno = %d\n", errno); + goto out_kill; + } - if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) - panic("start_userspace : munmap failed, errno = %d\n", errno); + if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) { + err = -errno; + printk(UM_KERN_ERR "start_userspace : munmap failed, " + "errno = %d\n", errno); + goto out_kill; + } return pid; + + out_kill: + os_kill_ptraced_process(pid, 1); + return err; } void userspace(struct uml_pt_regs *regs) @@ -302,7 +347,16 @@ void userspace(struct uml_pt_regs *regs) nsecs += os_nsecs(); while (1) { - restore_registers(pid, regs); + /* + * This can legitimately fail if the process loads a + * bogus value into a segment register. It will + * segfault and PTRACE_GETREGS will read that value + * out of the process. However, PTRACE_SETREGS will + * fail. In this case, there is nothing to do but + * just kill the process. + */ + if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) + fatal_sigsegv(); /* Now we set local_using_sysemu to be used for one loop */ local_using_sysemu = get_using_sysemu(); @@ -310,19 +364,26 @@ void userspace(struct uml_pt_regs *regs) op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); - err = ptrace(op, pid, 0, 0); - if (err) - panic("userspace - could not resume userspace process, " - "pid=%d, ptrace operation = %d, errno = %d\n", - pid, op, errno); + if (ptrace(op, pid, 0, 0)) { + printk(UM_KERN_ERR "userspace - ptrace continue " + "failed, op = %d, errno = %d\n", op, errno); + fatal_sigsegv(); + } CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); - if (err < 0) - panic("userspace - waitpid failed, errno = %d\n", - errno); + if (err < 0) { + printk(UM_KERN_ERR "userspace - wait failed, " + "errno = %d\n", errno); + fatal_sigsegv(); + } regs->is_user = 1; - save_registers(pid, regs); + if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) { + printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, " + "errno = %d\n", errno); + fatal_sigsegv(); + } + UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ if (WIFSTOPPED(status)) { @@ -345,7 +406,7 @@ void userspace(struct uml_pt_regs *regs) break; case SIGVTALRM: now = os_nsecs(); - if(now < nsecs) + if (now < nsecs) break; block_signals(); (*sig_info[sig])(sig, regs); @@ -368,6 +429,7 @@ void userspace(struct uml_pt_regs *regs) default: printk(UM_KERN_ERR "userspace - child stopped " "with signal %d\n", sig); + fatal_sigsegv(); } pid = userspace_pid[0]; interrupt_end(); @@ -419,9 +481,12 @@ int copy_context_skas0(unsigned long new_stack, int pid) .it_interval = tv }) }); err = ptrace_setregs(pid, thread_regs); - if (err < 0) - panic("copy_context_skas0 : PTRACE_SETREGS failed, " - "pid = %d, errno = %d\n", pid, -err); + if (err < 0) { + err = -errno; + printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS " + "failed, pid = %d, errno = %d\n", pid, -err); + return err; + } /* set a well known return code for detection of child write failure */ child_data->err = 12345678; @@ -431,31 +496,47 @@ int copy_context_skas0(unsigned long new_stack, int pid) * parent's stack, and check, if bad result. */ err = ptrace(PTRACE_CONT, pid, 0, 0); - if (err) - panic("Failed to continue new process, pid = %d, " - "errno = %d\n", pid, errno); + if (err) { + err = -errno; + printk(UM_KERN_ERR "Failed to continue new process, pid = %d, " + "errno = %d\n", pid, errno); + return err; + } + wait_stub_done(pid); pid = data->err; - if (pid < 0) - panic("copy_context_skas0 - stub-parent reports error %d\n", - -pid); + if (pid < 0) { + printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports " + "error %d\n", -pid); + return pid; + } /* * Wait, until child has finished too: read child's result from * child's stack and check it. */ wait_stub_done(pid); - if (child_data->err != STUB_DATA) - panic("copy_context_skas0 - stub-child reports error %ld\n", - child_data->err); + if (child_data->err != STUB_DATA) { + printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports " + "error %ld\n", child_data->err); + err = child_data->err; + goto out_kill; + } if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, - (void *)PTRACE_O_TRACESYSGOOD) < 0) - panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, " - "errno = %d\n", errno); + (void *)PTRACE_O_TRACESYSGOOD) < 0) { + err = -errno; + printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS " + "failed, errno = %d\n", errno); + goto out_kill; + } return pid; + + out_kill: + os_kill_ptraced_process(pid, 1); + return err; } /* @@ -463,8 +544,8 @@ int copy_context_skas0(unsigned long new_stack, int pid) * available. Opening /proc/mm creates a new mm_context, which lacks * the stub-pages. Thus, we map them using /proc/mm-fd */ -void map_stub_pages(int fd, unsigned long code, - unsigned long data, unsigned long stack) +int map_stub_pages(int fd, unsigned long code, unsigned long data, + unsigned long stack) { struct proc_mm_op mmop; int n; @@ -488,8 +569,9 @@ void map_stub_pages(int fd, unsigned long code, printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, " "offset = %llx\n", code, code_fd, (unsigned long long) code_offset); - panic("map_stub_pages : /proc/mm map for code failed, " - "err = %d\n", n); + printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for code " + "failed, err = %d\n", n); + return -n; } if (stack) { @@ -507,10 +589,15 @@ void map_stub_pages(int fd, unsigned long code, .offset = map_offset } } }); CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop))); - if (n != sizeof(mmop)) - panic("map_stub_pages : /proc/mm map for data failed, " - "err = %d\n", errno); + if (n != sizeof(mmop)) { + n = errno; + printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for " + "data failed, err = %d\n", n); + return -n; + } } + + return 0; } void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)) @@ -571,7 +658,9 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf) kmalloc_ok = 0; return 1; default: - panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); + printk(UM_KERN_ERR "Bad sigsetjmp return in " + "start_idle_thread - %d\n", n); + fatal_sigsegv(); } longjmp(*switch_buf, 1); } @@ -614,9 +703,11 @@ void __switch_mm(struct mm_id *mm_idp) if (proc_mm) { err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, mm_idp->u.mm_fd); - if (err) - panic("__switch_mm - PTRACE_SWITCH_MM failed, " - "errno = %d\n", errno); + if (err) { + printk(UM_KERN_ERR "__switch_mm - PTRACE_SWITCH_MM " + "failed, errno = %d\n", errno); + fatal_sigsegv(); + } } else userspace_pid[0] = mm_idp->u.pid; } |