diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/x86/Makefile | 6 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/ptrace_syscall.c | 294 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/raw_syscall_helper_32.S | 46 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/test_syscall_vdso.c | 401 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/thunks_32.S | 55 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/unwind_vdso.c | 211 |
6 files changed, 1011 insertions, 2 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 29089b24d18b..389701f59940 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -4,8 +4,8 @@ include ../lib.mk .PHONY: all all_32 all_64 warn_32bit_failure clean -TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt -TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn +TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt ptrace_syscall +TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn test_syscall_vdso unwind_vdso TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32) @@ -60,3 +60,5 @@ endif # Some tests have additional dependencies. sysret_ss_attrs_64: thunks.S +ptrace_syscall_32: raw_syscall_helper_32.S +test_syscall_vdso_32: thunks_32.S diff --git a/tools/testing/selftests/x86/ptrace_syscall.c b/tools/testing/selftests/x86/ptrace_syscall.c new file mode 100644 index 000000000000..5105b49cd8aa --- /dev/null +++ b/tools/testing/selftests/x86/ptrace_syscall.c @@ -0,0 +1,294 @@ +#define _GNU_SOURCE + +#include <sys/ptrace.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/syscall.h> +#include <sys/user.h> +#include <unistd.h> +#include <errno.h> +#include <stddef.h> +#include <stdio.h> +#include <err.h> +#include <string.h> +#include <asm/ptrace-abi.h> +#include <sys/auxv.h> + +/* Bitness-agnostic defines for user_regs_struct fields. */ +#ifdef __x86_64__ +# define user_syscall_nr orig_rax +# define user_arg0 rdi +# define user_arg1 rsi +# define user_arg2 rdx +# define user_arg3 r10 +# define user_arg4 r8 +# define user_arg5 r9 +# define user_ip rip +# define user_ax rax +#else +# define user_syscall_nr orig_eax +# define user_arg0 ebx +# define user_arg1 ecx +# define user_arg2 edx +# define user_arg3 esi +# define user_arg4 edi +# define user_arg5 ebp +# define user_ip eip +# define user_ax eax +#endif + +static int nerrs = 0; + +struct syscall_args32 { + uint32_t nr, arg0, arg1, arg2, arg3, arg4, arg5; +}; + +#ifdef __i386__ +extern void sys32_helper(struct syscall_args32 *, void *); +extern void int80_and_ret(void); +#endif + +/* + * Helper to invoke int80 with controlled regs and capture the final regs. + */ +static void do_full_int80(struct syscall_args32 *args) +{ +#ifdef __x86_64__ + register unsigned long bp asm("bp") = args->arg5; + asm volatile ("int $0x80" + : "+a" (args->nr), + "+b" (args->arg0), "+c" (args->arg1), "+d" (args->arg2), + "+S" (args->arg3), "+D" (args->arg4), "+r" (bp)); + args->arg5 = bp; +#else + sys32_helper(args, int80_and_ret); +#endif +} + +#ifdef __i386__ +static void (*vsyscall32)(void); + +/* + * Nasty helper to invoke AT_SYSINFO (i.e. __kernel_vsyscall) with + * controlled regs and capture the final regs. This is so nasty that it + * crashes my copy of gdb :) + */ +static void do_full_vsyscall32(struct syscall_args32 *args) +{ + sys32_helper(args, vsyscall32); +} +#endif + +static siginfo_t wait_trap(pid_t chld) +{ + siginfo_t si; + if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0) + err(1, "waitid"); + if (si.si_pid != chld) + errx(1, "got unexpected pid in event\n"); + if (si.si_code != CLD_TRAPPED) + errx(1, "got unexpected event type %d\n", si.si_code); + return si; +} + +static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), + int flags) +{ + struct sigaction sa; + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = handler; + sa.sa_flags = SA_SIGINFO | flags; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +static void clearhandler(int sig) +{ + struct sigaction sa; + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = SIG_DFL; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +#ifdef __x86_64__ +# define REG_BP REG_RBP +#else +# define REG_BP REG_EBP +#endif + +static void empty_handler(int sig, siginfo_t *si, void *ctx_void) +{ +} + +static void test_sys32_regs(void (*do_syscall)(struct syscall_args32 *)) +{ + struct syscall_args32 args = { + .nr = 224, /* gettid */ + .arg0 = 10, .arg1 = 11, .arg2 = 12, + .arg3 = 13, .arg4 = 14, .arg5 = 15, + }; + + do_syscall(&args); + + if (args.nr != getpid() || + args.arg0 != 10 || args.arg1 != 11 || args.arg2 != 12 || + args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) { + printf("[FAIL]\tgetpid() failed to preseve regs\n"); + nerrs++; + } else { + printf("[OK]\tgetpid() preserves regs\n"); + } + + sethandler(SIGUSR1, empty_handler, 0); + + args.nr = 37; /* kill */ + args.arg0 = getpid(); + args.arg1 = SIGUSR1; + do_syscall(&args); + if (args.nr != 0 || + args.arg0 != getpid() || args.arg1 != SIGUSR1 || args.arg2 != 12 || + args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) { + printf("[FAIL]\tkill(getpid(), SIGUSR1) failed to preseve regs\n"); + nerrs++; + } else { + printf("[OK]\tkill(getpid(), SIGUSR1) preserves regs\n"); + } + clearhandler(SIGUSR1); +} + +static void test_ptrace_syscall_restart(void) +{ + printf("[RUN]\tptrace-induced syscall restart\n"); + pid_t chld = fork(); + if (chld < 0) + err(1, "fork"); + + if (chld == 0) { + if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0) + err(1, "PTRACE_TRACEME"); + + printf("\tChild will make one syscall\n"); + raise(SIGSTOP); + + syscall(SYS_gettid, 10, 11, 12, 13, 14, 15); + _exit(0); + } + + int status; + + /* Wait for SIGSTOP. */ + if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status)) + err(1, "waitpid"); + + struct user_regs_struct regs; + + printf("[RUN]\tSYSEMU\n"); + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSCALL"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + if (regs.user_syscall_nr != SYS_gettid || + regs.user_arg0 != 10 || regs.user_arg1 != 11 || + regs.user_arg2 != 12 || regs.user_arg3 != 13 || + regs.user_arg4 != 14 || regs.user_arg5 != 15) { + printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tInitial nr and args are correct\n"); + } + + printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n", + (unsigned long)regs.user_ip); + + /* + * This does exactly what it appears to do if syscall is int80 or + * SYSCALL64. For SYSCALL32 or SYSENTER, though, this is highly + * magical. It needs to work so that ptrace and syscall restart + * work as expected. + */ + regs.user_ax = regs.user_syscall_nr; + regs.user_ip -= 2; + if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_SETREGS"); + + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSCALL"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + if (regs.user_syscall_nr != SYS_gettid || + regs.user_arg0 != 10 || regs.user_arg1 != 11 || + regs.user_arg2 != 12 || regs.user_arg3 != 13 || + regs.user_arg4 != 14 || regs.user_arg5 != 15) { + printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tRestarted nr and args are correct\n"); + } + + printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n", + (unsigned long)regs.user_ip); + + regs.user_ax = SYS_getpid; + regs.user_arg0 = 20; + regs.user_arg1 = 21; + regs.user_arg2 = 22; + regs.user_arg3 = 23; + regs.user_arg4 = 24; + regs.user_arg5 = 25; + regs.user_ip -= 2; + + if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_SETREGS"); + + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSCALL"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + if (regs.user_syscall_nr != SYS_getpid || + regs.user_arg0 != 20 || regs.user_arg1 != 21 || regs.user_arg2 != 22 || + regs.user_arg3 != 23 || regs.user_arg4 != 24 || regs.user_arg5 != 25) { + printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tReplacement nr and args are correct\n"); + } + + if (ptrace(PTRACE_CONT, chld, 0, 0) != 0) + err(1, "PTRACE_CONT"); + if (waitpid(chld, &status, 0) != chld) + err(1, "waitpid"); + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + printf("[FAIL]\tChild failed\n"); + nerrs++; + } else { + printf("[OK]\tChild exited cleanly\n"); + } +} + +int main() +{ + printf("[RUN]\tCheck int80 return regs\n"); + test_sys32_regs(do_full_int80); + +#if defined(__i386__) && (!defined(__GLIBC__) || __GLIBC__ > 2 || __GLIBC_MINOR__ >= 16) + vsyscall32 = (void *)getauxval(AT_SYSINFO); + printf("[RUN]\tCheck AT_SYSINFO return regs\n"); + test_sys32_regs(do_full_vsyscall32); +#endif + + test_ptrace_syscall_restart(); + + return 0; +} diff --git a/tools/testing/selftests/x86/raw_syscall_helper_32.S b/tools/testing/selftests/x86/raw_syscall_helper_32.S new file mode 100644 index 000000000000..534e71e35c6a --- /dev/null +++ b/tools/testing/selftests/x86/raw_syscall_helper_32.S @@ -0,0 +1,46 @@ +.global sys32_helper +sys32_helper: + /* Args: syscall_args_32*, function pointer */ + pushl %ebp + pushl %ebx + pushl %esi + pushl %edi + movl 5*4(%esp), %eax /* pointer to args struct */ + + movl 1*4(%eax), %ebx + movl 2*4(%eax), %ecx + movl 3*4(%eax), %edx + movl 4*4(%eax), %esi + movl 5*4(%eax), %edi + movl 6*4(%eax), %ebp + movl 0*4(%eax), %eax + + call *(6*4)(%esp) /* Do the syscall */ + + /* Now we need to recover without losing any reg values */ + pushl %eax + movl 6*4(%esp), %eax + popl 0*4(%eax) + movl %ebx, 1*4(%eax) + movl %ecx, 2*4(%eax) + movl %edx, 3*4(%eax) + movl %esi, 4*4(%eax) + movl %edi, 5*4(%eax) + movl %ebp, 6*4(%eax) + + popl %edi + popl %esi + popl %ebx + popl %ebp + ret + + .type sys32_helper, @function + .size sys32_helper, .-sys32_helper + +.global int80_and_ret +int80_and_ret: + int $0x80 + ret + + .type int80_and_ret, @function + .size int80_and_ret, .-int80_and_ret diff --git a/tools/testing/selftests/x86/test_syscall_vdso.c b/tools/testing/selftests/x86/test_syscall_vdso.c new file mode 100644 index 000000000000..40370354d4c1 --- /dev/null +++ b/tools/testing/selftests/x86/test_syscall_vdso.c @@ -0,0 +1,401 @@ +/* + * 32-bit syscall ABI conformance test. + * + * Copyright (c) 2015 Denys Vlasenko + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +/* + * Can be built statically: + * gcc -Os -Wall -static -m32 test_syscall_vdso.c thunks_32.S + */ +#undef _GNU_SOURCE +#define _GNU_SOURCE 1 +#undef __USE_GNU +#define __USE_GNU 1 +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/select.h> +#include <sys/time.h> +#include <elf.h> +#include <sys/ptrace.h> +#include <sys/wait.h> + +#if !defined(__i386__) +int main(int argc, char **argv, char **envp) +{ + printf("[SKIP]\tNot a 32-bit x86 userspace\n"); + return 0; +} +#else + +long syscall_addr; +long get_syscall(char **envp) +{ + Elf32_auxv_t *auxv; + while (*envp++ != NULL) + continue; + for (auxv = (void *)envp; auxv->a_type != AT_NULL; auxv++) + if (auxv->a_type == AT_SYSINFO) + return auxv->a_un.a_val; + printf("[WARN]\tAT_SYSINFO not supplied\n"); + return 0; +} + +asm ( + " .pushsection .text\n" + " .global int80\n" + "int80:\n" + " int $0x80\n" + " ret\n" + " .popsection\n" +); +extern char int80; + +struct regs64 { + uint64_t rax, rbx, rcx, rdx; + uint64_t rsi, rdi, rbp, rsp; + uint64_t r8, r9, r10, r11; + uint64_t r12, r13, r14, r15; +}; +struct regs64 regs64; +int kernel_is_64bit; + +asm ( + " .pushsection .text\n" + " .code64\n" + "get_regs64:\n" + " push %rax\n" + " mov $regs64, %eax\n" + " pop 0*8(%rax)\n" + " movq %rbx, 1*8(%rax)\n" + " movq %rcx, 2*8(%rax)\n" + " movq %rdx, 3*8(%rax)\n" + " movq %rsi, 4*8(%rax)\n" + " movq %rdi, 5*8(%rax)\n" + " movq %rbp, 6*8(%rax)\n" + " movq %rsp, 7*8(%rax)\n" + " movq %r8, 8*8(%rax)\n" + " movq %r9, 9*8(%rax)\n" + " movq %r10, 10*8(%rax)\n" + " movq %r11, 11*8(%rax)\n" + " movq %r12, 12*8(%rax)\n" + " movq %r13, 13*8(%rax)\n" + " movq %r14, 14*8(%rax)\n" + " movq %r15, 15*8(%rax)\n" + " ret\n" + "poison_regs64:\n" + " movq $0x7f7f7f7f, %r8\n" + " shl $32, %r8\n" + " orq $0x7f7f7f7f, %r8\n" + " movq %r8, %r9\n" + " movq %r8, %r10\n" + " movq %r8, %r11\n" + " movq %r8, %r12\n" + " movq %r8, %r13\n" + " movq %r8, %r14\n" + " movq %r8, %r15\n" + " ret\n" + " .code32\n" + " .popsection\n" +); +extern void get_regs64(void); +extern void poison_regs64(void); +extern unsigned long call64_from_32(void (*function)(void)); +void print_regs64(void) +{ + if (!kernel_is_64bit) + return; + printf("ax:%016llx bx:%016llx cx:%016llx dx:%016llx\n", regs64.rax, regs64.rbx, regs64.rcx, regs64.rdx); + printf("si:%016llx di:%016llx bp:%016llx sp:%016llx\n", regs64.rsi, regs64.rdi, regs64.rbp, regs64.rsp); + printf(" 8:%016llx 9:%016llx 10:%016llx 11:%016llx\n", regs64.r8 , regs64.r9 , regs64.r10, regs64.r11); + printf("12:%016llx 13:%016llx 14:%016llx 15:%016llx\n", regs64.r12, regs64.r13, regs64.r14, regs64.r15); +} + +int check_regs64(void) +{ + int err = 0; + int num = 8; + uint64_t *r64 = ®s64.r8; + + if (!kernel_is_64bit) + return 0; + + do { + if (*r64 == 0x7f7f7f7f7f7f7f7fULL) + continue; /* register did not change */ + if (syscall_addr != (long)&int80) { + /* + * Non-INT80 syscall entrypoints are allowed to clobber R8+ regs: + * either clear them to 0, or for R11, load EFLAGS. + */ + if (*r64 == 0) + continue; + if (num == 11) { + printf("[NOTE]\tR11 has changed:%016llx - assuming clobbered by SYSRET insn\n", *r64); + continue; + } + } else { + /* INT80 syscall entrypoint can be used by + * 64-bit programs too, unlike SYSCALL/SYSENTER. + * Therefore it must preserve R12+ + * (they are callee-saved registers in 64-bit C ABI). + * + * This was probably historically not intended, + * but R8..11 are clobbered (cleared to 0). + * IOW: they are the only registers which aren't + * preserved across INT80 syscall. + */ + if (*r64 == 0 && num <= 11) + continue; + } + printf("[FAIL]\tR%d has changed:%016llx\n", num, *r64); + err++; + } while (r64++, ++num < 16); + + if (!err) + printf("[OK]\tR8..R15 did not leak kernel data\n"); + return err; +} + +int nfds; +fd_set rfds; +fd_set wfds; +fd_set efds; +struct timespec timeout; +sigset_t sigmask; +struct { + sigset_t *sp; + int sz; +} sigmask_desc; + +void prep_args() +{ + nfds = 42; + FD_ZERO(&rfds); + FD_ZERO(&wfds); + FD_ZERO(&efds); + FD_SET(0, &rfds); + FD_SET(1, &wfds); + FD_SET(2, &efds); + timeout.tv_sec = 0; + timeout.tv_nsec = 123; + sigemptyset(&sigmask); + sigaddset(&sigmask, SIGINT); + sigaddset(&sigmask, SIGUSR2); + sigaddset(&sigmask, SIGRTMAX); + sigmask_desc.sp = &sigmask; + sigmask_desc.sz = 8; /* bytes */ +} + +static void print_flags(const char *name, unsigned long r) +{ + static const char *bitarray[] = { + "\n" ,"c\n" ,/* Carry Flag */ + "0 " ,"1 " ,/* Bit 1 - always on */ + "" ,"p " ,/* Parity Flag */ + "0 " ,"3? " , + "" ,"a " ,/* Auxiliary carry Flag */ + "0 " ,"5? " , + "" ,"z " ,/* Zero Flag */ + "" ,"s " ,/* Sign Flag */ + "" ,"t " ,/* Trap Flag */ + "" ,"i " ,/* Interrupt Flag */ + "" ,"d " ,/* Direction Flag */ + "" ,"o " ,/* Overflow Flag */ + "0 " ,"1 " ,/* I/O Privilege Level (2 bits) */ + "0" ,"1" ,/* I/O Privilege Level (2 bits) */ + "" ,"n " ,/* Nested Task */ + "0 " ,"15? ", + "" ,"r " ,/* Resume Flag */ + "" ,"v " ,/* Virtual Mode */ + "" ,"ac " ,/* Alignment Check/Access Control */ + "" ,"vif ",/* Virtual Interrupt Flag */ + "" ,"vip ",/* Virtual Interrupt Pending */ + "" ,"id " ,/* CPUID detection */ + NULL + }; + const char **bitstr; + int bit; + + printf("%s=%016lx ", name, r); + bitstr = bitarray + 42; + bit = 21; + if ((r >> 22) != 0) + printf("(extra bits are set) "); + do { + if (bitstr[(r >> bit) & 1][0]) + fputs(bitstr[(r >> bit) & 1], stdout); + bitstr -= 2; + bit--; + } while (bit >= 0); +} + +int run_syscall(void) +{ + long flags, bad_arg; + + prep_args(); + + if (kernel_is_64bit) + call64_from_32(poison_regs64); + /*print_regs64();*/ + + asm("\n" + /* Try 6-arg syscall: pselect. It should return quickly */ + " push %%ebp\n" + " mov $308, %%eax\n" /* PSELECT */ + " mov nfds, %%ebx\n" /* ebx arg1 */ + " mov $rfds, %%ecx\n" /* ecx arg2 */ + " mov $wfds, %%edx\n" /* edx arg3 */ + " mov $efds, %%esi\n" /* esi arg4 */ + " mov $timeout, %%edi\n" /* edi arg5 */ + " mov $sigmask_desc, %%ebp\n" /* %ebp arg6 */ + " push $0x200ed7\n" /* set almost all flags */ + " popf\n" /* except TF, IOPL, NT, RF, VM, AC, VIF, VIP */ + " call *syscall_addr\n" + /* Check that registers are not clobbered */ + " pushf\n" + " pop %%eax\n" + " cld\n" + " cmp nfds, %%ebx\n" /* ebx arg1 */ + " mov $1, %%ebx\n" + " jne 1f\n" + " cmp $rfds, %%ecx\n" /* ecx arg2 */ + " mov $2, %%ebx\n" + " jne 1f\n" + " cmp $wfds, %%edx\n" /* edx arg3 */ + " mov $3, %%ebx\n" + " jne 1f\n" + " cmp $efds, %%esi\n" /* esi arg4 */ + " mov $4, %%ebx\n" + " jne 1f\n" + " cmp $timeout, %%edi\n" /* edi arg5 */ + " mov $5, %%ebx\n" + " jne 1f\n" + " cmpl $sigmask_desc, %%ebp\n" /* %ebp arg6 */ + " mov $6, %%ebx\n" + " jne 1f\n" + " mov $0, %%ebx\n" + "1:\n" + " pop %%ebp\n" + : "=a" (flags), "=b" (bad_arg) + : + : "cx", "dx", "si", "di" + ); + + if (kernel_is_64bit) { + memset(®s64, 0x77, sizeof(regs64)); + call64_from_32(get_regs64); + /*print_regs64();*/ + } + + /* + * On paravirt kernels, flags are not preserved across syscalls. + * Thus, we do not consider it a bug if some are changed. + * We just show ones which do. + */ + if ((0x200ed7 ^ flags) != 0) { + print_flags("[WARN]\tFlags before", 0x200ed7); + print_flags("[WARN]\tFlags after", flags); + print_flags("[WARN]\tFlags change", (0x200ed7 ^ flags)); + } + + if (bad_arg) { + printf("[FAIL]\targ#%ld clobbered\n", bad_arg); + return 1; + } + printf("[OK]\tArguments are preserved across syscall\n"); + + return check_regs64(); +} + +int run_syscall_twice() +{ + int exitcode = 0; + long sv; + + if (syscall_addr) { + printf("[RUN]\tExecuting 6-argument 32-bit syscall via VDSO\n"); + exitcode = run_syscall(); + } + sv = syscall_addr; + syscall_addr = (long)&int80; + printf("[RUN]\tExecuting 6-argument 32-bit syscall via INT 80\n"); + exitcode += run_syscall(); + syscall_addr = sv; + return exitcode; +} + +void ptrace_me() +{ + pid_t pid; + + fflush(NULL); + pid = fork(); + if (pid < 0) + exit(1); + if (pid == 0) { + /* child */ + if (ptrace(PTRACE_TRACEME, 0L, 0L, 0L) != 0) + exit(0); + raise(SIGSTOP); + return; + } + /* parent */ + printf("[RUN]\tRunning tests under ptrace\n"); + while (1) { + int status; + pid = waitpid(-1, &status, __WALL); + if (WIFEXITED(status)) + exit(WEXITSTATUS(status)); + if (WIFSIGNALED(status)) + exit(WTERMSIG(status)); + if (pid <= 0 || !WIFSTOPPED(status)) /* paranoia */ + exit(255); + /* + * Note: we do not inject sig = WSTOPSIG(status). + * We probably should, but careful: do not inject SIGTRAP + * generated by syscall entry/exit stops. + * That kills the child. + */ + ptrace(PTRACE_SYSCALL, pid, 0L, 0L /*sig*/); + } +} + +int main(int argc, char **argv, char **envp) +{ + int exitcode = 0; + int cs; + + asm("\n" + " movl %%cs, %%eax\n" + : "=a" (cs) + ); + kernel_is_64bit = (cs == 0x23); + if (!kernel_is_64bit) + printf("[NOTE]\tNot a 64-bit kernel, won't test R8..R15 leaks\n"); + + /* This only works for non-static builds: + * syscall_addr = dlsym(dlopen("linux-gate.so.1", RTLD_NOW), "__kernel_vsyscall"); + */ + syscall_addr = get_syscall(envp); + + exitcode += run_syscall_twice(); + ptrace_me(); + exitcode += run_syscall_twice(); + + return exitcode; +} +#endif diff --git a/tools/testing/selftests/x86/thunks_32.S b/tools/testing/selftests/x86/thunks_32.S new file mode 100644 index 000000000000..29b644bb9f2f --- /dev/null +++ b/tools/testing/selftests/x86/thunks_32.S @@ -0,0 +1,55 @@ +/* + * thunks_32.S - assembly helpers for mixed-bitness code + * Copyright (c) 2015 Denys Vlasenko + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * These are little helpers that make it easier to switch bitness on + * the fly. + */ + + .text + .code32 + + .global call64_from_32 + .type call32_from_64, @function + + // 4(%esp): function to call +call64_from_32: + // Fetch function address + mov 4(%esp), %eax + + // Save registers which are callee-clobbered by 64-bit ABI + push %ecx + push %edx + push %esi + push %edi + + // Switch to long mode + jmp $0x33,$1f +1: .code64 + + // Call the function + call *%rax + + // Switch to compatibility mode + push $0x23 /* USER32_CS */ + .code32; push $1f; .code64 /* hack: can't have X86_64_32S relocation in 32-bit ELF */ + lretq +1: .code32 + + pop %edi + pop %esi + pop %edx + pop %ecx + + ret + +.size call64_from_32, .-call64_from_32 diff --git a/tools/testing/selftests/x86/unwind_vdso.c b/tools/testing/selftests/x86/unwind_vdso.c new file mode 100644 index 000000000000..00a26a82fa98 --- /dev/null +++ b/tools/testing/selftests/x86/unwind_vdso.c @@ -0,0 +1,211 @@ +/* + * unwind_vdso.c - tests unwind info for AT_SYSINFO in the vDSO + * Copyright (c) 2014-2015 Andrew Lutomirski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * This tests __kernel_vsyscall's unwind info. + */ + +#define _GNU_SOURCE + +#include <features.h> +#include <stdio.h> + +#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16 + +int main() +{ + /* We need getauxval(). */ + printf("[SKIP]\tGLIBC before 2.16 cannot compile this test\n"); + return 0; +} + +#else + +#include <sys/time.h> +#include <stdlib.h> +#include <syscall.h> +#include <unistd.h> +#include <string.h> +#include <inttypes.h> +#include <sys/mman.h> +#include <signal.h> +#include <sys/ucontext.h> +#include <err.h> +#include <stddef.h> +#include <stdbool.h> +#include <sys/ptrace.h> +#include <sys/user.h> +#include <sys/ucontext.h> +#include <link.h> +#include <sys/auxv.h> +#include <dlfcn.h> +#include <unwind.h> + +static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), + int flags) +{ + struct sigaction sa; + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = handler; + sa.sa_flags = SA_SIGINFO | flags; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +#ifdef __x86_64__ +# define WIDTH "q" +#else +# define WIDTH "l" +#endif + +static unsigned long get_eflags(void) +{ + unsigned long eflags; + asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags)); + return eflags; +} + +static void set_eflags(unsigned long eflags) +{ + asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH + : : "rm" (eflags) : "flags"); +} + +#define X86_EFLAGS_TF (1UL << 8) + +static volatile sig_atomic_t nerrs; +static unsigned long sysinfo; +static bool got_sysinfo = false; +static unsigned long return_address; + +struct unwind_state { + unsigned long ip; /* trap source */ + int depth; /* -1 until we hit the trap source */ +}; + +_Unwind_Reason_Code trace_fn(struct _Unwind_Context * ctx, void *opaque) +{ + struct unwind_state *state = opaque; + unsigned long ip = _Unwind_GetIP(ctx); + + if (state->depth == -1) { + if (ip == state->ip) + state->depth = 0; + else + return _URC_NO_REASON; /* Not there yet */ + } + printf("\t 0x%lx\n", ip); + + if (ip == return_address) { + /* Here we are. */ + unsigned long eax = _Unwind_GetGR(ctx, 0); + unsigned long ecx = _Unwind_GetGR(ctx, 1); + unsigned long edx = _Unwind_GetGR(ctx, 2); + unsigned long ebx = _Unwind_GetGR(ctx, 3); + unsigned long ebp = _Unwind_GetGR(ctx, 5); + unsigned long esi = _Unwind_GetGR(ctx, 6); + unsigned long edi = _Unwind_GetGR(ctx, 7); + bool ok = (eax == SYS_getpid || eax == getpid()) && + ebx == 1 && ecx == 2 && edx == 3 && + esi == 4 && edi == 5 && ebp == 6; + + if (!ok) + nerrs++; + printf("[%s]\t NR = %ld, args = %ld, %ld, %ld, %ld, %ld, %ld\n", + (ok ? "OK" : "FAIL"), + eax, ebx, ecx, edx, esi, edi, ebp); + + return _URC_NORMAL_STOP; + } else { + state->depth++; + return _URC_NO_REASON; + } +} + +static void sigtrap(int sig, siginfo_t *info, void *ctx_void) +{ + ucontext_t *ctx = (ucontext_t *)ctx_void; + struct unwind_state state; + unsigned long ip = ctx->uc_mcontext.gregs[REG_EIP]; + + if (!got_sysinfo && ip == sysinfo) { + got_sysinfo = true; + + /* Find the return address. */ + return_address = *(unsigned long *)(unsigned long)ctx->uc_mcontext.gregs[REG_ESP]; + + printf("\tIn vsyscall at 0x%lx, returning to 0x%lx\n", + ip, return_address); + } + + if (!got_sysinfo) + return; /* Not there yet */ + + if (ip == return_address) { + ctx->uc_mcontext.gregs[REG_EFL] &= ~X86_EFLAGS_TF; + printf("\tVsyscall is done\n"); + return; + } + + printf("\tSIGTRAP at 0x%lx\n", ip); + + state.ip = ip; + state.depth = -1; + _Unwind_Backtrace(trace_fn, &state); +} + +int main() +{ + sysinfo = getauxval(AT_SYSINFO); + printf("\tAT_SYSINFO is 0x%lx\n", sysinfo); + + Dl_info info; + if (!dladdr((void *)sysinfo, &info)) { + printf("[WARN]\tdladdr failed on AT_SYSINFO\n"); + } else { + printf("[OK]\tAT_SYSINFO maps to %s, loaded at 0x%p\n", + info.dli_fname, info.dli_fbase); + } + + sethandler(SIGTRAP, sigtrap, 0); + + syscall(SYS_getpid); /* Force symbol binding without TF set. */ + printf("[RUN]\tSet TF and check a fast syscall\n"); + set_eflags(get_eflags() | X86_EFLAGS_TF); + syscall(SYS_getpid, 1, 2, 3, 4, 5, 6); + if (!got_sysinfo) { + set_eflags(get_eflags() & ~X86_EFLAGS_TF); + + /* + * The most likely cause of this is that you're on Debian or + * a Debian-based distro, you're missing libc6-i686, and you're + * affected by libc/19006 (https://sourceware.org/PR19006). + */ + printf("[WARN]\tsyscall(2) didn't enter AT_SYSINFO\n"); + } + + if (get_eflags() & X86_EFLAGS_TF) { + printf("[FAIL]\tTF is still set\n"); + nerrs++; + } + + if (nerrs) { + printf("[FAIL]\tThere were errors\n"); + return 1; + } else { + printf("[OK]\tAll is well\n"); + return 0; + } +} + +#endif /* New enough libc */ |