diff options
Diffstat (limited to 'arch/arm64/kernel/ptrace.c')
| -rw-r--r-- | arch/arm64/kernel/ptrace.c | 150 |
1 files changed, 72 insertions, 78 deletions
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index aebfc1519e8e..f47e70fed6af 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -19,12 +19,15 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/audit.h> +#include <linux/compat.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/ptrace.h> #include <linux/user.h> +#include <linux/seccomp.h> #include <linux/security.h> #include <linux/init.h> #include <linux/signal.h> @@ -38,6 +41,7 @@ #include <asm/compat.h> #include <asm/debug-monitors.h> #include <asm/pgtable.h> +#include <asm/syscall.h> #include <asm/traps.h> #include <asm/system_misc.h> @@ -53,28 +57,6 @@ void ptrace_disable(struct task_struct *child) { } -/* - * Handle hitting a breakpoint. - */ -static int ptrace_break(struct pt_regs *regs) -{ - siginfo_t info = { - .si_signo = SIGTRAP, - .si_errno = 0, - .si_code = TRAP_BRKPT, - .si_addr = (void __user *)instruction_pointer(regs), - }; - - force_sig_info(SIGTRAP, &info, current); - return 0; -} - -static int arm64_break_trap(unsigned long addr, unsigned int esr, - struct pt_regs *regs) -{ - return ptrace_break(regs); -} - #ifdef CONFIG_HAVE_HW_BREAKPOINT /* * Handle hitting a HW-breakpoint. @@ -819,33 +801,6 @@ static const struct user_regset_view user_aarch32_view = { .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets) }; -int aarch32_break_trap(struct pt_regs *regs) -{ - unsigned int instr; - bool bp = false; - void __user *pc = (void __user *)instruction_pointer(regs); - - if (compat_thumb_mode(regs)) { - /* get 16-bit Thumb instruction */ - get_user(instr, (u16 __user *)pc); - if (instr == AARCH32_BREAK_THUMB2_LO) { - /* get second half of 32-bit Thumb-2 instruction */ - get_user(instr, (u16 __user *)(pc + 2)); - bp = instr == AARCH32_BREAK_THUMB2_HI; - } else { - bp = instr == AARCH32_BREAK_THUMB; - } - } else { - /* 32-bit ARM instruction */ - get_user(instr, (u32 __user *)pc); - bp = (instr & ~0xf0000000) == AARCH32_BREAK_ARM; - } - - if (bp) - return ptrace_break(regs); - return 1; -} - static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off, compat_ulong_t __user *ret) { @@ -1110,48 +1065,87 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) { - return ptrace_request(child, request, addr, data); -} + int ret; + switch (request) { + case PTRACE_SET_SYSCALL: + task_pt_regs(child)->syscallno = data; + ret = 0; + break; + default: + ret = ptrace_request(child, request, addr, data); + break; + } -static int __init ptrace_break_init(void) -{ - hook_debug_fault_code(DBG_ESR_EVT_BRK, arm64_break_trap, SIGTRAP, - TRAP_BRKPT, "ptrace BRK handler"); - return 0; + return ret; } -core_initcall(ptrace_break_init); +enum ptrace_syscall_dir { + PTRACE_SYSCALL_ENTER = 0, + PTRACE_SYSCALL_EXIT, +}; -asmlinkage int syscall_trace(int dir, struct pt_regs *regs) +static void tracehook_report_syscall(struct pt_regs *regs, + enum ptrace_syscall_dir dir) { + int regno; unsigned long saved_reg; - if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return regs->syscallno; - - if (is_compat_task()) { - /* AArch32 uses ip (r12) for scratch */ - saved_reg = regs->regs[12]; - regs->regs[12] = dir; - } else { - /* - * Save X7. X7 is used to denote syscall entry/exit: - * X7 = 0 -> entry, = 1 -> exit - */ - saved_reg = regs->regs[7]; - regs->regs[7] = dir; - } + /* + * A scratch register (ip(r12) on AArch32, x7 on AArch64) is + * used to denote syscall entry/exit: + */ + regno = (is_compat_task() ? 12 : 7); + saved_reg = regs->regs[regno]; + regs->regs[regno] = dir; - if (dir) + if (dir == PTRACE_SYSCALL_EXIT) tracehook_report_syscall_exit(regs, 0); else if (tracehook_report_syscall_entry(regs)) regs->syscallno = ~0UL; - if (is_compat_task()) - regs->regs[12] = saved_reg; - else - regs->regs[7] = saved_reg; + regs->regs[regno] = saved_reg; +} + +asmlinkage int syscall_trace_enter(struct pt_regs *regs) +{ + unsigned int saved_syscallno = regs->syscallno; + + /* Do the secure computing check first; failures should be fast. */ + if (secure_computing(regs->syscallno) == -1) + return RET_SKIP_SYSCALL_TRACE; + + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); + + if (IS_SKIP_SYSCALL(regs->syscallno)) { + /* + * RESTRICTION: we can't modify a return value of user + * issued syscall(-1) here. In order to ease this flavor, + * we need to treat whatever value in x0 as a return value, + * but this might result in a bogus value being returned. + */ + /* + * NOTE: syscallno may also be set to -1 if fatal signal is + * detected in tracehook_report_syscall_entry(), but since + * a value set to x0 here is not used in this case, we may + * neglect the case. + */ + if (!test_thread_flag(TIF_SYSCALL_TRACE) || + (IS_SKIP_SYSCALL(saved_syscallno))) + regs->regs[0] = -ENOSYS; + } + + audit_syscall_entry(syscall_get_arch(), regs->syscallno, + regs->orig_x0, regs->regs[1], regs->regs[2], regs->regs[3]); return regs->syscallno; } + +asmlinkage void syscall_trace_exit(struct pt_regs *regs) +{ + audit_syscall_exit(regs); + + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT); +} |