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_relaxed(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_relaxed(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;
}
/**
* seccomp_send_sigsys - signals the task to allow in-process syscall emulation
* @syscall: syscall number to send to userland
* @reason: filter-supplied reason code to send to userland (via si_errno)
*
* Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
*/
static void seccomp_send_sigsys(int syscall, int reason)
{
struct siginfo info;
memset(&info, 0, sizeof(info));
info.si_signo = SIGSYS;
info.si_code = SYS_SECCOMP;
info.si_call_addr = (void __user *)KSTK_EIP(current);
info.si_errno = reason;
info.si_arch = syscall_get_arch(current, task_pt_regs(current));
info.si_syscall = syscall;
force_sig_info(SIGSYS, &info, current);
}
asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, regs->syscallno);
audit_syscall_entry(syscall_get_arch(), regs->syscallno,
regs->orig_x0, regs->regs[1], regs->regs[2], regs->regs[3]);
return regs->syscallno;
}
/*
* Endianness is explicitly ignored and left for BPF program authors to manage
* as per the specific architecture.
*/
static void populate_seccomp_data(struct seccomp_data *sd)
{
struct task_struct *task = current;
struct pt_regs *regs = task_pt_regs(task);
unsigned long args[6];
sd->nr = syscall_get_nr(task, regs);
sd->arch = syscall_get_arch();
syscall_get_arguments(task, regs, 0, 6, args);
sd->args[0] = args[0];
sd->args[1] = args[1];
sd->args[2] = args[2];
sd->args[3] = args[3];
sd->args[4] = args[4];
sd->args[5] = args[5];
sd->instruction_pointer = KSTK_EIP(task);
}
/*
* Notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
{
user_exit();
current_thread_info()->syscall = syscall;
if (test_thread_flag(TIF_SYSCALL_TRACE)) {
if (tracehook_report_syscall_entry(regs))
return -1;
syscall = current_thread_info()->syscall;
}
#ifdef CONFIG_SECCOMP
if (unlikely(test_thread_flag(TIF_SECCOMP))) {
int ret, i;
struct seccomp_data sd;
unsigned long args[6];
sd.nr = syscall;
sd.arch = syscall_get_arch();
syscall_get_arguments(current, regs, 0, 6, args);
for (i = 0; i < 6; i++)
sd.args[i] = args[i];
sd.instruction_pointer = KSTK_EIP(current);
ret = __secure_computing(&sd);
if (ret == -1)
return ret;
syscall = current_thread_info()->syscall;
}
#endif
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->regs[2]);
audit_syscall_entry(syscall, regs->regs[4], regs->regs[5],
regs->regs[6], regs->regs[7]);
/*
* Negative syscall numbers are mistaken for rejected syscalls, but
* won't have had the return value set appropriately, so we do so now.
*/
if (syscall < 0)
syscall_set_return_value(current, regs, -ENOSYS, 0);
return syscall;
}
asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
/* Do the secure computing check first; failures should be fast. */
if (secure_computing() == -1)
return -1;
if (test_thread_flag_relaxed(TIF_SYSCALL_TRACE))
tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
if (test_thread_flag_relaxed(TIF_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, regs->syscallno);
audit_syscall_entry(syscall_get_arch(), regs->syscallno,
regs->orig_x0, regs->regs[1], regs->regs[2], regs->regs[3]);
return regs->syscallno;
}
/*
* Endianness is explicitly ignored and left for BPF program authors to manage
* as per the specific architecture.
*/
static void populate_seccomp_data(struct seccomp_data *sd)
{
struct task_struct *task = current;
struct pt_regs *regs = task_pt_regs(task);
sd->nr = syscall_get_nr(task, regs);
sd->arch = syscall_get_arch(task, regs);
/* Unroll syscall_get_args to help gcc on arm. */
syscall_get_arguments(task, regs, 0, 1, (unsigned long *) &sd->args[0]);
syscall_get_arguments(task, regs, 1, 1, (unsigned long *) &sd->args[1]);
syscall_get_arguments(task, regs, 2, 1, (unsigned long *) &sd->args[2]);
syscall_get_arguments(task, regs, 3, 1, (unsigned long *) &sd->args[3]);
syscall_get_arguments(task, regs, 4, 1, (unsigned long *) &sd->args[4]);
syscall_get_arguments(task, regs, 5, 1, (unsigned long *) &sd->args[5]);
sd->instruction_pointer = KSTK_EIP(task);
}
/**
* bpf_load: checks and returns a pointer to the requested offset
* @off: offset into struct seccomp_data to load from
*
* Returns the requested 32-bits of data.
* seccomp_chk_filter() should assure that @off is 32-bit aligned
* and not out of bounds. Failure to do so is a BUG.
*/
u32 seccomp_bpf_load(int off)
{
struct pt_regs *regs = task_pt_regs(current);
if (off == BPF_DATA(nr))
return syscall_get_nr(current, regs);
if (off == BPF_DATA(arch))
return syscall_get_arch(current, regs);
if (off >= BPF_DATA(args[0]) && off < BPF_DATA(args[6])) {
unsigned long value;
int arg = (off - BPF_DATA(args[0])) / sizeof(u64);
int index = !!(off % sizeof(u64));
syscall_get_arguments(current, regs, arg, 1, &value);
return get_u32(value, index);
}
if (off == BPF_DATA(instruction_pointer))
return get_u32(KSTK_EIP(current), 0);
if (off == BPF_DATA(instruction_pointer) + sizeof(u32))
return get_u32(KSTK_EIP(current), 1);
/* seccomp_chk_filter should make this impossible. */
BUG();
}
/*
* Notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
{
long ret = 0;
user_exit();
if (secure_computing(syscall) == -1)
return -1;
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs))
ret = -1;
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->regs[2]);
audit_syscall_entry(syscall_get_arch(),
syscall,
regs->regs[4], regs->regs[5],
regs->regs[6], regs->regs[7]);
return syscall;
}
