4ea6a9a28f
Thread credentials are maintained as follows: each thread has a pointer to creds and a reference on them. The pointer is compared with proc's creds on userspace<->kernel boundary and updated if needed. This patch introduces a counter which can be compared instead, so that more structures can use this scheme without adding more comparisons on the boundary.
246 lines
7.1 KiB
C
246 lines
7.1 KiB
C
/*-
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* Copyright (C) 1994, David Greenman
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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* Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
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*
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* This code is derived from software contributed to Berkeley by
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* the University of Utah, and William Jolitz.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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*/
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#include "opt_capsicum.h"
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#include "opt_ktrace.h"
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__FBSDID("$FreeBSD$");
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#include <sys/capsicum.h>
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#include <sys/ktr.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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#include <security/audit/audit.h>
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static inline int
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syscallenter(struct thread *td, struct syscall_args *sa)
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{
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struct proc *p;
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int error, traced;
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PCPU_INC(cnt.v_syscall);
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p = td->td_proc;
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td->td_pticks = 0;
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if (td->td_cowgen != p->p_cowgen)
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thread_cow_update(td);
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if (p->p_flag & P_TRACED) {
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traced = 1;
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PROC_LOCK(p);
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td->td_dbgflags &= ~TDB_USERWR;
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td->td_dbgflags |= TDB_SCE;
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PROC_UNLOCK(p);
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} else
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traced = 0;
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error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSCALL))
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ktrsyscall(sa->code, sa->narg, sa->args);
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#endif
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KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
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(uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
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"arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
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if (error == 0) {
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STOPEVENT(p, S_SCE, sa->narg);
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if (p->p_flag & P_TRACED && p->p_stops & S_PT_SCE) {
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PROC_LOCK(p);
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ptracestop((td), SIGTRAP);
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PROC_UNLOCK(p);
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}
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if (td->td_dbgflags & TDB_USERWR) {
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/*
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* Reread syscall number and arguments if
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* debugger modified registers or memory.
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*/
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error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSCALL))
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ktrsyscall(sa->code, sa->narg, sa->args);
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#endif
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if (error != 0)
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goto retval;
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}
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#ifdef CAPABILITY_MODE
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/*
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* In capability mode, we only allow access to system calls
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* flagged with SYF_CAPENABLED.
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*/
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if (IN_CAPABILITY_MODE(td) &&
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!(sa->callp->sy_flags & SYF_CAPENABLED)) {
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error = ECAPMODE;
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goto retval;
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}
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#endif
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error = syscall_thread_enter(td, sa->callp);
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if (error != 0)
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goto retval;
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#ifdef KDTRACE_HOOKS
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/*
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* If the systrace module has registered it's probe
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* callback and if there is a probe active for the
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* syscall 'entry', process the probe.
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*/
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if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
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(*systrace_probe_func)(sa->callp->sy_entry, sa->code,
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sa->callp, sa->args, 0);
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#endif
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AUDIT_SYSCALL_ENTER(sa->code, td);
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error = (sa->callp->sy_call)(td, sa->args);
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AUDIT_SYSCALL_EXIT(error, td);
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/* Save the latest error return value. */
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if ((td->td_pflags & TDP_NERRNO) == 0)
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td->td_errno = error;
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#ifdef KDTRACE_HOOKS
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/*
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* If the systrace module has registered it's probe
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* callback and if there is a probe active for the
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* syscall 'return', process the probe.
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*/
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if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
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(*systrace_probe_func)(sa->callp->sy_return, sa->code,
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sa->callp, NULL, (error) ? -1 : td->td_retval[0]);
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#endif
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syscall_thread_exit(td, sa->callp);
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}
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retval:
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KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
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(uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
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"retval0:%#lx", td->td_retval[0], "retval1:%#lx",
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td->td_retval[1]);
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if (traced) {
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PROC_LOCK(p);
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td->td_dbgflags &= ~TDB_SCE;
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PROC_UNLOCK(p);
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}
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(p->p_sysent->sv_set_syscall_retval)(td, error);
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return (error);
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}
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static inline void
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syscallret(struct thread *td, int error, struct syscall_args *sa __unused)
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{
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struct proc *p, *p2;
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int traced;
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p = td->td_proc;
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/*
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* Handle reschedule and other end-of-syscall issues
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*/
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userret(td, td->td_frame);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSRET)) {
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ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
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error : td->td_errno, td->td_retval[0]);
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}
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#endif
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td->td_pflags &= ~TDP_NERRNO;
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if (p->p_flag & P_TRACED) {
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traced = 1;
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PROC_LOCK(p);
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td->td_dbgflags |= TDB_SCX;
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PROC_UNLOCK(p);
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} else
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traced = 0;
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/*
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* This works because errno is findable through the
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* register set. If we ever support an emulation where this
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* is not the case, this code will need to be revisited.
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*/
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STOPEVENT(p, S_SCX, sa->code);
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if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
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PROC_LOCK(p);
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/*
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* If tracing the execed process, trap to the debugger
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* so that breakpoints can be set before the program
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* executes. If debugger requested tracing of syscall
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* returns, do it now too.
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*/
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if (traced &&
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((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
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(p->p_stops & S_PT_SCX) != 0))
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ptracestop(td, SIGTRAP);
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td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
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PROC_UNLOCK(p);
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}
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if (td->td_pflags & TDP_RFPPWAIT) {
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/*
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* Preserve synchronization semantics of vfork. If
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* waiting for child to exec or exit, fork set
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* P_PPWAIT on child, and there we sleep on our proc
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* (in case of exit).
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*
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* Do it after the ptracestop() above is finished, to
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* not block our debugger until child execs or exits
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* to finish vfork wait.
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*/
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td->td_pflags &= ~TDP_RFPPWAIT;
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p2 = td->td_rfppwait_p;
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again:
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PROC_LOCK(p2);
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while (p2->p_flag & P_PPWAIT) {
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PROC_LOCK(p);
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if (thread_suspend_check_needed()) {
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PROC_UNLOCK(p2);
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thread_suspend_check(0);
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PROC_UNLOCK(p);
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goto again;
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} else {
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PROC_UNLOCK(p);
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}
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cv_timedwait(&p2->p_pwait, &p2->p_mtx, hz);
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}
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PROC_UNLOCK(p2);
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}
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}
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