/* $NetBSD: kern_systrace.c,v 1.28 2003/06/03 05:24:01 provos Exp $ */ /* * Copyright 2002, 2003 Niels Provos * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Niels Provos. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __KERNEL_RCSID(0, "$NetBSD: kern_systrace.c,v 1.28 2003/06/03 05:24:01 provos Exp $"); #include "opt_systrace.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __NetBSD__ #define SYSTRACE_LOCK(fst, p) lockmgr(&fst->lock, LK_EXCLUSIVE, NULL) #define SYSTRACE_UNLOCK(fst, p) lockmgr(&fst->lock, LK_RELEASE, NULL) #else #define SYSTRACE_LOCK(fst, p) lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p) #define SYSTRACE_UNLOCK(fst, p) lockmgr(&fst->lock, LK_RELEASE, NULL, p) #endif #ifndef M_XDATA #define M_XDATA M_FILE /* XXX */ #endif #ifdef __NetBSD__ dev_type_open(systraceopen); #else cdev_decl(systrace); #endif #ifdef __NetBSD__ int systracef_read(struct file *, off_t *, struct uio *, struct ucred *, int); int systracef_write(struct file *, off_t *, struct uio *, struct ucred *, int); int systracef_fcntl(struct file *, u_int, void *, struct proc *); int systracef_poll(struct file *, int, struct proc *); #else int systracef_read(struct file *, off_t *, struct uio *, struct ucred *); int systracef_write(struct file *, off_t *, struct uio *, struct ucred *); int systracef_select(struct file *, int, struct proc *); #endif int systracef_kqfilter(struct file *, struct knote *); int systracef_ioctl(struct file *, u_long, void *, struct proc *); int systracef_stat(struct file *, struct stat *, struct proc *); int systracef_close(struct file *, struct proc *); struct str_policy { TAILQ_ENTRY(str_policy) next; int nr; const struct emul *emul; /* Is only valid for this emulation */ int refcount; int nsysent; u_char *sysent; }; #define STR_PROC_ONQUEUE 0x01 #define STR_PROC_WAITANSWER 0x02 #define STR_PROC_SYSCALLRES 0x04 #define STR_PROC_REPORT 0x08 /* Report emulation */ #define STR_PROC_NEEDSEQNR 0x10 /* Answer must quote seqnr */ #define STR_PROC_SETEUID 0x20 /* Elevate privileges */ #define STR_PROC_SETEGID 0x40 struct str_process { TAILQ_ENTRY(str_process) next; struct proc *proc; const struct emul *oldemul; uid_t olduid; gid_t oldgid; pid_t pid; struct fsystrace *parent; struct str_policy *policy; struct systrace_replace *replace; int flags; short answer; short error; u_int16_t seqnr; /* expected reply sequence number */ uid_t seteuid; uid_t saveuid; gid_t setegid; gid_t savegid; }; uid_t systrace_seteuid(struct proc *, uid_t); gid_t systrace_setegid(struct proc *, gid_t); void systrace_lock(void); void systrace_unlock(void); /* Needs to be called with fst locked */ int systrace_attach(struct fsystrace *, pid_t); int systrace_detach(struct str_process *); int systrace_answer(struct str_process *, struct systrace_answer *); int systrace_io(struct str_process *, struct systrace_io *); int systrace_policy(struct fsystrace *, struct systrace_policy *); int systrace_preprepl(struct str_process *, struct systrace_replace *); int systrace_replace(struct str_process *, size_t, register_t []); int systrace_getcwd(struct fsystrace *, struct str_process *); int systrace_processready(struct str_process *); struct proc *systrace_find(struct str_process *); struct str_process *systrace_findpid(struct fsystrace *fst, pid_t pid); void systrace_wakeup(struct fsystrace *); void systrace_closepolicy(struct fsystrace *, struct str_policy *); int systrace_insert_process(struct fsystrace *, struct proc *, struct str_process **); struct str_policy *systrace_newpolicy(struct fsystrace *, int); int systrace_msg_child(struct fsystrace *, struct str_process *, pid_t); int systrace_msg_policyfree(struct fsystrace *, struct str_policy *); int systrace_msg_ask(struct fsystrace *, struct str_process *, int, size_t, register_t []); int systrace_msg_result(struct fsystrace *, struct str_process *, int, int, size_t, register_t [], register_t []); int systrace_msg_emul(struct fsystrace *, struct str_process *); int systrace_msg_ugid(struct fsystrace *, struct str_process *); int systrace_make_msg(struct str_process *, int, struct str_message *); static struct fileops systracefops = { systracef_read, systracef_write, systracef_ioctl, #ifdef __NetBSD__ systracef_fcntl, systracef_poll, #else systracef_select, systracef_kqfilter, #endif systracef_stat, systracef_close #ifdef __NetBSD__ , systracef_kqfilter #endif }; struct pool systr_proc_pl; struct pool systr_policy_pl; struct pool systr_msgcontainer_pl; int systrace_debug = 0; struct lock systrace_lck; #ifdef __NetBSD__ const struct cdevsw systrace_cdevsw = { systraceopen, noclose, noread, nowrite, noioctl, nostop, notty, nopoll, nommap, nokqfilter, }; #endif #define DPRINTF(y) if (systrace_debug) printf y; /* ARGSUSED */ int systracef_read(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred #ifdef __NetBSD__ , int flags #endif ) { struct fsystrace *fst = (struct fsystrace *)fp->f_data; struct str_msgcontainer *cont; int error = 0; if (uio->uio_resid != sizeof(struct str_message)) return (EINVAL); again: systrace_lock(); SYSTRACE_LOCK(fst, curlwp); systrace_unlock(); if ((cont = TAILQ_FIRST(&fst->messages)) != NULL) { error = uiomove((caddr_t)&cont->msg, sizeof(struct str_message), uio); if (!error) { TAILQ_REMOVE(&fst->messages, cont, next); if (!SYSTR_MSG_NOPROCESS(cont)) CLR(cont->strp->flags, STR_PROC_ONQUEUE); pool_put(&systr_msgcontainer_pl, cont); } } else if (TAILQ_FIRST(&fst->processes) == NULL) { /* EOF situation */ ; } else { if (fp->f_flag & FNONBLOCK) error = EAGAIN; else { SYSTRACE_UNLOCK(fst, curlwp); error = tsleep(fst, PWAIT|PCATCH, "systrrd", 0); if (error) goto out; goto again; } } SYSTRACE_UNLOCK(fst, curlwp); out: return (error); } /* ARGSUSED */ int systracef_write(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred #ifdef __NetBSD__ , int flags #endif ) { return (EIO); } #define POLICY_VALID(x) ((x) == SYSTR_POLICY_PERMIT || \ (x) == SYSTR_POLICY_ASK || \ (x) == SYSTR_POLICY_NEVER) /* ARGSUSED */ int systracef_ioctl(struct file *fp, u_long cmd, void *data, struct proc *p) { int ret = 0; struct fsystrace *fst = (struct fsystrace *)fp->f_data; #ifdef __NetBSD__ struct cwdinfo *cwdp; #else struct filedesc *fdp; #endif struct str_process *strp = NULL; pid_t pid = 0; switch (cmd) { case FIONBIO: case FIOASYNC: return (0); case STRIOCDETACH: case STRIOCREPORT: pid = *(pid_t *)data; if (!pid) ret = EINVAL; break; case STRIOCANSWER: pid = ((struct systrace_answer *)data)->stra_pid; if (!pid) ret = EINVAL; break; case STRIOCIO: pid = ((struct systrace_io *)data)->strio_pid; if (!pid) ret = EINVAL; break; case STRIOCGETCWD: pid = *(pid_t *)data; if (!pid) ret = EINVAL; break; case STRIOCATTACH: case STRIOCRESCWD: case STRIOCPOLICY: break; case STRIOCREPLACE: pid = ((struct systrace_replace *)data)->strr_pid; if (!pid) ret = EINVAL; break; default: ret = EINVAL; break; } if (ret) return (ret); systrace_lock(); SYSTRACE_LOCK(fst, curlwp); systrace_unlock(); if (pid) { strp = systrace_findpid(fst, pid); if (strp == NULL) { ret = ESRCH; goto unlock; } } switch (cmd) { case STRIOCATTACH: pid = *(pid_t *)data; if (!pid) ret = EINVAL; else ret = systrace_attach(fst, pid); DPRINTF(("%s: attach to %u: %d\n", __func__, pid, ret)); break; case STRIOCDETACH: ret = systrace_detach(strp); break; case STRIOCREPORT: SET(strp->flags, STR_PROC_REPORT); break; case STRIOCANSWER: ret = systrace_answer(strp, (struct systrace_answer *)data); break; case STRIOCIO: ret = systrace_io(strp, (struct systrace_io *)data); break; case STRIOCPOLICY: ret = systrace_policy(fst, (struct systrace_policy *)data); break; case STRIOCREPLACE: ret = systrace_preprepl(strp, (struct systrace_replace *)data); break; case STRIOCRESCWD: if (!fst->fd_pid) { ret = EINVAL; break; } #ifdef __NetBSD__ cwdp = p->p_cwdi; /* Release cwd from other process */ if (cwdp->cwdi_cdir) vrele(cwdp->cwdi_cdir); if (cwdp->cwdi_rdir) vrele(cwdp->cwdi_rdir); cwdp->cwdi_cdir = fst->fd_cdir; cwdp->cwdi_rdir = fst->fd_rdir; #else fdp = p->p_fd; /* Release cwd from other process */ if (fdp->fd_cdir) vrele(fdp->fd_cdir); if (fdp->fd_rdir) vrele(fdp->fd_rdir); /* This restores the cwd we had before */ fdp->fd_cdir = fst->fd_cdir; fdp->fd_rdir = fst->fd_rdir; #endif /* Note that we are normal again */ fst->fd_pid = 0; fst->fd_cdir = fst->fd_rdir = NULL; break; case STRIOCGETCWD: ret = systrace_getcwd(fst, strp); break; default: ret = EINVAL; break; } unlock: SYSTRACE_UNLOCK(fst, curlwp); return (ret); } #ifdef __NetBSD__ /* ARGSUSED */ int systracef_fcntl(struct file *fp, u_int cmd, void *data, struct proc *p) { if (cmd == FNONBLOCK || cmd == FASYNC) return 0; return (EOPNOTSUPP); } #endif #ifdef __NetBSD__ int systracef_poll(struct file *fp, int events, struct proc *p) { struct fsystrace *fst = (struct fsystrace *)fp->f_data; int revents = 0; if ((events & (POLLIN | POLLRDNORM)) == 0) return (revents); systrace_lock(); SYSTRACE_LOCK(fst, p); systrace_unlock(); if (!TAILQ_EMPTY(&fst->messages)) revents |= events & (POLLIN | POLLRDNORM); if (revents == 0) selrecord(p, &fst->si); SYSTRACE_UNLOCK(fst, p); return (revents); } #else int systracef_select(struct file *fp, int which, struct proc *p) { struct fsystrace *fst = (struct fsystrace *)fp->f_data; int ready = 0; if (which != FREAD) return (0); systrace_lock(); SYSTRACE_LOCK(fst, p); systrace_unlock(); ready = TAILQ_FIRST(&fst->messages) != NULL; if (!ready) selrecord(p, &fst->si); SYSTRACE_UNLOCK(fst, p); return (ready); } #endif /* __NetBSD__ */ /* ARGSUSED */ int systracef_kqfilter(struct file *fp, struct knote *kn) { return (1); } /* ARGSUSED */ int systracef_stat(struct file *fp, struct stat *sb, struct proc *p) { return (EOPNOTSUPP); } /* ARGSUSED */ int systracef_close(struct file *fp, struct proc *p) { struct fsystrace *fst = (struct fsystrace *)fp->f_data; struct str_process *strp; struct str_msgcontainer *cont; struct str_policy *strpol; systrace_lock(); SYSTRACE_LOCK(fst, curlwp); systrace_unlock(); /* Untrace all processes */ for (strp = TAILQ_FIRST(&fst->processes); strp; strp = TAILQ_FIRST(&fst->processes)) { struct proc *q = strp->proc; systrace_detach(strp); psignal(q, SIGKILL); } /* Clean up fork and exit messages */ for (cont = TAILQ_FIRST(&fst->messages); cont; cont = TAILQ_FIRST(&fst->messages)) { TAILQ_REMOVE(&fst->messages, cont, next); pool_put(&systr_msgcontainer_pl, cont); } /* Clean up all policies */ for (strpol = TAILQ_FIRST(&fst->policies); strpol; strpol = TAILQ_FIRST(&fst->policies)) systrace_closepolicy(fst, strpol); /* Release vnodes */ if (fst->fd_cdir) vrele(fst->fd_cdir); if (fst->fd_rdir) vrele(fst->fd_rdir); SYSTRACE_UNLOCK(fst, curlwp); FREE(fp->f_data, M_XDATA); fp->f_data = NULL; return (0); } void systrace_lock(void) { #ifdef __NetBSD__ lockmgr(&systrace_lck, LK_EXCLUSIVE, NULL); #else lockmgr(&systrace_lck, LK_EXCLUSIVE, NULL, curlwp); #endif } void systrace_unlock(void) { #ifdef __NetBSD__ lockmgr(&systrace_lck, LK_RELEASE, NULL); #else lockmgr(&systrace_lck, LK_RELEASE, NULL, curlwp); #endif } void systrace_init(void) { pool_init(&systr_proc_pl, sizeof(struct str_process), 0, 0, 0, "strprocpl", NULL); pool_init(&systr_policy_pl, sizeof(struct str_policy), 0, 0, 0, "strpolpl", NULL); pool_init(&systr_msgcontainer_pl, sizeof(struct str_msgcontainer), 0, 0, 0, "strmsgpl", NULL); lockinit(&systrace_lck, PLOCK, "systrace", 0, 0); } int systraceopen(dev_t dev, int flag, int mode, struct proc *p) { struct fsystrace *fst; struct file *fp; int error, fd; /* falloc() will use the descriptor for us. */ if ((error = falloc(p, &fp, &fd)) != 0) return (error); MALLOC(fst, struct fsystrace *, sizeof(*fst), M_XDATA, M_WAITOK); memset(fst, 0, sizeof(struct fsystrace)); lockinit(&fst->lock, PLOCK, "systrace", 0, 0); TAILQ_INIT(&fst->processes); TAILQ_INIT(&fst->messages); TAILQ_INIT(&fst->policies); if (suser(p->p_ucred, &p->p_acflag) == 0) fst->issuser = 1; fst->p_ruid = p->p_cred->p_ruid; fst->p_rgid = p->p_cred->p_rgid; fp->f_flag = FREAD | FWRITE; fp->f_type = DTYPE_MISC; fp->f_ops = &systracefops; fp->f_data = (caddr_t) fst; p->p_dupfd = fd; FILE_SET_MATURE(fp); FILE_UNUSE(fp, p); return (ENXIO); } void systrace_wakeup(struct fsystrace *fst) { wakeup((caddr_t)fst); selwakeup(&fst->si); } struct proc * systrace_find(struct str_process *strp) { struct proc *proc; if ((proc = pfind(strp->pid)) == NULL) return (NULL); if (proc != strp->proc) return (NULL); if (!ISSET(proc->p_flag, P_SYSTRACE)) return (NULL); return (proc); } void systrace_sys_exit(struct proc *proc) { struct str_process *strp; struct fsystrace *fst; systrace_lock(); strp = proc->p_systrace; if (strp != NULL) { fst = strp->parent; SYSTRACE_LOCK(fst, curlwp); systrace_unlock(); /* Insert Exit message */ systrace_msg_child(fst, strp, -1); systrace_detach(strp); SYSTRACE_UNLOCK(fst, curlwp); } else systrace_unlock(); CLR(proc->p_flag, P_SYSTRACE); } void systrace_sys_fork(struct proc *oldproc, struct proc *p) { struct str_process *oldstrp, *strp; struct fsystrace *fst; systrace_lock(); oldstrp = oldproc->p_systrace; if (oldstrp == NULL) { systrace_unlock(); return; } fst = oldstrp->parent; SYSTRACE_LOCK(fst, curlwp); systrace_unlock(); if (systrace_insert_process(fst, p, &strp)) { /* We need to kill the child */ psignal(p, SIGKILL); goto out; } /* Reference policy */ if ((strp->policy = oldstrp->policy) != NULL) strp->policy->refcount++; /* Insert fork message */ systrace_msg_child(fst, oldstrp, p->p_pid); out: SYSTRACE_UNLOCK(fst, curlwp); } int systrace_enter(struct proc *p, register_t code, void *v, register_t retval[]) { const struct sysent *callp; struct str_process *strp; struct str_policy *strpolicy; struct fsystrace *fst; struct pcred *pc; int policy, error = 0, report = 0, maycontrol = 0, issuser = 0; systrace_lock(); strp = p->p_systrace; if (strp == NULL) { systrace_unlock(); return (EINVAL); } KASSERT(strp->proc == p); fst = strp->parent; SYSTRACE_LOCK(fst, p); systrace_unlock(); /* * We can not monitor a SUID process unless we are root, * but we wait until it executes something unprivileged. * A non-root user may only monitor if the real uid and * real gid match the monitored process. Changing the * uid or gid causes P_SUGID to be set. */ if (fst->issuser) { maycontrol = 1; issuser = 1; } else if (!(p->p_flag & P_SUGID)) { maycontrol = fst->p_ruid == p->p_cred->p_ruid && fst->p_rgid == p->p_cred->p_rgid; } if (!maycontrol) { policy = SYSTR_POLICY_PERMIT; } else { /* Find out current policy */ if ((strpolicy = strp->policy) == NULL) policy = SYSTR_POLICY_ASK; else { if (code >= strpolicy->nsysent) policy = SYSTR_POLICY_NEVER; else policy = strpolicy->sysent[code]; } } callp = p->p_emul->e_sysent + code; /* Fast-path */ if (policy != SYSTR_POLICY_ASK) { if (policy != SYSTR_POLICY_PERMIT) { if (policy > 0) error = policy; else error = EPERM; } strp->oldemul = NULL; SYSTRACE_UNLOCK(fst, p); return (error); } /* Puts the current process to sleep, return unlocked */ error = systrace_msg_ask(fst, strp, code, callp->sy_argsize, v); /* lock has been released in systrace_msg_ask() */ fst = NULL; /* We might have detached by now for some reason */ if (!error && (strp = p->p_systrace) != NULL) { /* XXX - do I need to lock here? */ if (strp->answer == SYSTR_POLICY_NEVER) { error = strp->error; if (strp->replace != NULL) { free(strp->replace, M_XDATA); strp->replace = NULL; } } else { if (ISSET(strp->flags, STR_PROC_SYSCALLRES)) { #ifndef __NetBSD__ CLR(strp->flags, STR_PROC_SYSCALLRES); #endif report = 1; } /* Replace the arguments if necessary */ if (strp->replace != NULL) { error = systrace_replace(strp, callp->sy_argsize, v); } } } systrace_lock(); if ((strp = p->p_systrace) == NULL) goto out; if (error) { strp->oldemul = NULL; goto out; } pc = p->p_cred; strp->oldemul = p->p_emul; strp->olduid = pc->p_ruid; strp->oldgid = pc->p_rgid; /* Elevate privileges as desired */ if (issuser) { if (ISSET(strp->flags, STR_PROC_SETEUID)) strp->saveuid = systrace_seteuid(p, strp->seteuid); if (ISSET(strp->flags, STR_PROC_SETEGID)) strp->savegid = systrace_setegid(p, strp->setegid); } else CLR(strp->flags, STR_PROC_SETEUID|STR_PROC_SETEGID); out: systrace_unlock(); return (error); } void systrace_exit(struct proc *p, register_t code, void *v, register_t retval[], int error) { const struct sysent *callp; struct str_process *strp; struct fsystrace *fst; struct pcred *pc; /* Report change in emulation */ systrace_lock(); strp = p->p_systrace; if (strp == NULL || strp->oldemul == NULL) { systrace_unlock(); return; } DPRINTF(("exit syscall %lu, oldemul %p\n", (u_long)code, strp->oldemul)); /* Return to old privileges */ pc = p->p_cred; if (ISSET(strp->flags, STR_PROC_SETEUID)) { if (pc->pc_ucred->cr_uid == strp->seteuid) systrace_seteuid(p, strp->saveuid); CLR(strp->flags, STR_PROC_SETEUID); } if (ISSET(strp->flags, STR_PROC_SETEGID)) { if (pc->pc_ucred->cr_gid == strp->setegid) systrace_setegid(p, strp->savegid); CLR(strp->flags, STR_PROC_SETEGID); } if (p->p_flag & P_SUGID) { if ((fst = strp->parent) == NULL || !fst->issuser) { systrace_unlock(); return; } } /* See if we should force a report */ if (ISSET(strp->flags, STR_PROC_REPORT)) { CLR(strp->flags, STR_PROC_REPORT); strp->oldemul = NULL; } if (p->p_emul != strp->oldemul && strp != NULL) { fst = strp->parent; SYSTRACE_LOCK(fst, p); systrace_unlock(); /* Old policy is without meaning now */ if (strp->policy) { systrace_closepolicy(fst, strp->policy); strp->policy = NULL; } systrace_msg_emul(fst, strp); } else systrace_unlock(); /* Report if effective uid or gid changed */ systrace_lock(); strp = p->p_systrace; if (strp != NULL && (strp->olduid != p->p_cred->p_ruid || strp->oldgid != p->p_cred->p_rgid)) { fst = strp->parent; SYSTRACE_LOCK(fst, p); systrace_unlock(); systrace_msg_ugid(fst, strp); } else systrace_unlock(); /* Report result from system call */ systrace_lock(); strp = p->p_systrace; if (strp != NULL && ISSET(strp->flags, STR_PROC_SYSCALLRES)) { CLR(strp->flags, STR_PROC_SYSCALLRES); fst = strp->parent; SYSTRACE_LOCK(fst, p); systrace_unlock(); DPRINTF(("will ask syscall %lu, strp %p\n", (u_long)code, strp)); callp = p->p_emul->e_sysent + code; systrace_msg_result(fst, strp, error, code, callp->sy_argsize, v, retval); } else { DPRINTF(("will not ask syscall %lu, strp %p\n", (u_long)code, strp)); systrace_unlock(); } } uid_t systrace_seteuid(struct proc *p, uid_t euid) { struct pcred *pc = p->p_cred; uid_t oeuid = pc->pc_ucred->cr_uid; if (pc->pc_ucred->cr_uid == euid) return (oeuid); /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_uid = euid; p_sugid(p); return (oeuid); } gid_t systrace_setegid(struct proc *p, gid_t egid) { struct pcred *pc = p->p_cred; gid_t oegid = pc->pc_ucred->cr_gid; if (pc->pc_ucred->cr_gid == egid) return (oegid); /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_gid = egid; p_sugid(p); return (oegid); } /* Called with fst locked */ int systrace_answer(struct str_process *strp, struct systrace_answer *ans) { int error = 0; DPRINTF(("%s: %u: policy %d\n", __func__, ans->stra_pid, ans->stra_policy)); if (!POLICY_VALID(ans->stra_policy)) { error = EINVAL; goto out; } /* Check if answer is in sync with us */ if (ans->stra_seqnr != strp->seqnr) { error = ESRCH; goto out; } if ((error = systrace_processready(strp)) != 0) goto out; strp->answer = ans->stra_policy; strp->error = ans->stra_error; if (!strp->error) strp->error = EPERM; if (ISSET(ans->stra_flags, SYSTR_FLAGS_RESULT)) SET(strp->flags, STR_PROC_SYSCALLRES); /* See if we should elevate privileges for this system call */ if (ISSET(ans->stra_flags, SYSTR_FLAGS_SETEUID)) { SET(strp->flags, STR_PROC_SETEUID); strp->seteuid = ans->stra_seteuid; } if (ISSET(ans->stra_flags, SYSTR_FLAGS_SETEGID)) { SET(strp->flags, STR_PROC_SETEGID); strp->setegid = ans->stra_setegid; } /* Clearing the flag indicates to the process that it woke up */ CLR(strp->flags, STR_PROC_WAITANSWER); wakeup(strp); out: return (error); } int systrace_policy(struct fsystrace *fst, struct systrace_policy *pol) { struct str_policy *strpol; struct str_process *strp; switch(pol->strp_op) { case SYSTR_POLICY_NEW: DPRINTF(("%s: new, ents %d\n", __func__, pol->strp_maxents)); if (pol->strp_maxents <= 0 || pol->strp_maxents > 1024) return (EINVAL); strpol = systrace_newpolicy(fst, pol->strp_maxents); if (strpol == NULL) return (ENOBUFS); pol->strp_num = strpol->nr; break; case SYSTR_POLICY_ASSIGN: DPRINTF(("%s: %d -> pid %d\n", __func__, pol->strp_num, pol->strp_pid)); /* Find right policy by number */ TAILQ_FOREACH(strpol, &fst->policies, next) if (strpol->nr == pol->strp_num) break; if (strpol == NULL) return (EINVAL); strp = systrace_findpid(fst, pol->strp_pid); if (strp == NULL) return (EINVAL); /* Check that emulation matches */ if (strpol->emul && strpol->emul != strp->proc->p_emul) return (EINVAL); if (strp->policy) systrace_closepolicy(fst, strp->policy); strp->policy = strpol; strpol->refcount++; /* Record emulation for this policy */ if (strpol->emul == NULL) strpol->emul = strp->proc->p_emul; break; case SYSTR_POLICY_MODIFY: DPRINTF(("%s: %d: code %d -> policy %d\n", __func__, pol->strp_num, pol->strp_code, pol->strp_policy)); if (!POLICY_VALID(pol->strp_policy)) return (EINVAL); TAILQ_FOREACH(strpol, &fst->policies, next) if (strpol->nr == pol->strp_num) break; if (strpol == NULL) return (EINVAL); if (pol->strp_code < 0 || pol->strp_code >= strpol->nsysent) return (EINVAL); strpol->sysent[pol->strp_code] = pol->strp_policy; break; default: return (EINVAL); } return (0); } int systrace_processready(struct str_process *strp) { if (ISSET(strp->flags, STR_PROC_ONQUEUE)) return (EBUSY); if (!ISSET(strp->flags, STR_PROC_WAITANSWER)) return (EBUSY); /* XXX - ignore until systrace knows about lwps. :-( if (strp->proc->p_stat != LSSLEEP) return (EBUSY); */ return (0); } int systrace_getcwd(struct fsystrace *fst, struct str_process *strp) { #ifdef __NetBSD__ struct cwdinfo *mycwdp, *cwdp; #else struct filedesc *myfdp, *fdp; #endif int error; DPRINTF(("%s: %d\n", __func__, strp->pid)); error = systrace_processready(strp); if (error) return (error); #ifdef __NetBSD__ mycwdp = curproc->p_cwdi; cwdp = strp->proc->p_cwdi; if (mycwdp == NULL || cwdp == NULL) return (EINVAL); /* Store our current values */ fst->fd_pid = strp->pid; fst->fd_cdir = mycwdp->cwdi_cdir; fst->fd_rdir = mycwdp->cwdi_rdir; if ((mycwdp->cwdi_cdir = cwdp->cwdi_cdir) != NULL) VREF(mycwdp->cwdi_cdir); if ((mycwdp->cwdi_rdir = cwdp->cwdi_rdir) != NULL) VREF(mycwdp->cwdi_rdir); #else myfdp = curlwp->p_fd; fdp = strp->proc->p_fd; if (myfdp == NULL || fdp == NULL) return (EINVAL); /* Store our current values */ fst->fd_pid = strp->pid; fst->fd_cdir = myfdp->fd_cdir; fst->fd_rdir = myfdp->fd_rdir; if ((myfdp->fd_cdir = fdp->fd_cdir) != NULL) VREF(myfdp->fd_cdir); if ((myfdp->fd_rdir = fdp->fd_rdir) != NULL) VREF(myfdp->fd_rdir); #endif return (0); } int systrace_io(struct str_process *strp, struct systrace_io *io) { struct proc *p = curproc, *t = strp->proc; struct uio uio; struct iovec iov; int error = 0; DPRINTF(("%s: %u: %p(%lu)\n", __func__, io->strio_pid, io->strio_offs, (u_long)io->strio_len)); switch (io->strio_op) { case SYSTR_READ: uio.uio_rw = UIO_READ; break; case SYSTR_WRITE: uio.uio_rw = UIO_WRITE; break; default: return (EINVAL); } error = systrace_processready(strp); if (error) goto out; iov.iov_base = io->strio_addr; iov.iov_len = io->strio_len; uio.uio_iov = &iov; uio.uio_iovcnt = 1; uio.uio_offset = (off_t)(long)io->strio_offs; uio.uio_resid = io->strio_len; uio.uio_segflg = UIO_USERSPACE; uio.uio_procp = p; #ifdef __NetBSD__ error = process_domem(p, t, &uio); #else error = procfs_domem(p, t, NULL, &uio); #endif io->strio_len -= uio.uio_resid; out: return (error); } int systrace_attach(struct fsystrace *fst, pid_t pid) { int error = 0; struct proc *proc, *p = curproc; if ((proc = pfind(pid)) == NULL) { error = ESRCH; goto out; } if (ISSET(proc->p_flag, P_INEXEC)) { error = EAGAIN; goto out; } /* * You can't attach to a process if: * (1) it's the process that's doing the attaching, */ if (proc->p_pid == p->p_pid) { error = EINVAL; goto out; } /* * (2) it's a system process */ if (ISSET(proc->p_flag, P_SYSTEM)) { error = EPERM; goto out; } /* * (3) it's being traced already */ if (ISSET(proc->p_flag, P_SYSTRACE)) { error = EBUSY; goto out; } /* * (4) it's not owned by you, or the last exec * gave us setuid/setgid privs (unless * you're root), or... * * [Note: once P_SUGID gets set in execve(), it stays * set until the process does another execve(). Hence * this prevents a setuid process which revokes it's * special privilidges using setuid() from being * traced. This is good security.] */ if ((proc->p_cred->p_ruid != p->p_cred->p_ruid || ISSET(proc->p_flag, P_SUGID)) && (error = suser(p->p_ucred, &p->p_acflag)) != 0) goto out; /* * (5) ...it's init, which controls the security level * of the entire system, and the system was not * compiled with permanently insecure mode turned * on. */ if ((proc->p_pid == 1) && (securelevel > -1)) { error = EPERM; goto out; } error = systrace_insert_process(fst, proc, NULL); #if defined(__NetBSD__) && defined(__HAVE_SYSCALL_INTERN) /* * Make sure we're using the version of the syscall handler that * has systrace hooks. */ if (!error) (*proc->p_emul->e_syscall_intern)(proc); #endif out: return (error); } /* Prepare to replace arguments */ int systrace_preprepl(struct str_process *strp, struct systrace_replace *repl) { size_t len; int i, ret = 0; ret = systrace_processready(strp); if (ret) return (ret); if (strp->replace != NULL) { free(strp->replace, M_XDATA); strp->replace = NULL; } if (repl->strr_nrepl < 0 || repl->strr_nrepl > SYSTR_MAXARGS) return (EINVAL); for (i = 0, len = 0; i < repl->strr_nrepl; i++) { len += repl->strr_offlen[i]; if (repl->strr_offlen[i] == 0) continue; if (repl->strr_offlen[i] + repl->strr_off[i] > len) return (EINVAL); } /* Make sure that the length adds up */ if (repl->strr_len != len) return (EINVAL); /* Check against a maximum length */ if (repl->strr_len > 2048) return (EINVAL); strp->replace = (struct systrace_replace *) malloc(sizeof(struct systrace_replace) + len, M_XDATA, M_WAITOK); memcpy(strp->replace, repl, sizeof(struct systrace_replace)); ret = copyin(repl->strr_base, strp->replace + 1, len); if (ret) { free(strp->replace, M_XDATA); strp->replace = NULL; return (ret); } /* Adjust the offset */ repl = strp->replace; repl->strr_base = (caddr_t)(repl + 1); return (0); } /* * Replace the arguments with arguments from the monitoring process. */ int systrace_replace(struct str_process *strp, size_t argsize, register_t args[]) { struct proc *p = strp->proc; struct systrace_replace *repl = strp->replace; caddr_t sg, kdata, udata, kbase, ubase; int i, maxarg, ind, ret = 0; maxarg = argsize/sizeof(register_t); #ifdef __NetBSD__ sg = stackgap_init(p, 0); ubase = stackgap_alloc(p, &sg, repl->strr_len); #else sg = stackgap_init(p->p_emul); ubase = stackgap_alloc(&sg, repl->strr_len); #endif kbase = repl->strr_base; for (i = 0; i < maxarg && i < repl->strr_nrepl; i++) { ind = repl->strr_argind[i]; if (ind < 0 || ind >= maxarg) { ret = EINVAL; goto out; } if (repl->strr_offlen[i] == 0) { args[ind] = repl->strr_off[i]; continue; } kdata = kbase + repl->strr_off[i]; udata = ubase + repl->strr_off[i]; if (copyout(kdata, udata, repl->strr_offlen[i])) { ret = EINVAL; goto out; } /* Replace the argument with the new address */ args[ind] = (register_t)(intptr_t)udata; } out: free(repl, M_XDATA); strp->replace = NULL; return (ret); } struct str_process * systrace_findpid(struct fsystrace *fst, pid_t pid) { struct str_process *strp; struct proc *proc = NULL; TAILQ_FOREACH(strp, &fst->processes, next) if (strp->pid == pid) break; if (strp == NULL) return (NULL); proc = systrace_find(strp); return (proc ? strp : NULL); } int systrace_detach(struct str_process *strp) { struct proc *proc; struct fsystrace *fst = NULL; int error = 0; DPRINTF(("%s: Trying to detach from %d\n", __func__, strp->pid)); if ((proc = systrace_find(strp)) != NULL) { CLR(proc->p_flag, P_SYSTRACE); proc->p_systrace = NULL; } else error = ESRCH; if (ISSET(strp->flags, STR_PROC_WAITANSWER)) { CLR(strp->flags, STR_PROC_WAITANSWER); wakeup(strp); } fst = strp->parent; systrace_wakeup(fst); TAILQ_REMOVE(&fst->processes, strp, next); fst->nprocesses--; if (strp->policy) systrace_closepolicy(fst, strp->policy); if (strp->replace) free(strp->replace, M_XDATA); pool_put(&systr_proc_pl, strp); return (error); } void systrace_closepolicy(struct fsystrace *fst, struct str_policy *policy) { if (--policy->refcount) return; fst->npolicies--; if (policy->nsysent) free(policy->sysent, M_XDATA); TAILQ_REMOVE(&fst->policies, policy, next); pool_put(&systr_policy_pl, policy); } int systrace_insert_process(struct fsystrace *fst, struct proc *proc, struct str_process **pstrp) { struct str_process *strp; strp = pool_get(&systr_proc_pl, PR_NOWAIT); if (strp == NULL) return (ENOBUFS); memset((caddr_t)strp, 0, sizeof(struct str_process)); strp->pid = proc->p_pid; strp->proc = proc; strp->parent = fst; TAILQ_INSERT_TAIL(&fst->processes, strp, next); fst->nprocesses++; proc->p_systrace = strp; SET(proc->p_flag, P_SYSTRACE); /* Pass the new pointer back to the caller */ if (pstrp != NULL) *pstrp = strp; return (0); } struct str_policy * systrace_newpolicy(struct fsystrace *fst, int maxents) { struct str_policy *pol; int i; if (fst->npolicies > SYSTR_MAX_POLICIES && !fst->issuser) { struct str_policy *tmp; /* Try to find a policy for freeing */ TAILQ_FOREACH(tmp, &fst->policies, next) { if (tmp->refcount == 1) break; } if (tmp == NULL) return (NULL); /* Notify userland about freed policy */ systrace_msg_policyfree(fst, tmp); /* Free this policy */ systrace_closepolicy(fst, tmp); } pol = pool_get(&systr_policy_pl, PR_NOWAIT); if (pol == NULL) return (NULL); DPRINTF(("%s: allocating %d -> %lu\n", __func__, maxents, (u_long)maxents * sizeof(int))); memset((caddr_t)pol, 0, sizeof(struct str_policy)); pol->sysent = (u_char *)malloc(maxents * sizeof(u_char), M_XDATA, M_WAITOK); pol->nsysent = maxents; for (i = 0; i < maxents; i++) pol->sysent[i] = SYSTR_POLICY_ASK; fst->npolicies++; pol->nr = fst->npolicynr++; pol->refcount = 1; TAILQ_INSERT_TAIL(&fst->policies, pol, next); return (pol); } int systrace_msg_ask(struct fsystrace *fst, struct str_process *strp, int code, size_t argsize, register_t args[]) { struct str_message msg; struct str_msg_ask *msg_ask = &msg.msg_data.msg_ask; int i; msg_ask->code = code; msg_ask->argsize = argsize; for (i = 0; i < (argsize/sizeof(register_t)) && i < SYSTR_MAXARGS; i++) msg_ask->args[i] = args[i]; return (systrace_make_msg(strp, SYSTR_MSG_ASK, &msg)); } int systrace_msg_result(struct fsystrace *fst, struct str_process *strp, int error, int code, size_t argsize, register_t args[], register_t rval[]) { struct str_message msg; struct str_msg_ask *msg_ask = &msg.msg_data.msg_ask; int i; msg_ask->code = code; msg_ask->argsize = argsize; msg_ask->result = error; for (i = 0; i < (argsize/sizeof(register_t)) && i < SYSTR_MAXARGS; i++) msg_ask->args[i] = args[i]; msg_ask->rval[0] = rval[0]; msg_ask->rval[1] = rval[1]; return (systrace_make_msg(strp, SYSTR_MSG_RES, &msg)); } int systrace_msg_emul(struct fsystrace *fst, struct str_process *strp) { struct str_message msg; struct str_msg_emul *msg_emul = &msg.msg_data.msg_emul; struct proc *p = strp->proc; memcpy(msg_emul->emul, p->p_emul->e_name, SYSTR_EMULEN); return (systrace_make_msg(strp, SYSTR_MSG_EMUL, &msg)); } int systrace_msg_ugid(struct fsystrace *fst, struct str_process *strp) { struct str_message msg; struct str_msg_ugid *msg_ugid = &msg.msg_data.msg_ugid; struct proc *p = strp->proc; msg_ugid->uid = p->p_cred->p_ruid; msg_ugid->gid = p->p_cred->p_rgid; return (systrace_make_msg(strp, SYSTR_MSG_UGID, &msg)); } int systrace_make_msg(struct str_process *strp, int type, struct str_message *tmsg) { struct str_msgcontainer *cont; struct str_message *msg; struct fsystrace *fst = strp->parent; int st; cont = pool_get(&systr_msgcontainer_pl, PR_WAITOK); memset(cont, 0, sizeof(struct str_msgcontainer)); cont->strp = strp; msg = &cont->msg; /* Copy the already filled in fields */ memcpy(&msg->msg_data, &tmsg->msg_data, sizeof(msg->msg_data)); /* Add the extra fields to the message */ msg->msg_seqnr = ++strp->seqnr; msg->msg_type = type; msg->msg_pid = strp->pid; if (strp->policy) msg->msg_policy = strp->policy->nr; else msg->msg_policy = -1; SET(strp->flags, STR_PROC_WAITANSWER); if (ISSET(strp->flags, STR_PROC_ONQUEUE)) goto out; TAILQ_INSERT_TAIL(&fst->messages, cont, next); SET(strp->flags, STR_PROC_ONQUEUE); out: systrace_wakeup(fst); /* Release the lock - XXX */ SYSTRACE_UNLOCK(fst, strp->proc); while (1) { st = tsleep(strp, PWAIT | PCATCH, "systrmsg", 0); if (st != 0) return (ERESTART); /* If we detach, then everything is permitted */ if ((strp = curproc->p_systrace) == NULL) return (0); if (!ISSET(strp->flags, STR_PROC_WAITANSWER)) break; } return (0); } int systrace_msg_child(struct fsystrace *fst, struct str_process *strp, pid_t npid) { struct str_msgcontainer *cont; struct str_message *msg; struct str_msg_child *msg_child; cont = pool_get(&systr_msgcontainer_pl, PR_WAITOK); memset(cont, 0, sizeof(struct str_msgcontainer)); cont->strp = strp; msg = &cont->msg; DPRINTF(("%s: %p: pid %d -> pid %d\n", __func__, msg, strp->pid, npid)); msg_child = &msg->msg_data.msg_child; msg->msg_type = SYSTR_MSG_CHILD; msg->msg_pid = strp->pid; if (strp->policy) msg->msg_policy = strp->policy->nr; else msg->msg_policy = -1; msg_child->new_pid = npid; TAILQ_INSERT_TAIL(&fst->messages, cont, next); systrace_wakeup(fst); return (0); } int systrace_msg_policyfree(struct fsystrace *fst, struct str_policy *strpol) { struct str_msgcontainer *cont; struct str_message *msg; cont = pool_get(&systr_msgcontainer_pl, PR_WAITOK); memset(cont, 0, sizeof(struct str_msgcontainer)); msg = &cont->msg; DPRINTF(("%s: free %d\n", __func__, strpol->nr)); msg->msg_type = SYSTR_MSG_POLICYFREE; msg->msg_policy = strpol->nr; TAILQ_INSERT_TAIL(&fst->messages, cont, next); systrace_wakeup(fst); return (0); }