/* $NetBSD: kern_exec.c,v 1.252 2007/11/07 00:23:20 ad Exp $ */ /*- * Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou * Copyright (C) 1992 Wolfgang Solfrank. * Copyright (C) 1992 TooLs GmbH. * 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 TooLs GmbH. * 4. The name of TooLs GmbH may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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_exec.c,v 1.252 2007/11/07 00:23:20 ad Exp $"); #include "opt_ktrace.h" #include "opt_syscall_debug.h" #include "opt_compat_netbsd.h" #include "veriexec.h" #include "opt_pax.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if NVERIEXEC > 0 #include #endif /* NVERIEXEC > 0 */ #ifdef SYSTRACE #include #endif /* SYSTRACE */ #ifdef PAX_SEGVGUARD #include #endif /* PAX_SEGVGUARD */ #include #include #include #include static int exec_sigcode_map(struct proc *, const struct emul *); #ifdef DEBUG_EXEC #define DPRINTF(a) uprintf a #else #define DPRINTF(a) #endif /* DEBUG_EXEC */ MALLOC_DEFINE(M_EXEC, "exec", "argument lists & other mem used by exec"); /* * Exec function switch: * * Note that each makecmds function is responsible for loading the * exec package with the necessary functions for any exec-type-specific * handling. * * Functions for specific exec types should be defined in their own * header file. */ extern const struct execsw execsw_builtin[]; extern int nexecs_builtin; static const struct execsw **execsw = NULL; static int nexecs; u_int exec_maxhdrsz; /* must not be static - netbsd32 needs it */ #ifdef LKM /* list of supported emulations */ static LIST_HEAD(emlist_head, emul_entry) el_head = LIST_HEAD_INITIALIZER(el_head); struct emul_entry { LIST_ENTRY(emul_entry) el_list; const struct emul *el_emul; int ro_entry; }; /* list of dynamically loaded execsw entries */ static LIST_HEAD(execlist_head, exec_entry) ex_head = LIST_HEAD_INITIALIZER(ex_head); struct exec_entry { LIST_ENTRY(exec_entry) ex_list; const struct execsw *es; }; /* structure used for building execw[] */ struct execsw_entry { struct execsw_entry *next; const struct execsw *es; }; #endif /* LKM */ #ifdef SYSCALL_DEBUG extern const char * const syscallnames[]; #endif #ifdef COMPAT_16 extern char sigcode[], esigcode[]; struct uvm_object *emul_netbsd_object; #endif #ifndef __HAVE_SYSCALL_INTERN void syscall(void); #endif /* NetBSD emul struct */ const struct emul emul_netbsd = { "netbsd", NULL, /* emulation path */ #ifndef __HAVE_MINIMAL_EMUL EMUL_HAS_SYS___syscall, NULL, SYS_syscall, SYS_NSYSENT, #endif sysent, #ifdef SYSCALL_DEBUG syscallnames, #else NULL, #endif sendsig, trapsignal, NULL, #ifdef COMPAT_16 sigcode, esigcode, &emul_netbsd_object, #else NULL, NULL, NULL, #endif setregs, NULL, NULL, NULL, NULL, NULL, #ifdef __HAVE_SYSCALL_INTERN syscall_intern, #else syscall, #endif NULL, NULL, uvm_default_mapaddr, NULL, sizeof(ucontext_t), startlwp, }; #ifdef LKM /* * Exec lock. Used to control access to execsw[] structures. * This must not be static so that netbsd32 can access it, too. */ krwlock_t exec_lock; static void link_es(struct execsw_entry **, const struct execsw *); #endif /* LKM */ /* * check exec: * given an "executable" described in the exec package's namei info, * see what we can do with it. * * ON ENTRY: * exec package with appropriate namei info * lwp pointer of exec'ing lwp * NO SELF-LOCKED VNODES * * ON EXIT: * error: nothing held, etc. exec header still allocated. * ok: filled exec package, executable's vnode (unlocked). * * EXEC SWITCH ENTRY: * Locked vnode to check, exec package, proc. * * EXEC SWITCH EXIT: * ok: return 0, filled exec package, executable's vnode (unlocked). * error: destructive: * everything deallocated execept exec header. * non-destructive: * error code, executable's vnode (unlocked), * exec header unmodified. */ int /*ARGSUSED*/ check_exec(struct lwp *l, struct exec_package *epp) { int error, i; struct vnode *vp; struct nameidata *ndp; size_t resid; ndp = epp->ep_ndp; ndp->ni_cnd.cn_nameiop = LOOKUP; ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME | TRYEMULROOT; /* first get the vnode */ if ((error = namei(ndp)) != 0) return error; epp->ep_vp = vp = ndp->ni_vp; /* check access and type */ if (vp->v_type != VREG) { error = EACCES; goto bad1; } if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred, l)) != 0) goto bad1; /* get attributes */ if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred, l)) != 0) goto bad1; /* Check mount point */ if (vp->v_mount->mnt_flag & MNT_NOEXEC) { error = EACCES; goto bad1; } if (vp->v_mount->mnt_flag & MNT_NOSUID) epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); /* try to open it */ if ((error = VOP_OPEN(vp, FREAD, l->l_cred, l)) != 0) goto bad1; /* unlock vp, since we need it unlocked from here on out. */ VOP_UNLOCK(vp, 0); #if NVERIEXEC > 0 error = veriexec_verify(l, vp, ndp->ni_cnd.cn_pnbuf, epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT, NULL); if (error) goto bad2; #endif /* NVERIEXEC > 0 */ #ifdef PAX_SEGVGUARD error = pax_segvguard(l, vp, ndp->ni_cnd.cn_pnbuf, false); if (error) goto bad2; #endif /* PAX_SEGVGUARD */ /* now we have the file, get the exec header */ error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, UIO_SYSSPACE, 0, l->l_cred, &resid, NULL); if (error) goto bad2; epp->ep_hdrvalid = epp->ep_hdrlen - resid; /* * Set up default address space limits. Can be overridden * by individual exec packages. * * XXX probably should be all done in the exec packages. */ epp->ep_vm_minaddr = VM_MIN_ADDRESS; epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS; /* * set up the vmcmds for creation of the process * address space */ error = ENOEXEC; for (i = 0; i < nexecs; i++) { int newerror; epp->ep_esch = execsw[i]; newerror = (*execsw[i]->es_makecmds)(l, epp); if (!newerror) { /* Seems ok: check that entry point is sane */ if (epp->ep_entry > VM_MAXUSER_ADDRESS) { error = ENOEXEC; break; } /* check limits */ if ((epp->ep_tsize > MAXTSIZ) || (epp->ep_dsize > (u_quad_t)l->l_proc->p_rlimit [RLIMIT_DATA].rlim_cur)) { error = ENOMEM; break; } return 0; } if (epp->ep_emul_root != NULL) { vrele(epp->ep_emul_root); epp->ep_emul_root = NULL; } if (epp->ep_interp != NULL) { vrele(epp->ep_interp); epp->ep_interp = NULL; } /* make sure the first "interesting" error code is saved. */ if (error == ENOEXEC) error = newerror; if (epp->ep_flags & EXEC_DESTR) /* Error from "#!" code, tidied up by recursive call */ return error; } /* not found, error */ /* * free any vmspace-creation commands, * and release their references */ kill_vmcmds(&epp->ep_vmcmds); bad2: /* * close and release the vnode, restore the old one, free the * pathname buf, and punt. */ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(vp, FREAD, l->l_cred, l); vput(vp); PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); return error; bad1: /* * free the namei pathname buffer, and put the vnode * (which we don't yet have open). */ vput(vp); /* was still locked */ PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); return error; } #ifdef __MACHINE_STACK_GROWS_UP #define STACK_PTHREADSPACE NBPG #else #define STACK_PTHREADSPACE 0 #endif static int execve_fetch_element(char * const *array, size_t index, char **value) { return copyin(array + index, value, sizeof(*value)); } /* * exec system call */ /* ARGSUSED */ int sys_execve(struct lwp *l, void *v, register_t *retval) { struct sys_execve_args /* { syscallarg(const char *) path; syscallarg(char * const *) argp; syscallarg(char * const *) envp; } */ *uap = v; return execve1(l, SCARG(uap, path), SCARG(uap, argp), SCARG(uap, envp), execve_fetch_element); } int execve1(struct lwp *l, const char *path, char * const *args, char * const *envs, execve_fetch_element_t fetch_element) { int error; struct exec_package pack; struct nameidata nid; struct vattr attr; struct proc *p; char *argp; char *dp, *sp; long argc, envc; size_t i, len; char *stack; struct ps_strings arginfo; struct ps_strings *aip = &arginfo; struct vmspace *vm; char **tmpfap; int szsigcode; struct exec_vmcmd *base_vcp; ksiginfo_t ksi; ksiginfoq_t kq; #ifdef SYSTRACE int wassugid = ISSET(p->p_flag, PK_SUGID); char pathbuf[MAXPATHLEN]; size_t pathbuflen; #endif /* SYSTRACE */ p = l->l_proc; /* * Drain existing references and forbid new ones. The process * should be left alone until we're done here. This is necessary * to avoid race conditions - e.g. in ptrace() - that might allow * a local user to illicitly obtain elevated privileges. */ rw_enter(&p->p_reflock, RW_WRITER); base_vcp = NULL; /* * Init the namei data to point the file user's program name. * This is done here rather than in check_exec(), so that it's * possible to override this settings if any of makecmd/probe * functions call check_exec() recursively - for example, * see exec_script_makecmds(). */ #ifdef SYSTRACE if (ISSET(p->p_flag, PK_SYSTRACE)) systrace_execve0(p); error = copyinstr(path, pathbuf, sizeof(pathbuf), &pathbuflen); if (error) { DPRINTF(("execve: copyinstr path %d", error)); goto clrflg; } NDINIT(&nid, LOOKUP, NOFOLLOW | TRYEMULROOT, UIO_SYSSPACE, pathbuf, l); #else NDINIT(&nid, LOOKUP, NOFOLLOW | TRYEMULROOT, UIO_USERSPACE, path, l); #endif /* SYSTRACE */ /* * initialize the fields of the exec package. */ #ifdef SYSTRACE pack.ep_name = pathbuf; #else pack.ep_name = path; #endif /* SYSTRACE */ pack.ep_hdr = malloc(exec_maxhdrsz, M_EXEC, M_WAITOK); pack.ep_hdrlen = exec_maxhdrsz; pack.ep_hdrvalid = 0; pack.ep_ndp = &nid; pack.ep_emul_arg = NULL; pack.ep_vmcmds.evs_cnt = 0; pack.ep_vmcmds.evs_used = 0; pack.ep_vap = &attr; pack.ep_flags = 0; pack.ep_emul_root = NULL; pack.ep_interp = NULL; pack.ep_esch = NULL; #ifdef LKM rw_enter(&exec_lock, RW_READER); #endif /* see if we can run it. */ if ((error = check_exec(l, &pack)) != 0) { DPRINTF(("execve: check exec failed %d\n", error)); goto freehdr; } /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ /* allocate an argument buffer */ argp = (char *) uvm_km_alloc(exec_map, NCARGS, 0, UVM_KMF_PAGEABLE|UVM_KMF_WAITVA); #ifdef DIAGNOSTIC if (argp == NULL) panic("execve: argp == NULL"); #endif dp = argp; argc = 0; /* copy the fake args list, if there's one, freeing it as we go */ if (pack.ep_flags & EXEC_HASARGL) { tmpfap = pack.ep_fa; while (*tmpfap != NULL) { char *cp; cp = *tmpfap; while (*cp) *dp++ = *cp++; dp++; FREE(*tmpfap, M_EXEC); tmpfap++; argc++; } FREE(pack.ep_fa, M_EXEC); pack.ep_flags &= ~EXEC_HASARGL; } /* Now get argv & environment */ if (args == NULL) { DPRINTF(("execve: null args\n")); error = EINVAL; goto bad; } /* 'i' will index the argp/envp element to be retrieved */ i = 0; if (pack.ep_flags & EXEC_SKIPARG) i++; while (1) { len = argp + ARG_MAX - dp; if ((error = (*fetch_element)(args, i, &sp)) != 0) { DPRINTF(("execve: fetch_element args %d\n", error)); goto bad; } if (!sp) break; if ((error = copyinstr(sp, dp, len, &len)) != 0) { DPRINTF(("execve: copyinstr args %d\n", error)); if (error == ENAMETOOLONG) error = E2BIG; goto bad; } ktrexecarg(dp, len - 1); dp += len; i++; argc++; } envc = 0; /* environment need not be there */ if (envs != NULL) { i = 0; while (1) { len = argp + ARG_MAX - dp; if ((error = (*fetch_element)(envs, i, &sp)) != 0) { DPRINTF(("execve: fetch_element env %d\n", error)); goto bad; } if (!sp) break; if ((error = copyinstr(sp, dp, len, &len)) != 0) { DPRINTF(("execve: copyinstr env %d\n", error)); if (error == ENAMETOOLONG) error = E2BIG; goto bad; } ktrexecenv(dp, len - 1); dp += len; i++; envc++; } } dp = (char *) ALIGN(dp); szsigcode = pack.ep_esch->es_emul->e_esigcode - pack.ep_esch->es_emul->e_sigcode; /* Now check if args & environ fit into new stack */ if (pack.ep_flags & EXEC_32) len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * sizeof(int) + sizeof(int) + dp + STACKGAPLEN + szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) - argp; else len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * sizeof(char *) + sizeof(int) + dp + STACKGAPLEN + szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) - argp; #ifdef STACKLALIGN /* arm, etc. */ len = STACKALIGN(len); /* make the stack "safely" aligned */ #else len = ALIGN(len); /* make the stack "safely" aligned */ #endif if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ DPRINTF(("execve: stack limit exceeded %zu\n", len)); error = ENOMEM; goto bad; } /* Get rid of other LWPs. */ if (p->p_nlwps > 1) { mutex_enter(&p->p_smutex); exit_lwps(l); mutex_exit(&p->p_smutex); } KDASSERT(p->p_nlwps == 1); /* This is now LWP 1 */ l->l_lid = 1; p->p_nlwpid = 1; /* Remove POSIX timers */ timers_free(p, TIMERS_POSIX); /* adjust "active stack depth" for process VSZ */ pack.ep_ssize = len; /* maybe should go elsewhere, but... */ /* * Do whatever is necessary to prepare the address space * for remapping. Note that this might replace the current * vmspace with another! */ uvmspace_exec(l, pack.ep_vm_minaddr, pack.ep_vm_maxaddr); /* record proc's vnode, for use by procfs and others */ if (p->p_textvp) vrele(p->p_textvp); VREF(pack.ep_vp); p->p_textvp = pack.ep_vp; /* Now map address space */ vm = p->p_vmspace; vm->vm_taddr = (void *)pack.ep_taddr; vm->vm_tsize = btoc(pack.ep_tsize); vm->vm_daddr = (void*)pack.ep_daddr; vm->vm_dsize = btoc(pack.ep_dsize); vm->vm_ssize = btoc(pack.ep_ssize); vm->vm_maxsaddr = (void *)pack.ep_maxsaddr; vm->vm_minsaddr = (void *)pack.ep_minsaddr; /* create the new process's VM space by running the vmcmds */ #ifdef DIAGNOSTIC if (pack.ep_vmcmds.evs_used == 0) panic("execve: no vmcmds"); #endif for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { struct exec_vmcmd *vcp; vcp = &pack.ep_vmcmds.evs_cmds[i]; if (vcp->ev_flags & VMCMD_RELATIVE) { #ifdef DIAGNOSTIC if (base_vcp == NULL) panic("execve: relative vmcmd with no base"); if (vcp->ev_flags & VMCMD_BASE) panic("execve: illegal base & relative vmcmd"); #endif vcp->ev_addr += base_vcp->ev_addr; } error = (*vcp->ev_proc)(l, vcp); #ifdef DEBUG_EXEC if (error) { size_t j; struct exec_vmcmd *vp = &pack.ep_vmcmds.evs_cmds[0]; for (j = 0; j <= i; j++) uprintf( "vmcmd[%zu] = %#lx/%#lx fd@%#lx prot=0%o flags=%d\n", j, vp[j].ev_addr, vp[j].ev_len, vp[j].ev_offset, vp[j].ev_prot, vp[j].ev_flags); } #endif /* DEBUG_EXEC */ if (vcp->ev_flags & VMCMD_BASE) base_vcp = vcp; } /* free the vmspace-creation commands, and release their references */ kill_vmcmds(&pack.ep_vmcmds); vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred, l); vput(pack.ep_vp); /* if an error happened, deallocate and punt */ if (error) { DPRINTF(("execve: vmcmd %zu failed: %d\n", i - 1, error)); goto exec_abort; } /* remember information about the process */ arginfo.ps_nargvstr = argc; arginfo.ps_nenvstr = envc; stack = (char *)STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, STACK_PTHREADSPACE + sizeof(struct ps_strings) + szsigcode), len - (sizeof(struct ps_strings) + szsigcode)); #ifdef __MACHINE_STACK_GROWS_UP /* * The copyargs call always copies into lower addresses * first, moving towards higher addresses, starting with * the stack pointer that we give. When the stack grows * down, this puts argc/argv/envp very shallow on the * stack, right at the first user stack pointer, and puts * STACKGAPLEN very deep in the stack. When the stack * grows up, the situation is reversed. * * Normally, this is no big deal. But the ld_elf.so _rtld() * function expects to be called with a single pointer to * a region that has a few words it can stash values into, * followed by argc/argv/envp. When the stack grows down, * it's easy to decrement the stack pointer a little bit to * allocate the space for these few words and pass the new * stack pointer to _rtld. When the stack grows up, however, * a few words before argc is part of the signal trampoline, XXX * so we have a problem. * * Instead of changing how _rtld works, we take the easy way * out and steal 32 bytes before we call copyargs. This * space is effectively stolen from STACKGAPLEN. */ stack += 32; #endif /* __MACHINE_STACK_GROWS_UP */ /* Now copy argc, args & environ to new stack */ error = (*pack.ep_esch->es_copyargs)(l, &pack, &arginfo, &stack, argp); if (error) { DPRINTF(("execve: copyargs failed %d\n", error)); goto exec_abort; } /* Move the stack back to original point */ stack = (char *)STACK_GROW(vm->vm_minsaddr, len); /* fill process ps_strings info */ p->p_psstr = (struct ps_strings *) STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, STACK_PTHREADSPACE), sizeof(struct ps_strings)); p->p_psargv = offsetof(struct ps_strings, ps_argvstr); p->p_psnargv = offsetof(struct ps_strings, ps_nargvstr); p->p_psenv = offsetof(struct ps_strings, ps_envstr); p->p_psnenv = offsetof(struct ps_strings, ps_nenvstr); /* copy out the process's ps_strings structure */ if ((error = copyout(aip, (char *)p->p_psstr, sizeof(arginfo))) != 0) { DPRINTF(("execve: ps_strings copyout %p->%p size %ld failed\n", aip, (char *)p->p_psstr, (long)sizeof(arginfo))); goto exec_abort; } fdcloseexec(l); /* handle close on exec */ execsigs(p); /* reset catched signals */ l->l_ctxlink = NULL; /* reset ucontext link */ /* set command name & other accounting info */ i = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, i); p->p_comm[i] = '\0'; p->p_acflag &= ~AFORK; p->p_flag |= PK_EXEC; /* * Stop profiling. */ if ((p->p_stflag & PST_PROFIL) != 0) { mutex_spin_enter(&p->p_stmutex); stopprofclock(p); mutex_spin_exit(&p->p_stmutex); } /* * It's OK to test PS_PPWAIT unlocked here, as other LWPs have * exited and exec()/exit() are the only places it will be cleared. */ if ((p->p_sflag & PS_PPWAIT) != 0) { mutex_enter(&proclist_lock); mutex_enter(&p->p_smutex); p->p_sflag &= ~PS_PPWAIT; cv_broadcast(&p->p_pptr->p_waitcv); mutex_exit(&p->p_smutex); mutex_exit(&proclist_lock); } /* * Deal with set[ug]id. MNT_NOSUID has already been used to disable * s[ug]id. It's OK to check for PSL_TRACED here as we have blocked * out additional references on the process for the moment. */ if ((p->p_slflag & PSL_TRACED) == 0 && (((attr.va_mode & S_ISUID) != 0 && kauth_cred_geteuid(l->l_cred) != attr.va_uid) || ((attr.va_mode & S_ISGID) != 0 && kauth_cred_getegid(l->l_cred) != attr.va_gid))) { /* * Mark the process as SUGID before we do * anything that might block. */ proc_crmod_enter(); proc_crmod_leave(NULL, NULL, true); /* Make sure file descriptors 0..2 are in use. */ if ((error = fdcheckstd(l)) != 0) { DPRINTF(("execve: fdcheckstd failed %d\n", error)); goto exec_abort; } /* * Copy the credential so other references don't see our * changes. */ l->l_cred = kauth_cred_copy(l->l_cred); #ifdef KTRACE /* * If process is being ktraced, turn off - unless * root set it. */ if (p->p_tracep) { mutex_enter(&ktrace_lock); if (!(p->p_traceflag & KTRFAC_ROOT)) ktrderef(p); mutex_exit(&ktrace_lock); } #endif if (attr.va_mode & S_ISUID) kauth_cred_seteuid(l->l_cred, attr.va_uid); if (attr.va_mode & S_ISGID) kauth_cred_setegid(l->l_cred, attr.va_gid); } else { if (kauth_cred_geteuid(l->l_cred) == kauth_cred_getuid(l->l_cred) && kauth_cred_getegid(l->l_cred) == kauth_cred_getgid(l->l_cred)) p->p_flag &= ~PK_SUGID; } /* * Copy the credential so other references don't see our changes. * Test to see if this is necessary first, since in the common case * we won't need a private reference. */ if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) || kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) { l->l_cred = kauth_cred_copy(l->l_cred); kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred)); kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred)); } /* Update the master credentials. */ if (l->l_cred != p->p_cred) { kauth_cred_t ocred; kauth_cred_hold(l->l_cred); mutex_enter(&p->p_mutex); ocred = p->p_cred; p->p_cred = l->l_cred; mutex_exit(&p->p_mutex); kauth_cred_free(ocred); } #if defined(__HAVE_RAS) /* * Remove all RASs from the address space. */ ras_purgeall(); #endif doexechooks(p); uvm_km_free(exec_map, (vaddr_t) argp, NCARGS, UVM_KMF_PAGEABLE); PNBUF_PUT(nid.ni_cnd.cn_pnbuf); /* notify others that we exec'd */ KNOTE(&p->p_klist, NOTE_EXEC); /* setup new registers and do misc. setup. */ (*pack.ep_esch->es_emul->e_setregs)(l, &pack, (u_long) stack); if (pack.ep_esch->es_setregs) (*pack.ep_esch->es_setregs)(l, &pack, (u_long) stack); /* map the process's signal trampoline code */ if (exec_sigcode_map(p, pack.ep_esch->es_emul)) { DPRINTF(("execve: map sigcode failed %d\n", error)); goto exec_abort; } free(pack.ep_hdr, M_EXEC); /* The emulation root will usually have been found when we looked * for the elf interpreter (or similar), if not look now. */ if (pack.ep_esch->es_emul->e_path != NULL && pack.ep_emul_root == NULL) emul_find_root(l, &pack); /* Any old emulation root got removed by fdcloseexec */ p->p_cwdi->cwdi_edir = pack.ep_emul_root; pack.ep_emul_root = NULL; if (pack.ep_interp != NULL) vrele(pack.ep_interp); /* * Call emulation specific exec hook. This can setup per-process * p->p_emuldata or do any other per-process stuff an emulation needs. * * If we are executing process of different emulation than the * original forked process, call e_proc_exit() of the old emulation * first, then e_proc_exec() of new emulation. If the emulation is * same, the exec hook code should deallocate any old emulation * resources held previously by this process. */ if (p->p_emul && p->p_emul->e_proc_exit && p->p_emul != pack.ep_esch->es_emul) (*p->p_emul->e_proc_exit)(p); /* * Call exec hook. Emulation code may NOT store reference to anything * from &pack. */ if (pack.ep_esch->es_emul->e_proc_exec) (*pack.ep_esch->es_emul->e_proc_exec)(p, &pack); /* update p_emul, the old value is no longer needed */ p->p_emul = pack.ep_esch->es_emul; /* ...and the same for p_execsw */ p->p_execsw = pack.ep_esch; #ifdef __HAVE_SYSCALL_INTERN (*p->p_emul->e_syscall_intern)(p); #endif ktremul(); /* Allow new references from the debugger/procfs. */ rw_exit(&p->p_reflock); #ifdef LKM rw_exit(&exec_lock); #endif mutex_enter(&proclist_mutex); if ((p->p_slflag & (PSL_TRACED|PSL_SYSCALL)) == PSL_TRACED) { KSI_INIT_EMPTY(&ksi); ksi.ksi_signo = SIGTRAP; ksi.ksi_lid = l->l_lid; kpsignal(p, &ksi, NULL); } if (p->p_sflag & PS_STOPEXEC) { KERNEL_UNLOCK_ALL(l, &l->l_biglocks); p->p_pptr->p_nstopchild++; p->p_pptr->p_waited = 0; mutex_enter(&p->p_smutex); ksiginfo_queue_init(&kq); sigclearall(p, &contsigmask, &kq); lwp_lock(l); l->l_stat = LSSTOP; p->p_stat = SSTOP; p->p_nrlwps--; mutex_exit(&p->p_smutex); mutex_exit(&proclist_mutex); mi_switch(l); ksiginfo_queue_drain(&kq); KERNEL_LOCK(l->l_biglocks, l); } else { mutex_exit(&proclist_mutex); } #ifdef SYSTRACE /* XXXSMP */ if (ISSET(p->p_flag, PK_SYSTRACE) && wassugid && !ISSET(p->p_flag, PK_SUGID)) systrace_execve1(pathbuf, p); #endif /* SYSTRACE */ return (EJUSTRETURN); bad: /* free the vmspace-creation commands, and release their references */ kill_vmcmds(&pack.ep_vmcmds); /* kill any opened file descriptor, if necessary */ if (pack.ep_flags & EXEC_HASFD) { pack.ep_flags &= ~EXEC_HASFD; (void) fdrelease(l, pack.ep_fd); } /* close and put the exec'd file */ vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred, l); vput(pack.ep_vp); PNBUF_PUT(nid.ni_cnd.cn_pnbuf); uvm_km_free(exec_map, (vaddr_t) argp, NCARGS, UVM_KMF_PAGEABLE); freehdr: free(pack.ep_hdr, M_EXEC); if (pack.ep_emul_root != NULL) vrele(pack.ep_emul_root); if (pack.ep_interp != NULL) vrele(pack.ep_interp); #ifdef SYSTRACE clrflg: #endif /* SYSTRACE */ rw_exit(&p->p_reflock); #ifdef LKM rw_exit(&exec_lock); #endif return error; exec_abort: rw_exit(&p->p_reflock); #ifdef LKM rw_exit(&exec_lock); #endif /* * the old process doesn't exist anymore. exit gracefully. * get rid of the (new) address space we have created, if any, get rid * of our namei data and vnode, and exit noting failure */ uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); if (pack.ep_emul_arg) FREE(pack.ep_emul_arg, M_TEMP); PNBUF_PUT(nid.ni_cnd.cn_pnbuf); uvm_km_free(exec_map, (vaddr_t) argp, NCARGS, UVM_KMF_PAGEABLE); free(pack.ep_hdr, M_EXEC); if (pack.ep_emul_root != NULL) vrele(pack.ep_emul_root); if (pack.ep_interp != NULL) vrele(pack.ep_interp); /* Acquire the sched-state mutex (exit1() will release it). */ mutex_enter(&p->p_smutex); exit1(l, W_EXITCODE(error, SIGABRT)); /* NOTREACHED */ return 0; } int copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo, char **stackp, void *argp) { char **cpp, *dp, *sp; size_t len; void *nullp; long argc, envc; int error; cpp = (char **)*stackp; nullp = NULL; argc = arginfo->ps_nargvstr; envc = arginfo->ps_nenvstr; if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) return error; dp = (char *) (cpp + argc + envc + 2 + pack->ep_esch->es_arglen); sp = argp; /* XXX don't copy them out, remap them! */ arginfo->ps_argvstr = cpp; /* remember location of argv for later */ for (; --argc >= 0; sp += len, dp += len) if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) return error; if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) return error; arginfo->ps_envstr = cpp; /* remember location of envp for later */ for (; --envc >= 0; sp += len, dp += len) if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) return error; if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) return error; *stackp = (char *)cpp; return 0; } #ifdef LKM /* * Find an emulation of given name in list of emulations. * Needs to be called with the exec_lock held. */ const struct emul * emul_search(const char *name) { struct emul_entry *it; LIST_FOREACH(it, &el_head, el_list) { if (strcmp(name, it->el_emul->e_name) == 0) return it->el_emul; } return NULL; } /* * Add an emulation to list, if it's not there already. */ int emul_register(const struct emul *emul, int ro_entry) { struct emul_entry *ee; int error; error = 0; rw_enter(&exec_lock, RW_WRITER); if (emul_search(emul->e_name)) { error = EEXIST; goto out; } MALLOC(ee, struct emul_entry *, sizeof(struct emul_entry), M_EXEC, M_WAITOK); ee->el_emul = emul; ee->ro_entry = ro_entry; LIST_INSERT_HEAD(&el_head, ee, el_list); out: rw_exit(&exec_lock); return error; } /* * Remove emulation with name 'name' from list of supported emulations. */ int emul_unregister(const char *name) { const struct proclist_desc *pd; struct emul_entry *it; int i, error; struct proc *ptmp; error = 0; rw_enter(&exec_lock, RW_WRITER); LIST_FOREACH(it, &el_head, el_list) { if (strcmp(it->el_emul->e_name, name) == 0) break; } if (!it) { error = ENOENT; goto out; } if (it->ro_entry) { error = EBUSY; goto out; } /* test if any execw[] entry is still using this */ for(i=0; i < nexecs; i++) { if (execsw[i]->es_emul == it->el_emul) { error = EBUSY; goto out; } } /* * Test if any process is running under this emulation - since * emul_unregister() is running quite sendomly, it's better * to do expensive check here than to use any locking. */ mutex_enter(&proclist_lock); for (pd = proclists; pd->pd_list != NULL && !error; pd++) { PROCLIST_FOREACH(ptmp, pd->pd_list) { if (ptmp->p_emul == it->el_emul) { error = EBUSY; break; } } } mutex_exit(&proclist_lock); if (error) goto out; /* entry is not used, remove it */ LIST_REMOVE(it, el_list); FREE(it, M_EXEC); out: rw_exit(&exec_lock); return error; } /* * Add execsw[] entry. */ int exec_add(struct execsw *esp, const char *e_name) { struct exec_entry *it; int error; error = 0; rw_enter(&exec_lock, RW_WRITER); if (!esp->es_emul) { esp->es_emul = emul_search(e_name); if (!esp->es_emul) { error = ENOENT; goto out; } } LIST_FOREACH(it, &ex_head, ex_list) { /* assume tuple (makecmds, probe_func, emulation) is unique */ if (it->es->es_makecmds == esp->es_makecmds && it->es->u.elf_probe_func == esp->u.elf_probe_func && it->es->es_emul == esp->es_emul) { error = EEXIST; goto out; } } /* if we got here, the entry doesn't exist yet */ MALLOC(it, struct exec_entry *, sizeof(struct exec_entry), M_EXEC, M_WAITOK); it->es = esp; LIST_INSERT_HEAD(&ex_head, it, ex_list); /* update execsw[] */ exec_init(0); out: rw_exit(&exec_lock); return error; } /* * Remove execsw[] entry. */ int exec_remove(const struct execsw *esp) { struct exec_entry *it; int error; error = 0; rw_enter(&exec_lock, RW_WRITER); LIST_FOREACH(it, &ex_head, ex_list) { /* assume tuple (makecmds, probe_func, emulation) is unique */ if (it->es->es_makecmds == esp->es_makecmds && it->es->u.elf_probe_func == esp->u.elf_probe_func && it->es->es_emul == esp->es_emul) break; } if (!it) { error = ENOENT; goto out; } /* remove item from list and free resources */ LIST_REMOVE(it, ex_list); FREE(it, M_EXEC); /* update execsw[] */ exec_init(0); out: rw_exit(&exec_lock); return error; } static void link_es(struct execsw_entry **listp, const struct execsw *esp) { struct execsw_entry *et, *e1; et = (struct execsw_entry *) malloc(sizeof(struct execsw_entry), M_TEMP, M_WAITOK); et->next = NULL; et->es = esp; if (*listp == NULL) { *listp = et; return; } switch(et->es->es_prio) { case EXECSW_PRIO_FIRST: /* put new entry as the first */ et->next = *listp; *listp = et; break; case EXECSW_PRIO_ANY: /* put new entry after all *_FIRST and *_ANY entries */ for(e1 = *listp; e1->next && e1->next->es->es_prio != EXECSW_PRIO_LAST; e1 = e1->next); et->next = e1->next; e1->next = et; break; case EXECSW_PRIO_LAST: /* put new entry as the last one */ for(e1 = *listp; e1->next; e1 = e1->next); e1->next = et; break; default: #ifdef DIAGNOSTIC panic("execw[] entry with unknown priority %d found", et->es->es_prio); #else free(et, M_TEMP); #endif break; } } /* * Initialize exec structures. If init_boot is true, also does necessary * one-time initialization (it's called from main() that way). * Once system is multiuser, this should be called with exec_lock held, * i.e. via exec_{add|remove}(). */ int exec_init(int init_boot) { const struct execsw **new_es, * const *old_es; struct execsw_entry *list, *e1; struct exec_entry *e2; int i, es_sz; if (init_boot) { /* do one-time initializations */ rw_init(&exec_lock); /* register compiled-in emulations */ for(i=0; i < nexecs_builtin; i++) { if (execsw_builtin[i].es_emul) emul_register(execsw_builtin[i].es_emul, 1); } #ifdef DIAGNOSTIC if (i == 0) panic("no emulations found in execsw_builtin[]"); #endif } /* * Build execsw[] array from builtin entries and entries added * at runtime. */ list = NULL; for(i=0; i < nexecs_builtin; i++) link_es(&list, &execsw_builtin[i]); /* Add dynamically loaded entries */ es_sz = nexecs_builtin; LIST_FOREACH(e2, &ex_head, ex_list) { link_es(&list, e2->es); es_sz++; } /* * Now that we have sorted all execw entries, create new execsw[] * and free no longer needed memory in the process. */ new_es = malloc(es_sz * sizeof(struct execsw *), M_EXEC, M_WAITOK); for(i=0; list; i++) { new_es[i] = list->es; e1 = list->next; free(list, M_TEMP); list = e1; } /* * New execsw[] array built, now replace old execsw[] and free * used memory. */ old_es = execsw; execsw = new_es; nexecs = es_sz; if (old_es) /*XXXUNCONST*/ free(__UNCONST(old_es), M_EXEC); /* * Figure out the maximum size of an exec header. */ exec_maxhdrsz = 0; for (i = 0; i < nexecs; i++) { if (execsw[i]->es_hdrsz > exec_maxhdrsz) exec_maxhdrsz = execsw[i]->es_hdrsz; } return 0; } #endif #ifndef LKM /* * Simplified exec_init() for kernels without LKMs. Only initialize * exec_maxhdrsz and execsw[]. */ int exec_init(int init_boot) { int i; #ifdef DIAGNOSTIC if (!init_boot) panic("exec_init(): called with init_boot == 0"); #endif /* do one-time initializations */ nexecs = nexecs_builtin; execsw = malloc(nexecs*sizeof(struct execsw *), M_EXEC, M_WAITOK); /* * Fill in execsw[] and figure out the maximum size of an exec header. */ exec_maxhdrsz = 0; for(i=0; i < nexecs; i++) { execsw[i] = &execsw_builtin[i]; if (execsw_builtin[i].es_hdrsz > exec_maxhdrsz) exec_maxhdrsz = execsw_builtin[i].es_hdrsz; } return 0; } #endif /* !LKM */ static int exec_sigcode_map(struct proc *p, const struct emul *e) { vaddr_t va; vsize_t sz; int error; struct uvm_object *uobj; sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; if (e->e_sigobject == NULL || sz == 0) { return 0; } /* * If we don't have a sigobject for this emulation, create one. * * sigobject is an anonymous memory object (just like SYSV shared * memory) that we keep a permanent reference to and that we map * in all processes that need this sigcode. The creation is simple, * we create an object, add a permanent reference to it, map it in * kernel space, copy out the sigcode to it and unmap it. * We map it with PROT_READ|PROT_EXEC into the process just * the way sys_mmap() would map it. */ uobj = *e->e_sigobject; if (uobj == NULL) { uobj = uao_create(sz, 0); (*uobj->pgops->pgo_reference)(uobj); va = vm_map_min(kernel_map); if ((error = uvm_map(kernel_map, &va, round_page(sz), uobj, 0, 0, UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) { printf("kernel mapping failed %d\n", error); (*uobj->pgops->pgo_detach)(uobj); return (error); } memcpy((void *)va, e->e_sigcode, sz); #ifdef PMAP_NEED_PROCWR pmap_procwr(&proc0, va, sz); #endif uvm_unmap(kernel_map, va, va + round_page(sz)); *e->e_sigobject = uobj; } /* Just a hint to uvm_map where to put it. */ va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, round_page(sz)); #ifdef __alpha__ /* * Tru64 puts /sbin/loader at the end of user virtual memory, * which causes the above calculation to put the sigcode at * an invalid address. Put it just below the text instead. */ if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) { va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz); } #endif (*uobj->pgops->pgo_reference)(uobj); error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz), uobj, 0, 0, UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); if (error) { (*uobj->pgops->pgo_detach)(uobj); return (error); } p->p_sigctx.ps_sigcode = (void *)va; return (0); }