Exemple #1
0
/*
 * Dump core, into a file named "progname.core" or "core" (depending on the
 * value of shortcorename), unless the process was setuid/setgid.
 */
static int
coredump(struct lwp *l, const char *pattern)
{
	struct vnode		*vp;
	struct proc		*p;
	struct vmspace		*vm;
	kauth_cred_t		cred;
	struct pathbuf		*pb;
	struct nameidata	nd;
	struct vattr		vattr;
	struct coredump_iostate	io;
	struct plimit		*lim;
	int			error, error1;
	char			*name, *lastslash;

	name = PNBUF_GET();

	p = l->l_proc;
	vm = p->p_vmspace;

	mutex_enter(proc_lock);		/* p_session */
	mutex_enter(p->p_lock);

	/*
	 * Refuse to core if the data + stack + user size is larger than
	 * the core dump limit.  XXX THIS IS WRONG, because of mapped
	 * data.
	 */
	if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >=
	    p->p_rlimit[RLIMIT_CORE].rlim_cur) {
		error = EFBIG;		/* better error code? */
		mutex_exit(p->p_lock);
		mutex_exit(proc_lock);
		goto done;
	}

	/*
	 * It may well not be curproc, so grab a reference to its current
	 * credentials.
	 */
	kauth_cred_hold(p->p_cred);
	cred = p->p_cred;

	/*
	 * Make sure the process has not set-id, to prevent data leaks,
	 * unless it was specifically requested to allow set-id coredumps.
	 */
	if (p->p_flag & PK_SUGID) {
		if (!security_setidcore_dump) {
			error = EPERM;
			mutex_exit(p->p_lock);
			mutex_exit(proc_lock);
			goto done;
		}
		pattern = security_setidcore_path;
	}

	/* Lock, as p_limit and pl_corename might change. */
	lim = p->p_limit;
	mutex_enter(&lim->pl_lock);
	if (pattern == NULL) {
		pattern = lim->pl_corename;
	}
	error = coredump_buildname(p, name, pattern, MAXPATHLEN);
	mutex_exit(&lim->pl_lock);

	if (error) {
		mutex_exit(p->p_lock);
		mutex_exit(proc_lock);
		goto done;
	}

	/*
	 * On a simple filename, see if the filesystem allow us to write
	 * core dumps there.
	 */
	lastslash = strrchr(name, '/');
	if (!lastslash) {
		vp = p->p_cwdi->cwdi_cdir;
		if (vp->v_mount == NULL ||
		    (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
			error = EPERM;
	}

	mutex_exit(p->p_lock);
	mutex_exit(proc_lock);
	if (error)
		goto done;

	/*
	 * On a complex filename, see if the filesystem allow us to write
	 * core dumps there.
	 *
	 * XXX: We should have an API that avoids double lookups
	 */
	if (lastslash) {
		char c[2];

		if (lastslash - name >= MAXPATHLEN - 2) {
			error = EPERM;
			goto done;
		}

		c[0] = lastslash[1];
		c[1] = lastslash[2];
		lastslash[1] = '.';
		lastslash[2] = '\0';
		error = namei_simple_kernel(name, NSM_FOLLOW_NOEMULROOT, &vp);
		if (error)
			goto done;
		if (vp->v_mount == NULL ||
		    (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
			error = EPERM;
		vrele(vp);
		if (error)
			goto done;
		lastslash[1] = c[0];
		lastslash[2] = c[1];
	}

	pb = pathbuf_create(name);
	if (pb == NULL) {
		error = ENOMEM;
		goto done;
	}
	NDINIT(&nd, LOOKUP, NOFOLLOW, pb);
	if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE,
	    S_IRUSR | S_IWUSR)) != 0) {
		pathbuf_destroy(pb);
		goto done;
	}
	vp = nd.ni_vp;
	pathbuf_destroy(pb);

	/*
	 * Don't dump to:
	 * 	- non-regular files
	 * 	- files with links
	 * 	- files we don't own
	 */
	if (vp->v_type != VREG ||
	    VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1 ||
	    vattr.va_uid != kauth_cred_geteuid(cred)) {
		error = EACCES;
		goto out;
	}
	vattr_null(&vattr);
	vattr.va_size = 0;

	if ((p->p_flag & PK_SUGID) && security_setidcore_dump) {
		vattr.va_uid = security_setidcore_owner;
		vattr.va_gid = security_setidcore_group;
		vattr.va_mode = security_setidcore_mode;
	}

	VOP_SETATTR(vp, &vattr, cred);
	p->p_acflag |= ACORE;

	io.io_lwp = l;
	io.io_vp = vp;
	io.io_cred = cred;
	io.io_offset = 0;

	/* Now dump the actual core file. */
	error = (*p->p_execsw->es_coredump)(l, &io);
 out:
	VOP_UNLOCK(vp);
	error1 = vn_close(vp, FWRITE, cred);
	if (error == 0)
		error = error1;
done:
	if (name != NULL)
		PNBUF_PUT(name);
	return error;
}
Exemple #2
0
/*
 * Dump core, into a file named "progname.core" or "core" (depending on the
 * value of shortcorename), unless the process was setuid/setgid.
 */
int
coredump(struct lwp *l, const char *pattern)
{
	struct vnode		*vp;
	struct proc		*p;
	struct vmspace		*vm;
	kauth_cred_t		cred;
	struct nameidata	nd;
	struct vattr		vattr;
	struct coredump_iostate	io;
	struct plimit		*lim;
	int			error, error1;
	char			*name;

	name = PNBUF_GET();

	p = l->l_proc;
	vm = p->p_vmspace;

	mutex_enter(proc_lock);		/* p_session */
	mutex_enter(p->p_lock);

	/*
	 * Refuse to core if the data + stack + user size is larger than
	 * the core dump limit.  XXX THIS IS WRONG, because of mapped
	 * data.
	 */
	if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >=
	    p->p_rlimit[RLIMIT_CORE].rlim_cur) {
		error = EFBIG;		/* better error code? */
		mutex_exit(p->p_lock);
		mutex_exit(proc_lock);
		goto done;
	}

	/*
	 * It may well not be curproc, so grab a reference to its current
	 * credentials.
	 */
	kauth_cred_hold(p->p_cred);
	cred = p->p_cred;

	/*
	 * The core dump will go in the current working directory.  Make
	 * sure that the directory is still there and that the mount flags
	 * allow us to write core dumps there.
	 *
	 * XXX: this is partially bogus, it should be checking the directory
	 * into which the file is actually written - which probably needs
	 * a flag on namei()
	 */
	vp = p->p_cwdi->cwdi_cdir;
	if (vp->v_mount == NULL ||
	    (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) {
		error = EPERM;
		mutex_exit(p->p_lock);
		mutex_exit(proc_lock);
		goto done;
	}

	/*
	 * Make sure the process has not set-id, to prevent data leaks,
	 * unless it was specifically requested to allow set-id coredumps.
	 */
	if (p->p_flag & PK_SUGID) {
		if (!security_setidcore_dump) {
			error = EPERM;
			mutex_exit(p->p_lock);
			mutex_exit(proc_lock);
			goto done;
		}
		pattern = security_setidcore_path;
	}

	/* It is (just) possible for p_limit and pl_corename to change */
	lim = p->p_limit;
	mutex_enter(&lim->pl_lock);
	if (pattern == NULL)
		pattern = lim->pl_corename;
	error = coredump_buildname(p, name, pattern, MAXPATHLEN);
	mutex_exit(&lim->pl_lock);
	mutex_exit(p->p_lock);
	mutex_exit(proc_lock);
	if (error)
		goto done;
	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name);
	if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE,
	    S_IRUSR | S_IWUSR)) != 0)
		goto done;
	vp = nd.ni_vp;

	/* Don't dump to non-regular files or files with links. */
	if (vp->v_type != VREG ||
	    VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1) {
		error = EINVAL;
		goto out;
	}
	VATTR_NULL(&vattr);
	vattr.va_size = 0;

	if ((p->p_flag & PK_SUGID) && security_setidcore_dump) {
		vattr.va_uid = security_setidcore_owner;
		vattr.va_gid = security_setidcore_group;
		vattr.va_mode = security_setidcore_mode;
	}

	VOP_SETATTR(vp, &vattr, cred);
	p->p_acflag |= ACORE;

	io.io_lwp = l;
	io.io_vp = vp;
	io.io_cred = cred;
	io.io_offset = 0;

	/* Now dump the actual core file. */
	error = (*p->p_execsw->es_coredump)(l, &io);
 out:
	VOP_UNLOCK(vp, 0);
	error1 = vn_close(vp, FWRITE, cred);
	if (error == 0)
		error = error1;
done:
	if (name != NULL)
		PNBUF_PUT(name);
	return error;
}