From: Jeff Layton Date: Thu, 8 Nov 2012 20:00:04 +0000 (-0500) Subject: nfsdcltrack: add a new "one-shot" program for manipulating the client tracking db X-Git-Tag: debian/1%1.2.8-1~11^2^2~64 X-Git-Url: https://git.decadent.org.uk/gitweb/?a=commitdiff_plain;h=09cc3c831c8b1f27439fe09c951139bb6ec8e6c6;p=nfs-utils.git nfsdcltrack: add a new "one-shot" program for manipulating the client tracking db Usermode helper upcalls are all the rage these days for infrequent upcalls, since they make it rather idiot-proof. No running daemon is required, so there's really no setup beyond ensuring that the callout exists and is runnable. This program adds a callout program to nfs-utils for that purpose. The storage engine on the backend is identical to the one used by nfsdcld. This just adds a new frontend for it. For now, building with --enable-nfsdcltrack gives you both nfsdcld and nfsdcltrack programs. A later patch will remove nfsdcld altogether. Signed-off-by: Jeff Layton Signed-off-by: Steve Dickson --- diff --git a/.gitignore b/.gitignore index 96f9750..39853d9 100644 --- a/.gitignore +++ b/.gitignore @@ -49,7 +49,7 @@ utils/rquotad/rquotad utils/rquotad/rquota.h utils/rquotad/rquota_xdr.c utils/showmount/showmount -utils/nfsdcld/nfsdcld +utils/nfsdcltrack/nfsdcltrack utils/statd/statd tools/locktest/testlk tools/getiversion/getiversion diff --git a/utils/nfsdcltrack/Makefile.am b/utils/nfsdcltrack/Makefile.am index 073a71b..afae455 100644 --- a/utils/nfsdcltrack/Makefile.am +++ b/utils/nfsdcltrack/Makefile.am @@ -4,11 +4,13 @@ man8_MANS = nfsdcld.man EXTRA_DIST = $(man8_MANS) AM_CFLAGS += -D_LARGEFILE64_SOURCE -sbin_PROGRAMS = nfsdcld +sbin_PROGRAMS = nfsdcld nfsdcltrack nfsdcld_SOURCES = nfsdcld.c sqlite.c - nfsdcld_LDADD = ../../support/nfs/libnfs.a $(LIBEVENT) $(LIBSQLITE) $(LIBCAP) +nfsdcltrack_SOURCES = nfsdcltrack.c sqlite.c +nfsdcltrack_LDADD = ../../support/nfs/libnfs.a $(LIBSQLITE) $(LIBCAP) + MAINTAINERCLEANFILES = Makefile.in diff --git a/utils/nfsdcltrack/nfsdcld b/utils/nfsdcltrack/nfsdcld index 651b0c3..eedf29d 100755 Binary files a/utils/nfsdcltrack/nfsdcld and b/utils/nfsdcltrack/nfsdcld differ diff --git a/utils/nfsdcltrack/nfsdcltrack.c b/utils/nfsdcltrack/nfsdcltrack.c new file mode 100644 index 0000000..1d262a2 --- /dev/null +++ b/utils/nfsdcltrack/nfsdcltrack.c @@ -0,0 +1,436 @@ +/* + * nfsdcltrack.c -- NFSv4 client name tracking program + * + * Copyright (C) 2012 Jeff Layton + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif /* HAVE_CONFIG_H */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef HAVE_SYS_CAPABILITY_H +#include +#include +#endif + +#include "xlog.h" +#include "sqlite.h" + +#ifndef CLD_DEFAULT_STORAGEDIR +#define CLD_DEFAULT_STORAGEDIR NFS_STATEDIR "/nfsdcltrack" +#endif + +/* defined by RFC 3530 */ +#define NFS4_OPAQUE_LIMIT 1024 + +/* private data structures */ +struct cltrack_cmd { + char *name; + bool needs_arg; + int (*func)(const char *arg); +}; + +/* forward declarations */ +static int cltrack_init(const char *unused); +static int cltrack_create(const char *id); +static int cltrack_remove(const char *id); +static int cltrack_check(const char *id); +static int cltrack_gracedone(const char *gracetime); + +/* global variables */ +static struct option longopts[] = +{ + { "help", 0, NULL, 'h' }, + { "debug", 0, NULL, 'd' }, + { "foreground", 0, NULL, 'f' }, + { "storagedir", 1, NULL, 's' }, + { NULL, 0, 0, 0 }, +}; + +static struct cltrack_cmd commands[] = +{ + { "init", false, cltrack_init }, + { "create", true, cltrack_create }, + { "remove", true, cltrack_remove }, + { "check", true, cltrack_check }, + { "gracedone", true, cltrack_gracedone }, + { NULL, false, NULL }, +}; + +static char *storagedir = CLD_DEFAULT_STORAGEDIR; + +/* common buffer for holding id4 blobs */ +static unsigned char blob[NFS4_OPAQUE_LIMIT]; + +static void +usage(char *progname) +{ + printf("%s [ -hfd ] [ -s dir ] < cmd > < arg >\n", progname); + printf("Where < cmd > is one of the following and takes the following < arg >:\n"); + printf(" init\n"); + printf(" create \n"); + printf(" remove \n"); + printf(" check \n"); + printf(" gracedone \n"); +} + + +/** + * hex_to_bin - convert a hex digit to its real value + * @ch: ascii character represents hex digit + * + * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad + * input. + * + * Note: borrowed from lib/hexdump.c in the Linux kernel sources. + */ +static int +hex_to_bin(char ch) +{ + if ((ch >= '0') && (ch <= '9')) + return ch - '0'; + ch = tolower(ch); + if ((ch >= 'a') && (ch <= 'f')) + return ch - 'a' + 10; + return -1; +} + +/** + * hex_str_to_bin - convert a hexidecimal string into a binary blob + * + * @src: string of hex digit pairs + * @dst: destination buffer to hold binary data + * @dstsize: size of the destination buffer + * + * Walk a string of hex digit pairs and convert them into binary data. Returns + * the resulting length of the binary data or a negative error code. If the + * data will not fit in the buffer, it returns -ENOBUFS (but will likely have + * clobbered the dst buffer in the process of determining that). If there are + * non-hexidecimal characters in the src, or an odd number of them then it + * returns -EINVAL. + */ +static ssize_t +hex_str_to_bin(const char *src, unsigned char *dst, ssize_t dstsize) +{ + unsigned char *tmpdst = dst; + + while (*src) { + int hi, lo; + + /* make sure we don't overrun the dst buffer */ + if ((tmpdst - dst) >= dstsize) + return -ENOBUFS; + + hi = hex_to_bin(*src++); + + /* did we get an odd number of characters? */ + if (!*src) + return -EINVAL; + lo = hex_to_bin(*src++); + + /* one of the characters isn't a hex digit */ + if (hi < 0 || lo < 0) + return -EINVAL; + + /* now place it in the dst buffer */ + *tmpdst++ = (hi << 4) | lo; + } + + return (ssize_t)(tmpdst - dst); +} + +/* + * This program will almost always be run with root privileges since the + * kernel will call out to run it. Drop all capabilities prior to doing + * anything important to limit the exposure to potential compromise. + * + * FIXME: should we setuid to a different user early on instead? + */ +static int +cltrack_set_caps(void) +{ + int ret = 0; +#ifdef HAVE_SYS_CAPABILITY_H + unsigned long i; + cap_t caps; + + /* prune the bounding set to nothing */ + for (i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0 ; ++i) { + ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0); + if (ret) { + xlog(L_ERROR, "Unable to prune capability %lu from " + "bounding set: %m", i); + return -errno; + } + } + + /* get a blank capset */ + caps = cap_init(); + if (caps == NULL) { + xlog(L_ERROR, "Unable to get blank capability set: %m"); + return -errno; + } + + /* reset the process capabilities */ + if (cap_set_proc(caps) != 0) { + xlog(L_ERROR, "Unable to set process capabilities: %m"); + ret = -errno; + } + cap_free(caps); +#endif + return ret; +} + +static int +cltrack_init(const char __attribute__((unused)) *unused) +{ + int ret; + + /* + * see if the storagedir is writable by root w/o CAP_DAC_OVERRIDE. + * If it isn't then give the user a warning but proceed as if + * everything is OK. If the DB has already been created, then + * everything might still work. If it doesn't exist at all, then + * assume that the maindb init will be able to create it. Fail on + * anything else. + */ + if (access(storagedir, W_OK) == -1) { + switch (errno) { + case EACCES: + xlog(L_WARNING, "Storage directory %s is not writable. " + "Should be owned by root and writable " + "by owner!", storagedir); + break; + case ENOENT: + /* ignore and assume that we can create dir as root */ + break; + default: + xlog(L_ERROR, "Unexpected error when checking access " + "on %s: %m", storagedir); + return -errno; + } + } + + /* set up storage db */ + ret = sqlite_maindb_init(storagedir); + if (ret) { + xlog(L_ERROR, "Failed to init database: %d", ret); + /* + * Convert any error here into -EACCES. It's not truly + * accurate in all cases, but it should cause the kernel to + * stop upcalling until the problem is resolved. + */ + ret = -EACCES; + } + return ret; +} + +static int +cltrack_create(const char *id) +{ + int ret; + ssize_t len; + + xlog(D_GENERAL, "%s: create client record.", __func__); + + ret = sqlite_prepare_dbh(storagedir); + if (ret) + return ret; + + len = hex_str_to_bin(id, blob, sizeof(blob)); + if (len < 0) + return (int)len; + + ret = sqlite_insert_client(blob, len); + + return ret ? -EREMOTEIO : ret; +} + +static int +cltrack_remove(const char *id) +{ + int ret; + ssize_t len; + + xlog(D_GENERAL, "%s: remove client record.", __func__); + + ret = sqlite_prepare_dbh(storagedir); + if (ret) + return ret; + + len = hex_str_to_bin(id, blob, sizeof(blob)); + if (len < 0) + return (int)len; + + ret = sqlite_remove_client(blob, len); + + return ret ? -EREMOTEIO : ret; +} + +static int +cltrack_check(const char *id) +{ + int ret; + ssize_t len; + + xlog(D_GENERAL, "%s: check client record", __func__); + + ret = sqlite_prepare_dbh(storagedir); + if (ret) + return ret; + + len = hex_str_to_bin(id, blob, sizeof(blob)); + if (len < 0) + return (int)len; + + ret = sqlite_check_client(blob, len); + + return ret ? -EPERM : ret; +} + +static int +cltrack_gracedone(const char *timestr) +{ + int ret; + char *tail; + time_t gracetime; + + + ret = sqlite_prepare_dbh(storagedir); + if (ret) + return ret; + + errno = 0; + gracetime = strtol(timestr, &tail, 0); + + /* did the resulting value overflow? (Probably -ERANGE here) */ + if (errno) + return -errno; + + /* string wasn't fully converted */ + if (*tail) + return -EINVAL; + + xlog(D_GENERAL, "%s: grace done. gracetime=%ld", __func__, gracetime); + + ret = sqlite_remove_unreclaimed(gracetime); + + return ret ? -EREMOTEIO : ret; +} + +static struct cltrack_cmd * +find_cmd(char *cmdname) +{ + struct cltrack_cmd *current = &commands[0]; + + while (current->name) { + if (!strcmp(cmdname, current->name)) + return current; + ++current; + } + + xlog(L_ERROR, "%s: '%s' doesn't match any known command", + __func__, cmdname); + return NULL; +} + +int +main(int argc, char **argv) +{ + char arg; + int rc = 0; + char *progname, *cmdarg = NULL; + struct cltrack_cmd *cmd; + + progname = basename(argv[0]); + + xlog_syslog(1); + xlog_stderr(0); + + /* process command-line options */ + while ((arg = getopt_long(argc, argv, "hdfs:", longopts, + NULL)) != EOF) { + switch (arg) { + case 'd': + xlog_config(D_ALL, 1); + case 'f': + xlog_syslog(0); + xlog_stderr(1); + break; + case 's': + storagedir = optarg; + break; + default: + usage(progname); + return 0; + } + } + + xlog_open(progname); + + /* we expect a command, at least */ + if (optind >= argc) { + xlog(L_ERROR, "Missing command name\n"); + rc = -EINVAL; + goto out; + } + + /* drop all capabilities */ + rc = cltrack_set_caps(); + if (rc) + goto out; + + cmd = find_cmd(argv[optind]); + if (!cmd) { + /* + * In the event that we get a command that we don't understand + * then return a distinct error. The kernel can use this to + * determine a new kernel/old userspace situation and cope + * with it. + */ + rc = -ENOSYS; + goto out; + } + + /* populate arg var if command needs it */ + if (cmd->needs_arg) { + if (optind + 1 >= argc) { + xlog(L_ERROR, "Command %s requires an argument\n", + cmd->name); + rc = -EINVAL; + goto out; + } + cmdarg = argv[optind + 1]; + } + rc = cmd->func(cmdarg); +out: + return rc; +}