/src/sudo/plugins/sudoers/match_command.c

Source
/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 1996, 1998-2005, 2007-2023
 *  Todd C. Miller <Todd.Miller@sudo.ws>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <config.h>

#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef SUDOERS_NAME_MATCH
# ifdef HAVE_GLOB
#  include <glob.h>
# else
#  include <compat/glob.h>
# endif /* HAVE_GLOB */
#endif /* SUDOERS_NAME_MATCH */
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#ifdef HAVE_FNMATCH
# include <fnmatch.h>
#else
# include <compat/fnmatch.h>
#endif /* HAVE_FNMATCH */
#include <regex.h>

#include <sudoers.h>
#include <gram.h>

#if !defined(O_EXEC) && defined(O_PATH)
# define O_EXEC O_PATH
#endif

static int
regex_matches(const char *pattern, const char *str)
{
    const char *errstr;
    regex_t re;
    int ret;
    debug_decl(regex_matches, SUDOERS_DEBUG_MATCH);

    if (!sudo_regex_compile(&re, pattern, &errstr)) {
  sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
      "unable to compile regular expression \"%s\": %s",
      pattern, errstr);
  debug_return_int(DENY);
    }

    if (regexec(&re, str, 0, NULL, 0) == 0)
  ret = ALLOW;
    else
  ret = DENY;
    regfree(&re);

    debug_return_int(ret);
}

static int
command_args_match(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args)
{
    const char *args = ctx->user.cmnd_args ? ctx->user.cmnd_args : "";
    int flags = 0;
    debug_decl(command_args_match, SUDOERS_DEBUG_MATCH);

    /*
     * If no args specified in sudoers, any user args are allowed.
     * If the empty string is specified in sudoers, no user args are allowed.
     */
    if (sudoers_args == NULL)
  debug_return_int(ALLOW);
    if (strcmp("\"\"", sudoers_args) == 0)
  debug_return_int(ctx->user.cmnd_args ? DENY : ALLOW);

    /*
     * If args are specified in sudoers, they must match the user args.
     * Args are matched either as a regular expression or glob pattern.
     */
    if (sudoers_args[0] == '^') {
  size_t len = strlen(sudoers_args);
  if (len > 0 && sudoers_args[len - 1] == '$')
      debug_return_int(regex_matches(sudoers_args, args));
    }

    /* If running as sudoedit, all args are assumed to be paths. */
    if (strcmp(sudoers_cmnd, "sudoedit") == 0)
  flags = FNM_PATHNAME;
    if (fnmatch(sudoers_args, args, flags) == 0)
  debug_return_int(ALLOW);
    debug_return_int(DENY);
}

#ifndef SUDOERS_NAME_MATCH
/*
 * Stat file by fd is possible, else by path.
 * Returns true on success, else false.
 */
static bool
do_stat(int fd, const char *path, const char *runchroot, struct stat *sb)
{
    char pathbuf[PATH_MAX];
    bool ret;
    debug_decl(do_stat, SUDOERS_DEBUG_MATCH);

    if (fd != -1) {
  ret = fstat(fd, sb) == 0;
    } else {
  /* Make path relative to the new root, if any. */
  if (runchroot != NULL) {
      /* XXX - handle symlinks and '..' in path outside chroot */
      const int len =
    snprintf(pathbuf, sizeof(pathbuf), "%s%s", runchroot, path);
      if (len >= ssizeof(pathbuf)) {
    errno = ENAMETOOLONG;
    debug_return_bool(false);
      }
      path = pathbuf;
  }
  ret = stat(path, sb) == 0;
    }
    debug_return_bool(ret);
}
#endif /* SUDOERS_NAME_MATCH */

/*
 * Check whether the fd refers to a shell script with a "#!" shebang.
 */
static bool
is_script(int fd)
{
    bool ret = false;
    char magic[2];
    debug_decl(is_script, SUDOERS_DEBUG_MATCH);

    if (pread(fd, magic, 2, 0) == 2) {
  if (magic[0] == '#' && magic[1] == '!')
      ret = true;
    }
    debug_return_bool(ret);
}

/*
 * Open path if fdexec is enabled or if a digest is present.
 * Returns false on error, else true.
 */
static bool
open_cmnd(const char *path, const char *runchroot,
    const struct command_digest_list *digests, int *fdp)
{
    int fd;
    char pathbuf[PATH_MAX];
    debug_decl(open_cmnd, SUDOERS_DEBUG_MATCH);

    /* Only open the file for fdexec or for digest matching. */
    if (def_fdexec != always && TAILQ_EMPTY(digests))
  debug_return_bool(true);

    /* Make path relative to the new root, if any. */
    if (runchroot != NULL) {
  /* XXX - handle symlinks and '..' in path outside chroot */
  const int len =
      snprintf(pathbuf, sizeof(pathbuf), "%s%s", runchroot, path);
  if (len >= ssizeof(pathbuf)) {
      errno = ENAMETOOLONG;
      debug_return_bool(false);
  }
  path = pathbuf;
    }

    fd = open(path, O_RDONLY|O_NONBLOCK);
# ifdef O_EXEC
    if (fd == -1 && errno == EACCES && TAILQ_EMPTY(digests)) {
  /* Try again with O_EXEC if no digest is specified. */
  const int saved_errno = errno;
  if ((fd = open(path, O_EXEC)) == -1)
      errno = saved_errno;
    }
# endif
    if (fd == -1)
  debug_return_bool(false);

    (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
    *fdp = fd;
    debug_return_bool(true);
}

static void
set_cmnd_fd(struct sudoers_context *ctx, int fd)
{
    debug_decl(set_cmnd_fd, SUDOERS_DEBUG_MATCH);

    if (ctx->runas.execfd != -1)
  close(ctx->runas.execfd);

    if (fd != -1) {
  if (def_fdexec == never) {
      /* Never use fexedcve() */
      close(fd);
      fd = -1;
  } else if (is_script(fd)) {
      char fdpath[PATH_MAX];
      struct stat sb;
      int flags;

      /* We can only use fexecve() on a script if /dev/fd/N exists. */
      (void)snprintf(fdpath, sizeof(fdpath), "/dev/fd/%d", fd);
      if (stat(fdpath, &sb) != 0) {
    /* Missing /dev/fd file, can't use fexecve(). */
    close(fd);
    fd = -1;
      } else {
    /*
     * Shell scripts go through namei twice so we can't have the
     * close on exec flag set on the fd for fexecve(2).
     */
    flags = fcntl(fd, F_GETFD) & ~FD_CLOEXEC;
    (void)fcntl(fd, F_SETFD, flags);
      }
  }
    }

    ctx->runas.execfd = fd;

    debug_return;
}

#ifndef SUDOERS_NAME_MATCH
/*
 * Return true if ctx->user.cmnd names one of the inodes in dir, else false.
 */
static int
command_matches_dir(struct sudoers_context *ctx, const char *sudoers_dir,
    size_t dlen, const char *runchroot,
    const struct command_digest_list *digests)
{
    struct stat sudoers_stat;
    char path[PATH_MAX], sdbuf[PATH_MAX];
    size_t chrootlen = 0;
    int len, fd = -1;
    int ret = DENY;
    debug_decl(command_matches_dir, SUDOERS_DEBUG_MATCH);

    /* Make sudoers_dir relative to the new root, if any. */
    if (runchroot != NULL) {
  /* XXX - handle symlinks and '..' in path outside chroot */
  len = snprintf(sdbuf, sizeof(sdbuf), "%s%s", runchroot, sudoers_dir);
  if (len >= ssizeof(sdbuf)) {
      errno = ENAMETOOLONG;
      sudo_warn("%s%s", runchroot, sudoers_dir);
      goto done;
  }
  sudoers_dir = sdbuf;
  chrootlen = strlen(runchroot);
    }

    /* Compare the canonicalized directories, if possible. */
    if (ctx->user.cmnd_dir != NULL) {
  char *resolved = canon_path(sudoers_dir);
  if (resolved != NULL) {
      if (strcmp(resolved, ctx->user.cmnd_dir) != 0) {
    canon_path_free(resolved);
    goto done;
      }
      canon_path_free(resolved);
  }
    }

    /* Check for command in sudoers_dir. */
    len = snprintf(path, sizeof(path), "%s/%s", sudoers_dir, ctx->user.cmnd_base);
    if (len < 0 || len >= ssizeof(path))
  goto done;

    /* Open the file for fdexec or for digest matching. */
    if (!open_cmnd(path, NULL, digests, &fd))
  goto done;
    if (!do_stat(fd, path, NULL, &sudoers_stat))
  goto done;

    if (ctx->user.cmnd_stat == NULL ||
  (ctx->user.cmnd_stat->st_dev == sudoers_stat.st_dev &&
  ctx->user.cmnd_stat->st_ino == sudoers_stat.st_ino)) {
  /* path is already relative to runchroot */
  if (digest_matches(fd, path, NULL, digests) != ALLOW)
      goto done;
  free(ctx->runas.cmnd);
  if ((ctx->runas.cmnd = strdup(path + chrootlen)) == NULL) {
      sudo_warnx(U_("%s: %s"), __func__,
    U_("unable to allocate memory"));
  }
  ret = ALLOW;
  goto done;
    }
    ret = DENY;

done:
    if (fd != -1)
  close(fd);
    debug_return_int(ret);
}
#else /* SUDOERS_NAME_MATCH */
/*
 * Return true if ctx->user.cmnd names one of the inodes in dir, else false.
 */
static int
command_matches_dir(struct sudoers_context *ctx, const char *sudoers_dir,
    size_t dlen, const char *runchroot,
    const struct command_digest_list *digests)
{
    int fd = -1;
    debug_decl(command_matches_dir, SUDOERS_DEBUG_MATCH);

    /* Match ctx->user.cmnd against sudoers_dir. */
    if (strncmp(ctx->user.cmnd, sudoers_dir, dlen) != 0 || ctx->user.cmnd[dlen] != '/')
  goto bad;

    /* Make sure ctx->user.cmnd is not in a subdir of sudoers_dir. */
    if (strchr(ctx->user.cmnd + dlen + 1, '\0') != NULL)
  goto bad;

    /* Open the file for fdexec or for digest matching. */
    if (!open_cmnd(ctx->user.cmnd, runchroot, digests, &fd))
  goto bad;
    if (digest_matches(fd, ctx->user.cmnd, runchroot, digests) != ALLOW)
  goto bad;
    set_cmnd_fd(ctx, fd);

    debug_return_int(ALLOW);
bad:
    if (fd != -1)
  close(fd);
    debug_return_int(DENY);
}
#endif /* SUDOERS_NAME_MATCH */

static int
command_matches_all(struct sudoers_context *ctx, const char *runchroot,
    const struct command_digest_list *digests)
{
#ifndef SUDOERS_NAME_MATCH
    struct stat sb;
#endif
    int fd = -1;
    debug_decl(command_matches_all, SUDOERS_DEBUG_MATCH);

    if (strchr(ctx->user.cmnd, '/') != NULL) {
#ifndef SUDOERS_NAME_MATCH
  /* Open the file for fdexec or for digest matching. */
  bool open_error = !open_cmnd(ctx->user.cmnd, runchroot, digests, &fd);

  /* A non-existent file is not an error for "sudo ALL". */
  if (do_stat(fd, ctx->user.cmnd, runchroot, &sb)) {
      if (open_error) {
    /* File exists but we couldn't open it above? */
    goto bad;
      }
  }
#else
  /* Open the file for fdexec or for digest matching. */
  (void)open_cmnd(ctx->user.cmnd, runchroot, digests, &fd);
#endif
    }

    /* Check digest of ctx->user.cmnd since we have no sudoers_cmnd for ALL. */
    if (digest_matches(fd, ctx->user.cmnd, runchroot, digests) != ALLOW)
  goto bad;
    set_cmnd_fd(ctx, fd);

    /* No need to set ctx->runas.cmnd for ALL. */
    debug_return_int(ALLOW);
bad:
    if (fd != -1)
  close(fd);
    debug_return_int(DENY);
}

static int
command_matches_fnmatch(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    const char *cmnd = ctx->user.cmnd;
    char buf[PATH_MAX];
    int len, fd = -1;
#ifndef SUDOERS_NAME_MATCH
    struct stat sb;
#endif
    debug_decl(command_matches_fnmatch, SUDOERS_DEBUG_MATCH);

    /*
     * Return ALLOW if fnmatch(3) succeeds AND
     *  a) there are no args in sudoers OR
     *  b) there are no args on command line and none required by sudoers OR
     *  c) there are args in sudoers and on command line and they match
     *     else return DENY.
     *
     * Neither sudoers_cmnd nor user_cmnd are relative to runchroot.
     * We do not attempt to match a relative path unless there is a
     * canonicalized version.
     */
    if (cmnd[0] != '/' || fnmatch(sudoers_cmnd, cmnd, FNM_PATHNAME) != 0) {
  /* No match, retry using the canonicalized path (if possible). */
  if (ctx->user.cmnd_dir == NULL)
      debug_return_int(DENY);
  len = snprintf(buf, sizeof(buf), "%s/%s", ctx->user.cmnd_dir,
      ctx->user.cmnd_base);
  if (len < 0 || len >= ssizeof(buf))
      debug_return_int(DENY);
  cmnd = buf;
  if (fnmatch(sudoers_cmnd, cmnd, FNM_PATHNAME) != 0)
      debug_return_int(DENY);
    }

    if (command_args_match(ctx, sudoers_cmnd, sudoers_args) == ALLOW) {
  /* Open the file for fdexec or for digest matching. */
  if (!open_cmnd(cmnd, runchroot, digests, &fd))
      goto bad;
#ifndef SUDOERS_NAME_MATCH
  if (!do_stat(fd, cmnd, runchroot, &sb))
      goto bad;
#endif
  /* Check digest of cmnd since sudoers_cmnd is a pattern. */
  if (digest_matches(fd, cmnd, runchroot, digests) != ALLOW)
      goto bad;
  set_cmnd_fd(ctx, fd);

  /* No need to set ctx->runas.cmnd since cmnd matches sudoers_cmnd */
  debug_return_int(ALLOW);
bad:
  if (fd != -1)
      close(fd);
    }
    debug_return_int(DENY);
}

static int
command_matches_regex(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    const char *cmnd = ctx->user.cmnd;
    char buf[PATH_MAX];
    int len, fd = -1;
#ifndef SUDOERS_NAME_MATCH
    struct stat sb;
#endif
    debug_decl(command_matches_regex, SUDOERS_DEBUG_MATCH);

    /*
     * Return ALLOW if sudoers_cmnd regex matches cmnd AND
     *  a) there are no args in sudoers OR
     *  b) there are no args on command line and none required by sudoers OR
     *  c) there are args in sudoers and on command line and they match
     *     else return DENY.
     *
     * Neither sudoers_cmnd nor user_cmnd are relative to runchroot.
     */
    if (cmnd[0] != '/' || regex_matches(sudoers_cmnd, cmnd) != ALLOW) {
  /* No match, retry using the canonicalized path (if possible). */
  if (ctx->user.cmnd_dir == NULL)
      debug_return_int(DENY);
  len = snprintf(buf, sizeof(buf), "%s/%s", ctx->user.cmnd_dir,
      ctx->user.cmnd_base);
  if (len < 0 || len >= ssizeof(buf))
      debug_return_int(DENY);
  cmnd = buf;
  if (regex_matches(sudoers_cmnd, cmnd) != ALLOW)
      debug_return_int(DENY);
    }

    if (command_args_match(ctx, sudoers_cmnd, sudoers_args) == ALLOW) {
  /* Open the file for fdexec or for digest matching. */
  if (!open_cmnd(cmnd, runchroot, digests, &fd))
      goto bad;
#ifndef SUDOERS_NAME_MATCH
  if (!do_stat(fd, cmnd, runchroot, &sb))
      goto bad;
#endif
  /* Check digest of cmnd since sudoers_cmnd is a pattern. */
  if (digest_matches(fd, cmnd, runchroot, digests) != ALLOW)
      goto bad;
  set_cmnd_fd(ctx, fd);

  /* No need to set ctx->runas.cmnd since cmnd matches sudoers_cmnd */
  debug_return_int(ALLOW);
bad:
  if (fd != -1)
      close(fd);
    }
    debug_return_int(DENY);
}

#ifndef SUDOERS_NAME_MATCH
static int
command_matches_glob(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    struct stat sudoers_stat;
    bool bad_digest = false;
    char **ap, *base, *cp;
    char pathbuf[PATH_MAX];
    int fd = -1;
    size_t dlen, chrootlen = 0;
    glob_t gl;
    debug_decl(command_matches_glob, SUDOERS_DEBUG_MATCH);

    /* Make sudoers_cmnd relative to the new root, if any. */
    if (runchroot != NULL) {
  /* XXX - handle symlinks and '..' in path outside chroot */
  const int len =
      snprintf(pathbuf, sizeof(pathbuf), "%s%s", runchroot, sudoers_cmnd);
  if (len >= ssizeof(pathbuf)) {
      errno = ENAMETOOLONG;
      sudo_warn("%s%s", runchroot, sudoers_cmnd);
      debug_return_int(DENY);
  }
  sudoers_cmnd = pathbuf;
  chrootlen = strlen(runchroot);
    }

    /*
     * First check to see if we can avoid the call to glob(3).
     * Short circuit if there are no meta chars in the command itself
     * and ctx->user.cmnd_base and basename(sudoers_cmnd) don't match.
     */
    dlen = strlen(sudoers_cmnd);
    if (sudoers_cmnd[dlen - 1] != '/') {
  base = sudo_basename(sudoers_cmnd);
  if (!has_meta(base) && strcmp(ctx->user.cmnd_base, base) != 0)
      debug_return_int(DENY);
    }

    /*
     * Return ALLOW if we find a match in the glob(3) results AND
     *  a) there are no args in sudoers OR
     *  b) there are no args on command line and none required by sudoers OR
     *  c) there are args in sudoers and on command line and they match
     * else return DENY.
     */
    if (glob(sudoers_cmnd, GLOB_NOSORT, NULL, &gl) != 0 || gl.gl_pathc == 0) {
  globfree(&gl);
  debug_return_int(DENY);
    }

    /* If ctx->user.cmnd is fully-qualified, check for an exact match. */
    if (ctx->user.cmnd[0] == '/') {
  for (ap = gl.gl_pathv; (cp = *ap) != NULL; ap++) {
      if (fd != -1) {
    close(fd);
    fd = -1;
      }
      /* Remove the runchroot, if any. */
      cp += chrootlen;

      if (strcmp(cp, ctx->user.cmnd) != 0)
    continue;
      /* Open the file for fdexec or for digest matching. */
      if (!open_cmnd(cp, runchroot, digests, &fd))
    continue;
      if (!do_stat(fd, cp, runchroot, &sudoers_stat))
    continue;
      if (ctx->user.cmnd_stat == NULL ||
    (ctx->user.cmnd_stat->st_dev == sudoers_stat.st_dev &&
    ctx->user.cmnd_stat->st_ino == sudoers_stat.st_ino)) {
    /* There could be multiple matches, check digest early. */
    if (digest_matches(fd, cp, runchroot, digests) != ALLOW) {
        bad_digest = true;
        continue;
    }
    free(ctx->runas.cmnd);
    if ((ctx->runas.cmnd = strdup(cp)) == NULL) {
        sudo_warnx(U_("%s: %s"), __func__,
      U_("unable to allocate memory"));
        cp = NULL;    /* fail closed */
    }
      } else {
    /* Paths match, but st_dev and st_ino are different. */
    cp = NULL;    /* fail closed */
      }
      goto done;
  }
    }
    /* No exact match, compare basename, cmnd_dir, st_dev and st_ino. */
    if (!bad_digest) {
  for (ap = gl.gl_pathv; (cp = *ap) != NULL; ap++) {
      if (fd != -1) {
    close(fd);
    fd = -1;
      }
      /* Remove the runchroot, if any. */
      cp += chrootlen;

      /* If it ends in '/' it is a directory spec. */
      dlen = strlen(cp);
      if (cp[dlen - 1] == '/') {
    if (command_matches_dir(ctx, cp, dlen, runchroot, digests) == ALLOW) {
        globfree(&gl);
        debug_return_int(ALLOW);
    }
    continue;
      }

      /* Only proceed if ctx->user.cmnd_base and basename(cp) match */
      base = sudo_basename(cp);
      if (strcmp(ctx->user.cmnd_base, base) != 0)
    continue;

      /* Compare the canonicalized parent directories, if possible. */
      if (ctx->user.cmnd_dir != NULL) {
    char *slash = strrchr(cp, '/');
    if (slash != NULL) {
        char *resolved;
        *slash = '\0';
        resolved = canon_path(cp);
        *slash = '/';
        if (resolved != NULL) {
      /* Canonicalized directories must match. */
      int result = strcmp(resolved, ctx->user.cmnd_dir);
      canon_path_free(resolved);
      if (result != 0)
          continue;
        }
    }
      }

      /* Open the file for fdexec or for digest matching. */
      if (!open_cmnd(cp, runchroot, digests, &fd))
    continue;
      if (!do_stat(fd, cp, runchroot, &sudoers_stat))
    continue;
      if (ctx->user.cmnd_stat == NULL ||
    (ctx->user.cmnd_stat->st_dev == sudoers_stat.st_dev &&
    ctx->user.cmnd_stat->st_ino == sudoers_stat.st_ino)) {
    if (digest_matches(fd, cp, runchroot, digests) != ALLOW)
        continue;
    free(ctx->runas.cmnd);
    if ((ctx->runas.cmnd = strdup(cp)) == NULL) {
        sudo_warnx(U_("%s: %s"), __func__,
      U_("unable to allocate memory"));
        cp = NULL;    /* fail closed */
    }
    goto done;
      }
  }
    }
done:
    globfree(&gl);
    if (cp != NULL) {
  if (command_args_match(ctx, sudoers_cmnd, sudoers_args) == ALLOW) {
      /* ctx->runas.cmnd was set above. */
      set_cmnd_fd(ctx, fd);
      debug_return_int(ALLOW);
  }
    }
    if (fd != -1)
  close(fd);
    debug_return_int(DENY);
}

static int
command_matches_normal(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    struct stat sudoers_stat;
    const char *base;
    size_t dlen;
    int fd = -1;
    debug_decl(command_matches_normal, SUDOERS_DEBUG_MATCH);

    /* If it ends in '/' it is a directory spec. */
    dlen = strlen(sudoers_cmnd);
    if (sudoers_cmnd[dlen - 1] == '/') {
  debug_return_int(command_matches_dir(ctx, sudoers_cmnd, dlen,
      runchroot, digests));
    }

    /* Only proceed if ctx->user.cmnd_base and basename(sudoers_cmnd) match */
    base = sudo_basename(sudoers_cmnd);
    if (strcmp(ctx->user.cmnd_base, base) != 0)
  debug_return_int(DENY);

    /* Compare the canonicalized parent directories, if possible. */
    if (ctx->user.cmnd_dir != NULL) {
  const char *slash = strrchr(sudoers_cmnd, '/');
  if (slash != NULL) {
      char sudoers_cmnd_dir[PATH_MAX], *resolved;
      const size_t len = (size_t)(slash - sudoers_cmnd);
      if (len >= sizeof(sudoers_cmnd_dir))
    goto bad;
      if (len != 0)
    memcpy(sudoers_cmnd_dir, sudoers_cmnd, len);
      sudoers_cmnd_dir[len] = '\0';
      resolved = canon_path(sudoers_cmnd_dir);
      if (resolved != NULL) {
    if (strcmp(resolved, ctx->user.cmnd_dir) != 0) {
        canon_path_free(resolved);
        goto bad;
    }
    canon_path_free(resolved);
      }
  }
    }

    /* Open the file for fdexec or for digest matching. */
    if (!open_cmnd(sudoers_cmnd, runchroot, digests, &fd))
  goto bad;

    /*
     * Return true if command matches AND
     *  a) there are no args in sudoers OR
     *  b) there are no args on command line and none req by sudoers OR
     *  c) there are args in sudoers and on command line and they match
     *  d) there is a digest and it matches
     */
    if (ctx->user.cmnd_stat != NULL && do_stat(fd, sudoers_cmnd, runchroot, &sudoers_stat)) {
  if (ctx->user.cmnd_stat->st_dev != sudoers_stat.st_dev ||
      ctx->user.cmnd_stat->st_ino != sudoers_stat.st_ino)
      goto bad;
    } else {
  /* Either user or sudoers command does not exist, match by name. */
  if (strcmp(ctx->user.cmnd, sudoers_cmnd) != 0)
      goto bad;
    }
    if (command_args_match(ctx, sudoers_cmnd, sudoers_args) != ALLOW)
  goto bad;
    if (digest_matches(fd, sudoers_cmnd, runchroot, digests) != ALLOW) {
  /* XXX - log functions not available but we should log very loudly */
  goto bad;
    }
    free(ctx->runas.cmnd);
    if ((ctx->runas.cmnd = strdup(sudoers_cmnd)) == NULL) {
  sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
  goto bad;
    }
    set_cmnd_fd(ctx, fd);
    debug_return_int(ALLOW);
bad:
    if (fd != -1)
  close(fd);
    debug_return_int(DENY);
}
#else /* SUDOERS_NAME_MATCH */
static int
command_matches_glob(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    return command_matches_fnmatch(ctx, sudoers_cmnd, sudoers_args, runchroot,
  digests);
}

static int
command_matches_normal(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot,
    const struct command_digest_list *digests)
{
    size_t dlen;
    int fd = -1;
    debug_decl(command_matches_normal, SUDOERS_DEBUG_MATCH);

    /* If it ends in '/' it is a directory spec. */
    dlen = strlen(sudoers_cmnd);
    if (sudoers_cmnd[dlen - 1] == '/') {
  debug_return_int(command_matches_dir(ctx, sudoers_cmnd, dlen, runchroot,
      digests));
    }

    if (strcmp(ctx->user.cmnd, sudoers_cmnd) == 0) {
  if (command_args_match(ctx, sudoers_cmnd, sudoers_args) == ALLOW) {
      /* Open the file for fdexec or for digest matching. */
      if (!open_cmnd(ctx->user.cmnd, runchroot, digests, &fd))
    goto bad;
      if (digest_matches(fd, ctx->user.cmnd, runchroot, digests) != ALLOW)
    goto bad;

      /* Successful match. */
      free(ctx->runas.cmnd);
      if ((ctx->runas.cmnd = strdup(sudoers_cmnd)) == NULL) {
    sudo_warnx(U_("%s: %s"), __func__,
        U_("unable to allocate memory"));
    goto bad;
      }
      set_cmnd_fd(ctx, fd);
      debug_return_int(ALLOW);
  }
    }
bad:
    if (fd != -1)
  close(fd);
    debug_return_int(DENY);
}
#endif /* SUDOERS_NAME_MATCH */

/*
 * If path doesn't end in /, return ALLOW iff cmnd & path name the same inode;
 * otherwise, return ALLOW if ctx->user.cmnd names one of the inodes in path.
 * Returns DENY on failure.
 */
int
command_matches(struct sudoers_context *ctx, const char *sudoers_cmnd,
    const char *sudoers_args, const char *runchroot, struct cmnd_info *info,
    const struct command_digest_list *digests)
{
    char *saved_user_cmnd = NULL;
    struct stat saved_user_stat;
    int ret = DENY;
    debug_decl(command_matches, SUDOERS_DEBUG_MATCH);

    if (ctx->runas.chroot != NULL) {
  if (runchroot != NULL && strcmp(runchroot, "*") != 0 &&
    strcmp(runchroot, ctx->runas.chroot) != 0) {
      /* CHROOT mismatch */
      goto done;
  }
  /* User-specified runchroot (cmnd_stat already set appropriately). */
  runchroot = ctx->runas.chroot;
    } else if (runchroot == NULL) {
  /* No rule-specific runchroot, use global (cmnd_stat already set). */
  if (def_runchroot != NULL && strcmp(def_runchroot, "*") != '\0')
      runchroot = def_runchroot;
    } else {
  /* Rule-specific runchroot, must reset cmnd and cmnd_stat. */
  int status;

  /* Save old ctx->user.cmnd first, set_cmnd_path() will free it. */
  saved_user_cmnd = ctx->user.cmnd;
  ctx->user.cmnd = NULL;
  if (ctx->user.cmnd_stat != NULL)
      saved_user_stat = *ctx->user.cmnd_stat;
  status = set_cmnd_path(ctx, runchroot);
  if (status != FOUND) {
      ctx->user.cmnd = saved_user_cmnd;
      saved_user_cmnd = NULL;
  }
  if (info != NULL)
      info->status = status;
    }

    if (sudoers_cmnd == NULL) {
  sudoers_cmnd = "ALL";
  ret = command_matches_all(ctx, runchroot, digests);
  goto done;
    }

    /* Check for regular expressions first. */
    if (sudoers_cmnd[0] == '^') {
  ret = command_matches_regex(ctx, sudoers_cmnd, sudoers_args, runchroot,
      digests);
  goto done;
    }

    /* Check for pseudo-commands */
    if (sudoers_cmnd[0] != '/') {
  /*
   * Return true if sudoers_cmnd and cmnd match a pseudo-command AND
   *  a) there are no args in sudoers OR
   *  b) there are no args on command line and none req by sudoers OR
   *  c) there are args in sudoers and on command line and they match
   */
  if (strcmp(sudoers_cmnd, "list") == 0 ||
    strcmp(sudoers_cmnd, "sudoedit") == 0) {
      if (strcmp(ctx->user.cmnd, sudoers_cmnd) == 0 &&
        command_args_match(ctx, sudoers_cmnd, sudoers_args) == ALLOW) {
    /* No need to set ctx->user.cmnd since cmnd == sudoers_cmnd */
    ret = ALLOW;
      }
  }
  goto done;
    }

    if (has_meta(sudoers_cmnd)) {
  /*
   * If sudoers_cmnd has meta characters in it, we need to
   * use glob(3) and/or fnmatch(3) to do the matching.
   */
  if (def_fast_glob) {
      ret = command_matches_fnmatch(ctx, sudoers_cmnd, sudoers_args,
    runchroot, digests);
  } else {
      ret = command_matches_glob(ctx, sudoers_cmnd, sudoers_args,
    runchroot, digests);
  }
    } else {
  ret = command_matches_normal(ctx, sudoers_cmnd, sudoers_args,
      runchroot, digests);
    }
done:
    /* Restore ctx->user.cmnd and ctx->user.cmnd_stat. */
    if (saved_user_cmnd != NULL) {
  if (info != NULL) {
      free(info->cmnd_path);
      info->cmnd_path = ctx->user.cmnd;
      if (ctx->user.cmnd_stat != NULL)
    info->cmnd_stat = *ctx->user.cmnd_stat;
  } else {
      free(ctx->user.cmnd);
  }
  ctx->user.cmnd = saved_user_cmnd;
  if (ctx->user.cmnd_stat != NULL)
      *ctx->user.cmnd_stat = saved_user_stat;
    }
    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
  "user command \"%s%s%s\" matches sudoers command \"%s%s%s\"%s%s: %s",
  ctx->user.cmnd, ctx->user.cmnd_args ? " " : "",
  ctx->user.cmnd_args ? ctx->user.cmnd_args : "", sudoers_cmnd,
  sudoers_args ? " " : "", sudoers_args ? sudoers_args : "",
  runchroot ? ", chroot " : "", runchroot ? runchroot : "",
  ret == ALLOW ? "ALLOW" : "DENY");
    debug_return_int(ret);
}

Coverage Report

Created: 2025-10-13 06:08