diff options
| -rw-r--r-- | sbin/mksnap_ffs/mksnap_ffs.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/sbin/mksnap_ffs/mksnap_ffs.c b/sbin/mksnap_ffs/mksnap_ffs.c index 58e73dc..13186b4 100644 --- a/sbin/mksnap_ffs/mksnap_ffs.c +++ b/sbin/mksnap_ffs/mksnap_ffs.c @@ -43,6 +43,7 @@ #include <errno.h> #include <fcntl.h> #include <grp.h> +#include <limits.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -54,7 +55,7 @@ void usage(void); int main(int argc, char **argv) { - const char *dir; + char *dir, *cp, path[PATH_MAX]; struct ufs_args args; struct group *grp; struct stat stbuf; @@ -66,6 +67,37 @@ main(int argc, char **argv) dir = argv[1]; args.fspec = argv[2]; + /* + * Check that the user running this program has permission + * to create and remove a snapshot file from the directory + * in which they have requested to have it made. If the + * directory is sticky and not owned by the user, then they + * will not be able to remove the snapshot when they are + * done with it. + */ + if (strlen(args.fspec) >= PATH_MAX) + errx(1, "pathname too long %s", args.fspec); + cp = strrchr(args.fspec, '/'); + if (cp == NULL) { + strlcpy(path, ".", PATH_MAX); + } else if (cp == args.fspec) { + strlcpy(path, "/", PATH_MAX); + } else { + strlcpy(path, args.fspec, cp - args.fspec + 1); + } + if (stat(path, &stbuf) < 0) + err(1, "%s", path); + if (!S_ISDIR(stbuf.st_mode)) + errx(1, "%s: Not a directory", path); + if (access(path, W_OK) < 0) + err(1, "Lack write permission in %s", path); + if ((stbuf.st_mode & S_ISTXT) && stbuf.st_uid != getuid()) + errx(1, "Lack write permission in %s: Sticky bit set", path); + + /* + * Having verified access to the directory in which the + * snapshot is to be built, proceed with creating it. + */ if ((grp = getgrnam("operator")) == NULL) errx(1, "Cannot retrieve operator gid"); if (mount("ffs", dir, MNT_UPDATE | MNT_SNAPSHOT, &args) < 0) |
