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| author | Norman Wilson <norman@teach.cs.toronto.edu> | 2024-08-12 14:16:30 -0400 |
|---|---|---|
| committer | Bernd Schubert <bernd.schubert@fastmail.fm> | 2024-08-21 23:58:25 +0200 |
| commit | c9bf7d3e20ec5c86dd590f695b92e65142491d0e (patch) | |
| tree | cc59f1349331126ad505d3ae573f4bf0e4242d7e | |
| parent | 0750b4a194019c991d1c8a7f5e59fb5f4be50e3c (diff) | |
| download | libfuse-c9bf7d3e20ec5c86dd590f695b92e65142491d0e.tar.gz | |
Rearrange util/fusermount.c umount_fuse_locked() so that
umount2 is called with privs dropped, not raised. This
works around a clash with NFS permissions: if FUSE mounted
on NFS client directory with root_squash in effect, and
some directory in the path leading to the mount point denies
permissions to others, umount2 will fail because userid 0
cannot search it. Since drop_privs merely sets the file-
system user- and group-ID without changing the CAP_SYS_ADMIN
capability needed to unmount a file system (which fusermount
has because it is set-user-ID root), umount2 works fine.
| -rw-r--r-- | util/fusermount.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/util/fusermount.c b/util/fusermount.c index e40c457..f37c616 100644 --- a/util/fusermount.c +++ b/util/fusermount.c @@ -523,11 +523,13 @@ static int unmount_fuse_locked(const char *mnt, int quiet, int lazy) drop_privs(); res = chdir_to_parent(copy, &last); - restore_privs(); - if (res == -1) + if (res == -1) { + restore_privs(); goto out; + } res = umount2(last, umount_flags); + restore_privs(); if (res == -1 && !quiet) { fprintf(stderr, "%s: failed to unmount %s: %s\n", progname, mnt, strerror(errno)); |