diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2017-10-03 16:15:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-10-03 17:54:25 -0700 |
| commit | 43a4f2619038002f48c78698c42c05692d4b4eb2 (patch) | |
| tree | ca46e0bb1cbd6a522131f473ce7d7a4d9fe64a43 | |
| parent | eb23aa0317eb1f08e8d9d36b8753d42f03b32764 (diff) | |
| download | linux-43a4f2619038002f48c78698c42c05692d4b4eb2.tar.bz2 | |
exec: binfmt_misc: fix race between load_misc_binary() and kill_node()
load_misc_binary() makes a local copy of fmt->interpreter under
entries_lock to avoid the race with kill_node() but this is not enough;
the whole Node can be freed after we drop entries_lock, not only the
->interpreter string.
Add dget/dput(fmt->dentry) to ensure bm_evict_inode() can't destroy/free
this Node.
Link: http://lkml.kernel.org/r/20170922143650.GA17227@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ben Woodard <woodard@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jim Foraker <foraker1@llnl.gov>
Cc: Travis Gummels <tgummels@redhat.com>
Cc: <tdhooge@llnl.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/binfmt_misc.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index babfe7bd56f0..f5f8c2541790 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -138,20 +138,23 @@ static int load_misc_binary(struct linux_binprm *bprm) retval = -ENOEXEC; if (!enabled) - goto ret; + return retval; /* to keep locking time low, we copy the interpreter string */ read_lock(&entries_lock); fmt = check_file(bprm); - if (fmt) + if (fmt) { + dget(fmt->dentry); strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); + } read_unlock(&entries_lock); if (!fmt) - goto ret; + return retval; /* Need to be able to load the file after exec */ + retval = -ENOENT; if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) - return -ENOENT; + goto ret; if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { retval = remove_arg_zero(bprm); @@ -238,6 +241,7 @@ static int load_misc_binary(struct linux_binprm *bprm) goto error; ret: + dput(fmt->dentry); return retval; error: if (fd_binary > 0) |