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| author | Oleg Nesterov <oleg@redhat.com> | 2013-08-06 19:38:55 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-08-06 13:13:24 -0700 |
| commit | 6160968cee8b90a5dd95318d716e31d7775c4ef3 (patch) | |
| tree | 3183e99bd38da761532685c045c2eac29c80b0b9 /kernel | |
| parent | c095ba7224d8edc71dcef0d655911399a8bd4a3f (diff) | |
| download | lwn-6160968cee8b90a5dd95318d716e31d7775c4ef3.tar.gz lwn-6160968cee8b90a5dd95318d716e31d7775c4ef3.zip | |
userns: unshare_userns(&cred) should not populate cred on failure
unshare_userns(new_cred) does *new_cred = prepare_creds() before
create_user_ns() which can fail. However, the caller expects that
it doesn't need to take care of new_cred if unshare_userns() fails.
We could change the single caller, sys_unshare(), but I think it
would be more clean to avoid the side effects on failure, so with
this patch unshare_userns() does put_cred() itself and initializes
*new_cred only if create_user_ns() succeeeds.
Cc: stable@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/user_namespace.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index d8c30db06c5b..6e50a44610ee 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -105,16 +105,21 @@ int create_user_ns(struct cred *new) int unshare_userns(unsigned long unshare_flags, struct cred **new_cred) { struct cred *cred; + int err = -ENOMEM; if (!(unshare_flags & CLONE_NEWUSER)) return 0; cred = prepare_creds(); - if (!cred) - return -ENOMEM; + if (cred) { + err = create_user_ns(cred); + if (err) + put_cred(cred); + else + *new_cred = cred; + } - *new_cred = cred; - return create_user_ns(cred); + return err; } void free_user_ns(struct user_namespace *ns) |