diff options
| -rw-r--r-- | fs/smb/client/cifs_spnego.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/smb/client/cifs_spnego.c b/fs/smb/client/cifs_spnego.c index 3a41bbada04c..44c407275680 100644 --- a/fs/smb/client/cifs_spnego.c +++ b/fs/smb/client/cifs_spnego.c @@ -8,6 +8,7 @@ */ #include <linux/list.h> +#include <linux/cred.h> #include <linux/slab.h> #include <linux/string.h> #include <keys/user-type.h> @@ -40,12 +41,27 @@ cifs_spnego_key_destroy(struct key *key) kfree(key->payload.data[0]); } +static int +cifs_spnego_key_vet_description(const char *description) +{ + /* + * cifs.spnego descriptions are authority-bearing inputs to cifs.upcall. + * They are only valid when produced by CIFS while using the private + * spnego_cred installed below. Do not let userspace create this type + * of key through request_key(2)/add_key(2), since the helper treats + * pid/uid/creduid/upcall_target as kernel-originating fields. + */ + if (current_cred() != spnego_cred) + return -EPERM; + return 0; +} /* * keytype for CIFS spnego keys */ struct key_type cifs_spnego_key_type = { .name = "cifs.spnego", + .vet_description = cifs_spnego_key_vet_description, .instantiate = cifs_spnego_key_instantiate, .destroy = cifs_spnego_key_destroy, .describe = user_describe, |