A SID could potentially be embedded inside of payload.value if there are no subauthorities, and the arch has 8 byte pointers. Allow for that possibility there.
While we're at it, rephrase the "embedding" check in terms of key->payload to allow for the possibility that the union might change size in the future. Signed-off-by: Jeff Layton <[email protected]> --- fs/cifs/cifsacl.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index 664abc3..bbe7928 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -63,7 +63,7 @@ cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep) * With this however, you must check the datalen before trying to * dereference payload.data! */ - if (prep->datalen <= sizeof(void *)) { + if (prep->datalen <= sizeof(key->payload)) { key->payload.value = 0; memcpy(&key->payload.value, prep->data, prep->datalen); key->datalen = prep->datalen; @@ -82,7 +82,7 @@ cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep) static inline void cifs_idmap_key_destroy(struct key *key) { - if (key->datalen > sizeof(void *)) + if (key->datalen > sizeof(key->payload)) kfree(key->payload.data); } @@ -222,7 +222,15 @@ id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid) goto invalidate_key; } - ksid = (struct cifs_sid *)sidkey->payload.data; + /* + * A sid is usually too large to be embedded in payload.value, but if + * there are no subauthorities and the host has 8-byte pointers, then + * it could be. + */ + ksid = sidkey->datalen <= sizeof(sidkey->payload) ? + (struct cifs_sid *)&sidkey->payload.value : + (struct cifs_sid *)sidkey->payload.data; + ksid_size = CIFS_SID_BASE_SIZE + (ksid->num_subauth * sizeof(__le32)); if (ksid_size > sidkey->datalen) { rc = -EIO; @@ -230,6 +238,7 @@ id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid) "ksid_size=%u)", __func__, sidkey->datalen, ksid_size); goto invalidate_key; } + cifs_copy_sid(ssid, ksid); key_set_timeout(sidkey, cifs_idmap_cache_timeout); out_key_put: -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
