diff options
Diffstat (limited to 'net/nfc/llcp_core.c')
-rw-r--r-- | net/nfc/llcp_core.c | 163 |
1 files changed, 116 insertions, 47 deletions
diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index cc997518f79d..da3cb0d29b97 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -17,6 +17,8 @@ static u8 llcp_magic[3] = {0x46, 0x66, 0x6d}; static LIST_HEAD(llcp_devices); +/* Protects llcp_devices list */ +static DEFINE_SPINLOCK(llcp_devices_lock); static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb); @@ -143,8 +145,15 @@ static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device, write_unlock(&local->raw_sockets.lock); } -struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local) +static struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local) { + /* Since using nfc_llcp_local may result in usage of nfc_dev, whenever + * we hold a reference to local, we also need to hold a reference to + * the device to avoid UAF. + */ + if (!nfc_get_device(local->dev->idx)) + return NULL; + kref_get(&local->ref); return local; @@ -159,6 +168,7 @@ static void local_cleanup(struct nfc_llcp_local *local) cancel_work_sync(&local->rx_work); cancel_work_sync(&local->timeout_work); kfree_skb(local->rx_pending); + local->rx_pending = NULL; del_timer_sync(&local->sdreq_timer); cancel_work_sync(&local->sdreq_timeout_work); nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs); @@ -170,17 +180,24 @@ static void local_release(struct kref *ref) local = container_of(ref, struct nfc_llcp_local, ref); - list_del(&local->list); local_cleanup(local); kfree(local); } int nfc_llcp_local_put(struct nfc_llcp_local *local) { + struct nfc_dev *dev; + int ret; + if (local == NULL) return 0; - return kref_put(&local->ref, local_release); + dev = local->dev; + + ret = kref_put(&local->ref, local_release); + nfc_put_device(dev); + + return ret; } static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local, @@ -203,17 +220,13 @@ static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local, if (tmp_sock->ssap == ssap && tmp_sock->dsap == dsap) { llcp_sock = tmp_sock; + sock_hold(&llcp_sock->sk); break; } } read_unlock(&local->sockets.lock); - if (llcp_sock == NULL) - return NULL; - - sock_hold(&llcp_sock->sk); - return llcp_sock; } @@ -283,12 +296,33 @@ static void nfc_llcp_sdreq_timer(struct timer_list *t) struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev) { struct nfc_llcp_local *local; + struct nfc_llcp_local *res = NULL; + spin_lock(&llcp_devices_lock); list_for_each_entry(local, &llcp_devices, list) - if (local->dev == dev) + if (local->dev == dev) { + res = nfc_llcp_local_get(local); + break; + } + spin_unlock(&llcp_devices_lock); + + return res; +} + +static struct nfc_llcp_local *nfc_llcp_remove_local(struct nfc_dev *dev) +{ + struct nfc_llcp_local *local, *tmp; + + spin_lock(&llcp_devices_lock); + list_for_each_entry_safe(local, tmp, &llcp_devices, list) + if (local->dev == dev) { + list_del(&local->list); + spin_unlock(&llcp_devices_lock); return local; + } + spin_unlock(&llcp_devices_lock); - pr_debug("No device found\n"); + pr_warn("Shutting down device not found\n"); return NULL; } @@ -301,7 +335,7 @@ static char *wks[] = { "urn:nfc:sn:snep", }; -static int nfc_llcp_wks_sap(char *service_name, size_t service_name_len) +static int nfc_llcp_wks_sap(const char *service_name, size_t service_name_len) { int sap, num_wks; @@ -325,7 +359,8 @@ static int nfc_llcp_wks_sap(char *service_name, size_t service_name_len) static struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local, - u8 *sn, size_t sn_len) + const u8 *sn, size_t sn_len, + bool needref) { struct sock *sk; struct nfc_llcp_sock *llcp_sock, *tmp_sock; @@ -361,6 +396,8 @@ struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local, if (memcmp(sn, tmp_sock->service_name, sn_len) == 0) { llcp_sock = tmp_sock; + if (needref) + sock_hold(&llcp_sock->sk); break; } } @@ -402,7 +439,8 @@ u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local, * to this service name. */ if (nfc_llcp_sock_from_sn(local, sock->service_name, - sock->service_name_len) != NULL) { + sock->service_name_len, + false) != NULL) { mutex_unlock(&local->sdp_lock); return LLCP_SAP_MAX; @@ -522,7 +560,7 @@ static int nfc_llcp_build_gb(struct nfc_llcp_local *local) { u8 *gb_cur, version, version_length; u8 lto_length, wks_length, miux_length; - u8 *version_tlv = NULL, *lto_tlv = NULL, + const u8 *version_tlv = NULL, *lto_tlv = NULL, *wks_tlv = NULL, *miux_tlv = NULL; __be16 wks = cpu_to_be16(local->local_wks); u8 gb_len = 0; @@ -609,12 +647,15 @@ u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len) *general_bytes_len = local->gb_len; + nfc_llcp_local_put(local); + return local->gb; } -int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len) +int nfc_llcp_set_remote_gb(struct nfc_dev *dev, const u8 *gb, u8 gb_len) { struct nfc_llcp_local *local; + int err; if (gb_len < 3 || gb_len > NFC_MAX_GT_LEN) return -EINVAL; @@ -631,35 +672,39 @@ int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len) if (memcmp(local->remote_gb, llcp_magic, 3)) { pr_err("MAC does not support LLCP\n"); - return -EINVAL; + err = -EINVAL; + goto out; } - return nfc_llcp_parse_gb_tlv(local, + err = nfc_llcp_parse_gb_tlv(local, &local->remote_gb[3], local->remote_gb_len - 3); +out: + nfc_llcp_local_put(local); + return err; } -static u8 nfc_llcp_dsap(struct sk_buff *pdu) +static u8 nfc_llcp_dsap(const struct sk_buff *pdu) { return (pdu->data[0] & 0xfc) >> 2; } -static u8 nfc_llcp_ptype(struct sk_buff *pdu) +static u8 nfc_llcp_ptype(const struct sk_buff *pdu) { return ((pdu->data[0] & 0x03) << 2) | ((pdu->data[1] & 0xc0) >> 6); } -static u8 nfc_llcp_ssap(struct sk_buff *pdu) +static u8 nfc_llcp_ssap(const struct sk_buff *pdu) { return pdu->data[1] & 0x3f; } -static u8 nfc_llcp_ns(struct sk_buff *pdu) +static u8 nfc_llcp_ns(const struct sk_buff *pdu) { return pdu->data[2] >> 4; } -static u8 nfc_llcp_nr(struct sk_buff *pdu) +static u8 nfc_llcp_nr(const struct sk_buff *pdu) { return pdu->data[2] & 0xf; } @@ -801,23 +846,15 @@ out: } static struct nfc_llcp_sock *nfc_llcp_sock_get_sn(struct nfc_llcp_local *local, - u8 *sn, size_t sn_len) + const u8 *sn, size_t sn_len) { - struct nfc_llcp_sock *llcp_sock; - - llcp_sock = nfc_llcp_sock_from_sn(local, sn, sn_len); - - if (llcp_sock == NULL) - return NULL; - - sock_hold(&llcp_sock->sk); - - return llcp_sock; + return nfc_llcp_sock_from_sn(local, sn, sn_len, true); } -static u8 *nfc_llcp_connect_sn(struct sk_buff *skb, size_t *sn_len) +static const u8 *nfc_llcp_connect_sn(const struct sk_buff *skb, size_t *sn_len) { - u8 *tlv = &skb->data[2], type, length; + u8 type, length; + const u8 *tlv = &skb->data[2]; size_t tlv_array_len = skb->len - LLCP_HEADER_SIZE, offset = 0; while (offset < tlv_array_len) { @@ -875,7 +912,7 @@ static void nfc_llcp_recv_ui(struct nfc_llcp_local *local, } static void nfc_llcp_recv_connect(struct nfc_llcp_local *local, - struct sk_buff *skb) + const struct sk_buff *skb) { struct sock *new_sk, *parent; struct nfc_llcp_sock *sock, *new_sock; @@ -893,7 +930,7 @@ static void nfc_llcp_recv_connect(struct nfc_llcp_local *local, goto fail; } } else { - u8 *sn; + const u8 *sn; size_t sn_len; sn = nfc_llcp_connect_sn(skb, &sn_len); @@ -946,8 +983,17 @@ static void nfc_llcp_recv_connect(struct nfc_llcp_local *local, } new_sock = nfc_llcp_sock(new_sk); - new_sock->dev = local->dev; + new_sock->local = nfc_llcp_local_get(local); + if (!new_sock->local) { + reason = LLCP_DM_REJ; + sock_put(&new_sock->sk); + release_sock(&sock->sk); + sock_put(&sock->sk); + goto fail; + } + + new_sock->dev = local->dev; new_sock->rw = sock->rw; new_sock->miux = sock->miux; new_sock->nfc_protocol = sock->nfc_protocol; @@ -1112,7 +1158,7 @@ static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local, } static void nfc_llcp_recv_disc(struct nfc_llcp_local *local, - struct sk_buff *skb) + const struct sk_buff *skb) { struct nfc_llcp_sock *llcp_sock; struct sock *sk; @@ -1155,7 +1201,8 @@ static void nfc_llcp_recv_disc(struct nfc_llcp_local *local, nfc_llcp_sock_put(llcp_sock); } -static void nfc_llcp_recv_cc(struct nfc_llcp_local *local, struct sk_buff *skb) +static void nfc_llcp_recv_cc(struct nfc_llcp_local *local, + const struct sk_buff *skb) { struct nfc_llcp_sock *llcp_sock; struct sock *sk; @@ -1188,7 +1235,8 @@ static void nfc_llcp_recv_cc(struct nfc_llcp_local *local, struct sk_buff *skb) nfc_llcp_sock_put(llcp_sock); } -static void nfc_llcp_recv_dm(struct nfc_llcp_local *local, struct sk_buff *skb) +static void nfc_llcp_recv_dm(struct nfc_llcp_local *local, + const struct sk_buff *skb) { struct nfc_llcp_sock *llcp_sock; struct sock *sk; @@ -1226,12 +1274,13 @@ static void nfc_llcp_recv_dm(struct nfc_llcp_local *local, struct sk_buff *skb) } static void nfc_llcp_recv_snl(struct nfc_llcp_local *local, - struct sk_buff *skb) + const struct sk_buff *skb) { struct nfc_llcp_sock *llcp_sock; - u8 dsap, ssap, *tlv, type, length, tid, sap; + u8 dsap, ssap, type, length, tid, sap; + const u8 *tlv; u16 tlv_len, offset; - char *service_name; + const char *service_name; size_t service_name_len; struct nfc_llcp_sdp_tlv *sdp; HLIST_HEAD(llc_sdres_list); @@ -1273,7 +1322,8 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local, } llcp_sock = nfc_llcp_sock_from_sn(local, service_name, - service_name_len); + service_name_len, + true); if (!llcp_sock) { sap = 0; goto add_snl; @@ -1293,6 +1343,7 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local, if (sap == LLCP_SAP_MAX) { sap = 0; + nfc_llcp_sock_put(llcp_sock); goto add_snl; } @@ -1310,6 +1361,7 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local, pr_debug("%p %d\n", llcp_sock, sap); + nfc_llcp_sock_put(llcp_sock); add_snl: sdp = nfc_llcp_build_sdres_tlv(tid, sap); if (sdp == NULL) @@ -1522,6 +1574,8 @@ int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb) __nfc_llcp_recv(local, skb); + nfc_llcp_local_put(local); + return 0; } @@ -1538,6 +1592,8 @@ void nfc_llcp_mac_is_down(struct nfc_dev *dev) /* Close and purge all existing sockets */ nfc_llcp_socket_release(local, true, 0); + + nfc_llcp_local_put(local); } void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx, @@ -1563,6 +1619,8 @@ void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx, mod_timer(&local->link_timer, jiffies + msecs_to_jiffies(local->remote_lto)); } + + nfc_llcp_local_put(local); } int nfc_llcp_register_device(struct nfc_dev *ndev) @@ -1573,7 +1631,16 @@ int nfc_llcp_register_device(struct nfc_dev *ndev) if (local == NULL) return -ENOMEM; - local->dev = ndev; + /* As we are going to initialize local's refcount, we need to get the + * nfc_dev to avoid UAF, otherwise there is no point in continuing. + * See nfc_llcp_local_get(). + */ + local->dev = nfc_get_device(ndev->idx); + if (!local->dev) { + kfree(local); + return -ENODEV; + } + INIT_LIST_HEAD(&local->list); kref_init(&local->ref); mutex_init(&local->sdp_lock); @@ -1606,14 +1673,16 @@ int nfc_llcp_register_device(struct nfc_dev *ndev) timer_setup(&local->sdreq_timer, nfc_llcp_sdreq_timer, 0); INIT_WORK(&local->sdreq_timeout_work, nfc_llcp_sdreq_timeout_work); + spin_lock(&llcp_devices_lock); list_add(&local->list, &llcp_devices); + spin_unlock(&llcp_devices_lock); return 0; } void nfc_llcp_unregister_device(struct nfc_dev *dev) { - struct nfc_llcp_local *local = nfc_llcp_find_local(dev); + struct nfc_llcp_local *local = nfc_llcp_remove_local(dev); if (local == NULL) { pr_debug("No such device\n"); |