From 053c095a82cf773075e83d7233b5cc19a1f73ece Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 16 Jan 2015 22:09:00 +0100 Subject: netlink: make nlmsg_end() and genlmsg_end() void Contrary to common expectations for an "int" return, these functions return only a positive value -- if used correctly they cannot even return 0 because the message header will necessarily be in the skb. This makes the very common pattern of if (genlmsg_end(...) < 0) { ... } be a whole bunch of dead code. Many places also simply do return nlmsg_end(...); and the caller is expected to deal with it. This also commonly (at least for me) causes errors, because it is very common to write if (my_function(...)) /* error condition */ and if my_function() does "return nlmsg_end()" this is of course wrong. Additionally, there's not a single place in the kernel that actually needs the message length returned, and if anyone needs it later then it'll be very easy to just use skb->len there. Remove this, and make the functions void. This removes a bunch of dead code as described above. The patch adds lines because I did - return nlmsg_end(...); + nlmsg_end(...); + return 0; I could have preserved all the function's return values by returning skb->len, but instead I've audited all the places calling the affected functions and found that none cared. A few places actually compared the return value with <= 0 in dump functionality, but that could just be changed to < 0 with no change in behaviour, so I opted for the more efficient version. One instance of the error I've made numerous times now is also present in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't check for <0 or <=0 and thus broke out of the loop every single time. I've preserved this since it will (I think) have caused the messages to userspace to be formatted differently with just a single message for every SKB returned to userspace. It's possible that this isn't needed for the tools that actually use this, but I don't even know what they are so couldn't test that changing this behaviour would be acceptable. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- net/nfc/netlink.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'net/nfc/netlink.c') diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c index 44989fc8cddf..be387e6219a0 100644 --- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -102,7 +102,8 @@ static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target, goto nla_put_failure; } - return genlmsg_end(msg, hdr); + genlmsg_end(msg, hdr); + return 0; nla_put_failure: genlmsg_cancel(msg, hdr); @@ -518,7 +519,8 @@ static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev, nla_put_u8(msg, NFC_ATTR_RF_MODE, dev->rf_mode)) goto nla_put_failure; - return genlmsg_end(msg, hdr); + genlmsg_end(msg, hdr); + return 0; nla_put_failure: genlmsg_cancel(msg, hdr); @@ -908,7 +910,8 @@ static int nfc_genl_send_params(struct sk_buff *msg, nla_put_u16(msg, NFC_ATTR_LLC_PARAM_MIUX, be16_to_cpu(local->miux))) goto nla_put_failure; - return genlmsg_end(msg, hdr); + genlmsg_end(msg, hdr); + return 0; nla_put_failure: @@ -1247,8 +1250,7 @@ static int nfc_genl_send_se(struct sk_buff *msg, struct nfc_dev *dev, nla_put_u8(msg, NFC_ATTR_SE_TYPE, se->type)) goto nla_put_failure; - if (genlmsg_end(msg, hdr) < 0) - goto nla_put_failure; + genlmsg_end(msg, hdr); } return 0; -- cgit v1.2.3 From 447b27c4f29b510b98e99395120d635f009ed563 Mon Sep 17 00:00:00 2001 From: Christophe Ricard Date: Sun, 1 Feb 2015 22:26:16 +0100 Subject: NFC: Forward NFC_EVT_TRANSACTION to user space NFC_EVT_TRANSACTION is sent through netlink in order for a specific application running on a secure element to notify userspace of an event. Typically the secure element application counterpart on the host could interpret that event and act upon it. Forwarded information contains: - SE host generating the event - Application IDentifier doing the operation - Applications parameters Signed-off-by: Christophe Ricard Signed-off-by: Samuel Ortiz --- include/net/nfc/nfc.h | 27 +++++++++++++++++++++++++++ include/uapi/linux/nfc.h | 1 + net/nfc/core.c | 21 +++++++++++++++++++++ net/nfc/netlink.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ net/nfc/nfc.h | 2 ++ 5 files changed, 98 insertions(+) (limited to 'net/nfc/netlink.c') diff --git a/include/net/nfc/nfc.h b/include/net/nfc/nfc.h index 12adb817c27a..73190e65d5c1 100644 --- a/include/net/nfc/nfc.h +++ b/include/net/nfc/nfc.h @@ -135,6 +135,31 @@ struct nfc_se { u16 state; }; +/** + * nfc_evt_transaction - A struct for NFC secure element event transaction. + * + * @aid: The application identifier triggering the event + * + * @aid_len: The application identifier length [5:16] + * + * @params: The application parameters transmitted during the transaction + * + * @params_len: The applications parameters length [0:255] + * + */ +#define NFC_MIN_AID_LENGTH 5 +#define NFC_MAX_AID_LENGTH 16 +#define NFC_MAX_PARAMS_LENGTH 255 + +#define NFC_EVT_TRANSACTION_AID_TAG 0x81 +#define NFC_EVT_TRANSACTION_PARAMS_TAG 0x82 +struct nfc_evt_transaction { + u32 aid_len; + u8 aid[NFC_MAX_AID_LENGTH]; + u8 params_len; + u8 params[NFC_MAX_PARAMS_LENGTH]; +} __packed; + struct nfc_genl_data { u32 poll_req_portid; struct mutex genl_data_mutex; @@ -262,6 +287,8 @@ int nfc_tm_data_received(struct nfc_dev *dev, struct sk_buff *skb); void nfc_driver_failure(struct nfc_dev *dev, int err); +int nfc_se_transaction(struct nfc_dev *dev, u8 se_idx, + struct nfc_evt_transaction *evt_transaction); int nfc_add_se(struct nfc_dev *dev, u32 se_idx, u16 type); int nfc_remove_se(struct nfc_dev *dev, u32 se_idx); struct nfc_se *nfc_find_se(struct nfc_dev *dev, u32 se_idx); diff --git a/include/uapi/linux/nfc.h b/include/uapi/linux/nfc.h index 8119255feae4..c1e2e63cf9b5 100644 --- a/include/uapi/linux/nfc.h +++ b/include/uapi/linux/nfc.h @@ -183,6 +183,7 @@ enum nfc_attrs { NFC_ATTR_SE_APDU, NFC_ATTR_TARGET_ISO15693_DSFID, NFC_ATTR_TARGET_ISO15693_UID, + NFC_ATTR_SE_PARAMS, /* private: internal use only */ __NFC_ATTR_AFTER_LAST }; diff --git a/net/nfc/core.c b/net/nfc/core.c index 7f1b6351755c..cff3f1614ad4 100644 --- a/net/nfc/core.c +++ b/net/nfc/core.c @@ -932,6 +932,27 @@ int nfc_remove_se(struct nfc_dev *dev, u32 se_idx) } EXPORT_SYMBOL(nfc_remove_se); +int nfc_se_transaction(struct nfc_dev *dev, u8 se_idx, + struct nfc_evt_transaction *evt_transaction) +{ + int rc; + + pr_debug("transaction: %x\n", se_idx); + + device_lock(&dev->dev); + + if (!evt_transaction) { + rc = -EPROTO; + goto out; + } + + rc = nfc_genl_se_transaction(dev, se_idx, evt_transaction); +out: + device_unlock(&dev->dev); + return rc; +} +EXPORT_SYMBOL(nfc_se_transaction); + static void nfc_release(struct device *d) { struct nfc_dev *dev = to_nfc_dev(d); diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c index be387e6219a0..14a2d11581da 100644 --- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -497,6 +497,53 @@ free_msg: return -EMSGSIZE; } +int nfc_genl_se_transaction(struct nfc_dev *dev, u8 se_idx, + struct nfc_evt_transaction *evt_transaction) +{ + struct nfc_se *se; + struct sk_buff *msg; + void *hdr; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!msg) + return -ENOMEM; + + hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0, + NFC_EVENT_SE_TRANSACTION); + if (!hdr) + goto free_msg; + + se = nfc_find_se(dev, se_idx); + if (!se) + goto free_msg; + + if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx) || + nla_put_u32(msg, NFC_ATTR_SE_INDEX, se_idx) || + nla_put_u8(msg, NFC_ATTR_SE_TYPE, se->type) || + nla_put(msg, NFC_ATTR_SE_AID, evt_transaction->aid_len, + evt_transaction->aid) || + nla_put(msg, NFC_ATTR_SE_PARAMS, evt_transaction->params_len, + evt_transaction->params)) + goto nla_put_failure; + + /* evt_transaction is no more used */ + devm_kfree(&dev->dev, evt_transaction); + + genlmsg_end(msg, hdr); + + genlmsg_multicast(&nfc_genl_family, msg, 0, 0, GFP_KERNEL); + + return 0; + +nla_put_failure: + genlmsg_cancel(msg, hdr); +free_msg: + /* evt_transaction is no more used */ + devm_kfree(&dev->dev, evt_transaction); + nlmsg_free(msg); + return -EMSGSIZE; +} + static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev, u32 portid, u32 seq, struct netlink_callback *cb, diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h index 88d60064890e..a8ce80b47720 100644 --- a/net/nfc/nfc.h +++ b/net/nfc/nfc.h @@ -100,6 +100,8 @@ int nfc_genl_llc_send_sdres(struct nfc_dev *dev, struct hlist_head *sdres_list); int nfc_genl_se_added(struct nfc_dev *dev, u32 se_idx, u16 type); int nfc_genl_se_removed(struct nfc_dev *dev, u32 se_idx); +int nfc_genl_se_transaction(struct nfc_dev *dev, u8 se_idx, + struct nfc_evt_transaction *evt_transaction); struct nfc_dev *nfc_get_device(unsigned int idx); -- cgit v1.2.3