From c60c152230828825c06e62a8f1ce956d4b659266 Mon Sep 17 00:00:00 2001 From: Martin Faltesek Date: Mon, 21 Nov 2022 18:42:44 -0600 Subject: nfc: st-nci: fix incorrect validating logic in EVT_TRANSACTION The first validation check for EVT_TRANSACTION has two different checks tied together with logical AND. One is a check for minimum packet length, and the other is for a valid aid_tag. If either condition is true (fails), then an error should be triggered. The fix is to change && to ||. Reported-by: Denis Efremov Reviewed-by: Guenter Roeck Fixes: 5d1ceb7f5e56 ("NFC: st21nfcb: Add HCI transaction event support") Signed-off-by: Martin Faltesek Reviewed-by: Krzysztof Kozlowski Signed-off-by: Jakub Kicinski --- drivers/nfc/st-nci/se.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/nfc/st-nci') diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c index 7764b1a4c3cf..589e1dec78e7 100644 --- a/drivers/nfc/st-nci/se.c +++ b/drivers/nfc/st-nci/se.c @@ -326,7 +326,7 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, * AID 81 5 to 16 * PARAMETERS 82 0 to 255 */ - if (skb->len < NFC_MIN_AID_LENGTH + 2 && + if (skb->len < NFC_MIN_AID_LENGTH + 2 || skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG) return -EPROTO; -- cgit v1.2.3 From 440f2ae9c9f06e26f5dcea697a53717fc61a318c Mon Sep 17 00:00:00 2001 From: Martin Faltesek Date: Mon, 21 Nov 2022 18:42:45 -0600 Subject: nfc: st-nci: fix memory leaks in EVT_TRANSACTION Error path does not free previously allocated memory. Add devm_kfree() to the failure path. Reported-by: Denis Efremov Reviewed-by: Guenter Roeck Fixes: 5d1ceb7f5e56 ("NFC: st21nfcb: Add HCI transaction event support") Signed-off-by: Martin Faltesek Reviewed-by: Krzysztof Kozlowski Signed-off-by: Jakub Kicinski --- drivers/nfc/st-nci/se.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/nfc/st-nci') diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c index 589e1dec78e7..fc59916ae5ae 100644 --- a/drivers/nfc/st-nci/se.c +++ b/drivers/nfc/st-nci/se.c @@ -339,8 +339,10 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, /* Check next byte is PARAMETERS tag (82) */ if (skb->data[transaction->aid_len + 2] != - NFC_EVT_TRANSACTION_PARAMS_TAG) + NFC_EVT_TRANSACTION_PARAMS_TAG) { + devm_kfree(dev, transaction); return -EPROTO; + } transaction->params_len = skb->data[transaction->aid_len + 3]; memcpy(transaction->params, skb->data + -- cgit v1.2.3 From 0254f31a7df3bb3b90c2d9dd2d4052f7b95eb287 Mon Sep 17 00:00:00 2001 From: Martin Faltesek Date: Mon, 21 Nov 2022 18:42:46 -0600 Subject: nfc: st-nci: fix incorrect sizing calculations in EVT_TRANSACTION The transaction buffer is allocated by using the size of the packet buf, and subtracting two which seems intended to remove the two tags which are not present in the target structure. This calculation leads to under counting memory because of differences between the packet contents and the target structure. The aid_len field is a u8 in the packet, but a u32 in the structure, resulting in at least 3 bytes always being under counted. Further, the aid data is a variable length field in the packet, but fixed in the structure, so if this field is less than the max, the difference is added to the under counting. To fix, perform validation checks progressively to safely reach the next field, to determine the size of both buffers and verify both tags. Once all validation checks pass, allocate the buffer and copy the data. This eliminates freeing memory on the error path, as validation checks are moved ahead of memory allocation. Reported-by: Denis Efremov Reviewed-by: Guenter Roeck Fixes: 5d1ceb7f5e56 ("NFC: st21nfcb: Add HCI transaction event support") Signed-off-by: Martin Faltesek Reviewed-by: Krzysztof Kozlowski Signed-off-by: Jakub Kicinski --- drivers/nfc/st-nci/se.c | 51 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 36 insertions(+), 15 deletions(-) (limited to 'drivers/nfc/st-nci') diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c index fc59916ae5ae..ec87dd21e054 100644 --- a/drivers/nfc/st-nci/se.c +++ b/drivers/nfc/st-nci/se.c @@ -312,6 +312,8 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, int r = 0; struct device *dev = &ndev->nfc_dev->dev; struct nfc_evt_transaction *transaction; + u32 aid_len; + u8 params_len; pr_debug("connectivity gate event: %x\n", event); @@ -325,28 +327,47 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, * Description Tag Length * AID 81 5 to 16 * PARAMETERS 82 0 to 255 + * + * The key differences are aid storage length is variably sized + * in the packet, but fixed in nfc_evt_transaction, and that + * the aid_len is u8 in the packet, but u32 in the structure, + * and the tags in the packet are not included in + * nfc_evt_transaction. + * + * size(b): 1 1 5-16 1 1 0-255 + * offset: 0 1 2 aid_len + 2 aid_len + 3 aid_len + 4 + * mem name: aid_tag(M) aid_len aid params_tag(M) params_len params + * example: 0x81 5-16 X 0x82 0-255 X */ - if (skb->len < NFC_MIN_AID_LENGTH + 2 || - skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG) + if (skb->len < 2 || skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG) return -EPROTO; - transaction = devm_kzalloc(dev, skb->len - 2, GFP_KERNEL); - if (!transaction) - return -ENOMEM; + aid_len = skb->data[1]; - transaction->aid_len = skb->data[1]; - memcpy(transaction->aid, &skb->data[2], transaction->aid_len); + if (skb->len < aid_len + 4 || + aid_len > sizeof(transaction->aid)) + return -EPROTO; - /* Check next byte is PARAMETERS tag (82) */ - if (skb->data[transaction->aid_len + 2] != - NFC_EVT_TRANSACTION_PARAMS_TAG) { - devm_kfree(dev, transaction); + params_len = skb->data[aid_len + 3]; + + /* Verify PARAMETERS tag is (82), and final check that there is + * enough space in the packet to read everything. + */ + if (skb->data[aid_len + 2] != NFC_EVT_TRANSACTION_PARAMS_TAG || + skb->len < aid_len + 4 + params_len) return -EPROTO; - } - transaction->params_len = skb->data[transaction->aid_len + 3]; - memcpy(transaction->params, skb->data + - transaction->aid_len + 4, transaction->params_len); + transaction = devm_kzalloc(dev, sizeof(*transaction) + + params_len, GFP_KERNEL); + if (!transaction) + return -ENOMEM; + + transaction->aid_len = aid_len; + transaction->params_len = params_len; + + memcpy(transaction->aid, &skb->data[2], aid_len); + memcpy(transaction->params, &skb->data[aid_len + 4], + params_len); r = nfc_se_transaction(ndev->nfc_dev, host, transaction); break; -- cgit v1.2.3