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NFC: Fix the number of pipes

PATCH In review Suren Baghdasaryan 2 participants 2 messages Aug 14, 2018

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Networking Network drivers NFC
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Suren Baghdasaryan

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#0 lore raw

PATCH 1/1 NFC: Fix the number of pipes

According to ETSI TS 102 622 specification chapter 4.4 pipe identifier is 7 bits long which allows for 128 unique pipe IDs. Because NFC_HCI_MAX_PIPES is used as the number of pipes supported and not as the max pipe ID, its value should be 128 instead of 127.

nfc_hci_recv_from_llc extracts pipe ID from packet header using NFC_HCI_FRAGMENT(0x7F) mask which allows for pipe ID value of 127. Same happens when NCI_HCP_MSG_GET_PIPE() is being used. With pipes array having only 127 elements and pipe ID of 127 the OOB memory access will result.

Suggested-by Dan Carpenter <[email protected]>
Signed-off-by Suren Baghdasaryan <[email protected]>
---
 include/net/nfc/hci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
include/net/nfc/hci.h +1 -1
index 316694dafa5b..008f466d1da7 100644
@@ -87,7 +87,7 @@ struct nfc_hci_pipe {
  * According to specification 102 622 chapter 4.4 Pipes,
  * the pipe identifier is 7 bits long.
  */
-#define NFC_HCI_MAX_PIPES		127
+#define NFC_HCI_MAX_PIPES		128
 struct nfc_hci_init_data {
 	u8 gate_count;
 	struct nfc_hci_gate gates[NFC_HCI_MAX_CUSTOM_GATES];
Signature · 1 line
2.18.0.865.gffc8e1a3cd6-goog
Reviewed-by on v1 1/1
#1 lore raw
Quoted 5 lines · Suren Baghdasaryan

According to ETSI TS 102 622 specification chapter 4.4 pipe identifier is 7 bits long which allows for 128 unique pipe IDs. Because NFC_HCI_MAX_PIPES is used as the number of pipes supported and not as the max pipe ID, its value should be 128 instead of 127.

Quoted 8 lines

nfc_hci_recv_from_llc extracts pipe ID from packet header using NFC_HCI_FRAGMENT(0x7F) mask which allows for pipe ID value of 127. Same happens when NCI_HCP_MSG_GET_PIPE() is being used. With pipes array having only 127 elements and pipe ID of 127 the OOB memory access will result.

Suggested-by Dan Carpenter <[email protected]>
Signed-off-by Suren Baghdasaryan <[email protected]>
Reviewed-by Kees Cook <[email protected]>

-Kees

Quoted 20 lines
---
 include/net/nfc/hci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
include/net/nfc/hci.h +1 -2
index 316694dafa5b..008f466d1da7 100644
@@ -87,7 +87,7 @@ struct nfc_hci_pipe {
  * According to specification 102 622 chapter 4.4 Pipes,
  * the pipe identifier is 7 bits long.
  */
-#define NFC_HCI_MAX_PIPES              127
+#define NFC_HCI_MAX_PIPES              128
 struct nfc_hci_init_data {
        u8 gate_count;
        struct nfc_hci_gate gates[NFC_HCI_MAX_CUSTOM_GATES];
--

2.18.0.865.gffc8e1a3cd6-goog

Signature · 2 lines
Kees Cook
Pixel Security