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authorPablo Neira Ayuso <pablo@netfilter.org>2020-05-14 14:14:23 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2020-05-25 20:39:14 +0200
commit4c559f15efcc43b996f4da528cd7f9483aaca36d (patch)
treea6a8ccd47c3fc1afdac3c51f6380d3a6ca1b7c19 /net
parenta164b95ad6055c50612795882f35e0efda1f1390 (diff)
netfilter: nf_conntrack_pptp: prevent buffer overflows in debug code
Dan Carpenter says: "Smatch complains that the value for "cmd" comes from the network and can't be trusted." Add pptp_msg_name() helper function that checks for the array boundary. Fixes: f09943fefe6b ("[NETFILTER]: nf_conntrack/nf_nat: add PPTP helper port") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/netfilter/nf_nat_pptp.c7
-rw-r--r--net/netfilter/nf_conntrack_pptp.c62
2 files changed, 37 insertions, 32 deletions
diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
index 3c25a467b3ef..7afde8828b4c 100644
--- a/net/ipv4/netfilter/nf_nat_pptp.c
+++ b/net/ipv4/netfilter/nf_nat_pptp.c
@@ -166,8 +166,7 @@ pptp_outbound_pkt(struct sk_buff *skb,
break;
default:
pr_debug("unknown outbound packet 0x%04x:%s\n", msg,
- msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] :
- pptp_msg_name[0]);
+ pptp_msg_name(msg));
fallthrough;
case PPTP_SET_LINK_INFO:
/* only need to NAT in case PAC is behind NAT box */
@@ -268,9 +267,7 @@ pptp_inbound_pkt(struct sk_buff *skb,
pcid_off = offsetof(union pptp_ctrl_union, setlink.peersCallID);
break;
default:
- pr_debug("unknown inbound packet %s\n",
- msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] :
- pptp_msg_name[0]);
+ pr_debug("unknown inbound packet %s\n", pptp_msg_name(msg));
fallthrough;
case PPTP_START_SESSION_REQUEST:
case PPTP_START_SESSION_REPLY:
diff --git a/net/netfilter/nf_conntrack_pptp.c b/net/netfilter/nf_conntrack_pptp.c
index a971183f11af..7ad247784cfa 100644
--- a/net/netfilter/nf_conntrack_pptp.c
+++ b/net/netfilter/nf_conntrack_pptp.c
@@ -72,24 +72,32 @@ EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn);
#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
/* PptpControlMessageType names */
-const char *const pptp_msg_name[] = {
- "UNKNOWN_MESSAGE",
- "START_SESSION_REQUEST",
- "START_SESSION_REPLY",
- "STOP_SESSION_REQUEST",
- "STOP_SESSION_REPLY",
- "ECHO_REQUEST",
- "ECHO_REPLY",
- "OUT_CALL_REQUEST",
- "OUT_CALL_REPLY",
- "IN_CALL_REQUEST",
- "IN_CALL_REPLY",
- "IN_CALL_CONNECT",
- "CALL_CLEAR_REQUEST",
- "CALL_DISCONNECT_NOTIFY",
- "WAN_ERROR_NOTIFY",
- "SET_LINK_INFO"
+static const char *const pptp_msg_name_array[PPTP_MSG_MAX + 1] = {
+ [0] = "UNKNOWN_MESSAGE",
+ [PPTP_START_SESSION_REQUEST] = "START_SESSION_REQUEST",
+ [PPTP_START_SESSION_REPLY] = "START_SESSION_REPLY",
+ [PPTP_STOP_SESSION_REQUEST] = "STOP_SESSION_REQUEST",
+ [PPTP_STOP_SESSION_REPLY] = "STOP_SESSION_REPLY",
+ [PPTP_ECHO_REQUEST] = "ECHO_REQUEST",
+ [PPTP_ECHO_REPLY] = "ECHO_REPLY",
+ [PPTP_OUT_CALL_REQUEST] = "OUT_CALL_REQUEST",
+ [PPTP_OUT_CALL_REPLY] = "OUT_CALL_REPLY",
+ [PPTP_IN_CALL_REQUEST] = "IN_CALL_REQUEST",
+ [PPTP_IN_CALL_REPLY] = "IN_CALL_REPLY",
+ [PPTP_IN_CALL_CONNECT] = "IN_CALL_CONNECT",
+ [PPTP_CALL_CLEAR_REQUEST] = "CALL_CLEAR_REQUEST",
+ [PPTP_CALL_DISCONNECT_NOTIFY] = "CALL_DISCONNECT_NOTIFY",
+ [PPTP_WAN_ERROR_NOTIFY] = "WAN_ERROR_NOTIFY",
+ [PPTP_SET_LINK_INFO] = "SET_LINK_INFO"
};
+
+const char *const pptp_msg_name(u_int16_t msg)
+{
+ if (msg > PPTP_MSG_MAX)
+ return pptp_msg_name_array[0];
+
+ return pptp_msg_name_array[msg];
+}
EXPORT_SYMBOL(pptp_msg_name);
#endif
@@ -276,7 +284,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
typeof(nf_nat_pptp_hook_inbound) nf_nat_pptp_inbound;
msg = ntohs(ctlh->messageType);
- pr_debug("inbound control message %s\n", pptp_msg_name[msg]);
+ pr_debug("inbound control message %s\n", pptp_msg_name(msg));
switch (msg) {
case PPTP_START_SESSION_REPLY:
@@ -311,7 +319,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
pcid = pptpReq->ocack.peersCallID;
if (info->pns_call_id != pcid)
goto invalid;
- pr_debug("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg],
+ pr_debug("%s, CID=%X, PCID=%X\n", pptp_msg_name(msg),
ntohs(cid), ntohs(pcid));
if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) {
@@ -328,7 +336,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
goto invalid;
cid = pptpReq->icreq.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
+ pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
info->cstate = PPTP_CALL_IN_REQ;
info->pac_call_id = cid;
break;
@@ -347,7 +355,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
if (info->pns_call_id != pcid)
goto invalid;
- pr_debug("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(pcid));
+ pr_debug("%s, PCID=%X\n", pptp_msg_name(msg), ntohs(pcid));
info->cstate = PPTP_CALL_IN_CONF;
/* we expect a GRE connection from PAC to PNS */
@@ -357,7 +365,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
case PPTP_CALL_DISCONNECT_NOTIFY:
/* server confirms disconnect */
cid = pptpReq->disc.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
+ pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
info->cstate = PPTP_CALL_NONE;
/* untrack this call id, unexpect GRE packets */
@@ -384,7 +392,7 @@ pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
invalid:
pr_debug("invalid %s: type=%d cid=%u pcid=%u "
"cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
- msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
+ pptp_msg_name(msg),
msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
ntohs(info->pns_call_id), ntohs(info->pac_call_id));
return NF_ACCEPT;
@@ -404,7 +412,7 @@ pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
typeof(nf_nat_pptp_hook_outbound) nf_nat_pptp_outbound;
msg = ntohs(ctlh->messageType);
- pr_debug("outbound control message %s\n", pptp_msg_name[msg]);
+ pr_debug("outbound control message %s\n", pptp_msg_name(msg));
switch (msg) {
case PPTP_START_SESSION_REQUEST:
@@ -426,7 +434,7 @@ pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
info->cstate = PPTP_CALL_OUT_REQ;
/* track PNS call id */
cid = pptpReq->ocreq.callID;
- pr_debug("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
+ pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
info->pns_call_id = cid;
break;
@@ -440,7 +448,7 @@ pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
pcid = pptpReq->icack.peersCallID;
if (info->pac_call_id != pcid)
goto invalid;
- pr_debug("%s, CID=%X PCID=%X\n", pptp_msg_name[msg],
+ pr_debug("%s, CID=%X PCID=%X\n", pptp_msg_name(msg),
ntohs(cid), ntohs(pcid));
if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) {
@@ -480,7 +488,7 @@ pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
invalid:
pr_debug("invalid %s: type=%d cid=%u pcid=%u "
"cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
- msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
+ pptp_msg_name(msg),
msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
ntohs(info->pns_call_id), ntohs(info->pac_call_id));
return NF_ACCEPT;