From: Pablo Neira Ayuso pablo@netfilter.org
commit 4c559f15efcc43b996f4da528cd7f9483aaca36d upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/linux/netfilter/nf_conntrack_pptp.h | 2 net/ipv4/netfilter/nf_nat_pptp.c | 7 --- net/netfilter/nf_conntrack_pptp.c | 62 +++++++++++++++------------- 3 files changed, 38 insertions(+), 33 deletions(-)
--- a/include/linux/netfilter/nf_conntrack_pptp.h +++ b/include/linux/netfilter/nf_conntrack_pptp.h @@ -10,7 +10,7 @@ #include <net/netfilter/nf_conntrack_expect.h> #include <uapi/linux/netfilter/nf_conntrack_tuple_common.h>
-extern const char *const pptp_msg_name[]; +extern const char *const pptp_msg_name(u_int16_t msg);
/* state of the control session */ enum pptp_ctrlsess_state { --- 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)); /* fall through */ 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)); /* fall through */ case PPTP_START_SESSION_REQUEST: case PPTP_START_SESSION_REPLY: --- 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_expec
#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, un 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, un 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, un 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, un 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, un 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, un 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, u 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, u 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, u 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, u 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;