[PATCH] phonet: fix building with clang

From: Arnd Bergmann
Date: Tue Feb 19 2019 - 16:54:20 EST


clang warns about overflowing the data[] member in the struct pnpipehdr:

net/phonet/pep.c:295:8: warning: array index 4 is past the end of the array (which contains 1 element) [-Warray-bounds]
if (hdr->data[4] == PEP_IND_READY)
^ ~
include/net/phonet/pep.h:66:3: note: array 'data' declared here
u8 data[1];

Using a flexible array member at the end of the struct avoids the
warning, but since we cannot have a flexible array member inside
of the union, each index now has to be moved back by one, which
makes it a little uglier.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
include/net/phonet/pep.h | 5 +++--
net/phonet/pep.c | 32 ++++++++++++++++----------------
2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/include/net/phonet/pep.h b/include/net/phonet/pep.h
index b669fe6dbc3b..98f31c7ea23d 100644
--- a/include/net/phonet/pep.h
+++ b/include/net/phonet/pep.h
@@ -63,10 +63,11 @@ struct pnpipehdr {
u8 state_after_reset; /* reset request */
u8 error_code; /* any response */
u8 pep_type; /* status indication */
- u8 data[1];
+ u8 data0; /* anything else */
};
+ u8 data[];
};
-#define other_pep_type data[1]
+#define other_pep_type data[0]

static inline struct pnpipehdr *pnp_hdr(struct sk_buff *skb)
{
diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index 9fc76b19cd3c..db3473540303 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -132,7 +132,7 @@ static int pep_indicate(struct sock *sk, u8 id, u8 code,
ph->utid = 0;
ph->message_id = id;
ph->pipe_handle = pn->pipe_handle;
- ph->data[0] = code;
+ ph->error_code = code;
return pn_skb_send(sk, skb, NULL);
}

@@ -153,7 +153,7 @@ static int pipe_handler_request(struct sock *sk, u8 id, u8 code,
ph->utid = id; /* whatever */
ph->message_id = id;
ph->pipe_handle = pn->pipe_handle;
- ph->data[0] = code;
+ ph->error_code = code;
return pn_skb_send(sk, skb, NULL);
}

@@ -208,7 +208,7 @@ static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code,
struct pnpipehdr *ph;
struct sockaddr_pn dst;
u8 data[4] = {
- oph->data[0], /* PEP type */
+ oph->pep_type, /* PEP type */
code, /* error code, at an unusual offset */
PAD, PAD,
};
@@ -221,7 +221,7 @@ static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code,
ph->utid = oph->utid;
ph->message_id = PNS_PEP_CTRL_RESP;
ph->pipe_handle = oph->pipe_handle;
- ph->data[0] = oph->data[1]; /* CTRL id */
+ ph->data0 = oph->data[0]; /* CTRL id */

pn_skb_get_src_sockaddr(oskb, &dst);
return pn_skb_send(sk, skb, &dst);
@@ -272,17 +272,17 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
return -EINVAL;

hdr = pnp_hdr(skb);
- if (hdr->data[0] != PN_PEP_TYPE_COMMON) {
+ if (hdr->pep_type != PN_PEP_TYPE_COMMON) {
net_dbg_ratelimited("Phonet unknown PEP type: %u\n",
- (unsigned int)hdr->data[0]);
+ (unsigned int)hdr->pep_type);
return -EOPNOTSUPP;
}

- switch (hdr->data[1]) {
+ switch (hdr->data[0]) {
case PN_PEP_IND_FLOW_CONTROL:
switch (pn->tx_fc) {
case PN_LEGACY_FLOW_CONTROL:
- switch (hdr->data[4]) {
+ switch (hdr->data[3]) {
case PEP_IND_BUSY:
atomic_set(&pn->tx_credits, 0);
break;
@@ -292,7 +292,7 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
}
break;
case PN_ONE_CREDIT_FLOW_CONTROL:
- if (hdr->data[4] == PEP_IND_READY)
+ if (hdr->data[3] == PEP_IND_READY)
atomic_set(&pn->tx_credits, wake = 1);
break;
}
@@ -301,12 +301,12 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:
if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)
break;
- atomic_add(wake = hdr->data[4], &pn->tx_credits);
+ atomic_add(wake = hdr->data[3], &pn->tx_credits);
break;

default:
net_dbg_ratelimited("Phonet unknown PEP indication: %u\n",
- (unsigned int)hdr->data[1]);
+ (unsigned int)hdr->data[0]);
return -EOPNOTSUPP;
}
if (wake)
@@ -318,7 +318,7 @@ static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr = pnp_hdr(skb);
- u8 n_sb = hdr->data[0];
+ u8 n_sb = hdr->data0;

pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
__skb_pull(skb, sizeof(*hdr));
@@ -506,7 +506,7 @@ static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb)
return -ECONNREFUSED;

/* Parse sub-blocks */
- n_sb = hdr->data[4];
+ n_sb = hdr->data[3];
while (n_sb > 0) {
u8 type, buf[6], len = sizeof(buf);
const u8 *data = pep_get_sb(skb, &type, &len, buf);
@@ -739,7 +739,7 @@ static int pipe_do_remove(struct sock *sk)
ph->utid = 0;
ph->message_id = PNS_PIPE_REMOVE_REQ;
ph->pipe_handle = pn->pipe_handle;
- ph->data[0] = PAD;
+ ph->data0 = PAD;
return pn_skb_send(sk, skb, NULL);
}

@@ -817,7 +817,7 @@ static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp,
peer_type = hdr->other_pep_type << 8;

/* Parse sub-blocks (options) */
- n_sb = hdr->data[4];
+ n_sb = hdr->data[3];
while (n_sb > 0) {
u8 type, buf[1], len = sizeof(buf);
const u8 *data = pep_get_sb(skb, &type, &len, buf);
@@ -1109,7 +1109,7 @@ static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
ph->utid = 0;
if (pn->aligned) {
ph->message_id = PNS_PIPE_ALIGNED_DATA;
- ph->data[0] = 0; /* padding */
+ ph->data0 = 0; /* padding */
} else
ph->message_id = PNS_PIPE_DATA;
ph->pipe_handle = pn->pipe_handle;
--
2.20.0