Commit aba36930 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller

net: always initialize pagedlen

In ip packet generation, pagedlen is initialized for each skb at the
start of the loop in __ip(6)_append_data, before label alloc_new_skb.

Depending on compiler options, code can be generated that jumps to
this label, triggering use of an an uninitialized variable.

In practice, at -O2, the generated code moves the initialization below
the label. But the code should not rely on that for correctness.

Fixes: 15e36f5b ("udp: paged allocation with gso")
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9efdda4e
...@@ -939,7 +939,7 @@ static int __ip_append_data(struct sock *sk, ...@@ -939,7 +939,7 @@ static int __ip_append_data(struct sock *sk,
unsigned int fraglen; unsigned int fraglen;
unsigned int fraggap; unsigned int fraggap;
unsigned int alloclen; unsigned int alloclen;
unsigned int pagedlen = 0; unsigned int pagedlen;
struct sk_buff *skb_prev; struct sk_buff *skb_prev;
alloc_new_skb: alloc_new_skb:
skb_prev = skb; skb_prev = skb;
...@@ -956,6 +956,7 @@ static int __ip_append_data(struct sock *sk, ...@@ -956,6 +956,7 @@ static int __ip_append_data(struct sock *sk,
if (datalen > mtu - fragheaderlen) if (datalen > mtu - fragheaderlen)
datalen = maxfraglen - fragheaderlen; datalen = maxfraglen - fragheaderlen;
fraglen = datalen + fragheaderlen; fraglen = datalen + fragheaderlen;
pagedlen = 0;
if ((flags & MSG_MORE) && if ((flags & MSG_MORE) &&
!(rt->dst.dev->features&NETIF_F_SG)) !(rt->dst.dev->features&NETIF_F_SG))
......
...@@ -1354,7 +1354,7 @@ static int __ip6_append_data(struct sock *sk, ...@@ -1354,7 +1354,7 @@ static int __ip6_append_data(struct sock *sk,
unsigned int fraglen; unsigned int fraglen;
unsigned int fraggap; unsigned int fraggap;
unsigned int alloclen; unsigned int alloclen;
unsigned int pagedlen = 0; unsigned int pagedlen;
alloc_new_skb: alloc_new_skb:
/* There's no room in the current skb */ /* There's no room in the current skb */
if (skb) if (skb)
...@@ -1378,6 +1378,7 @@ static int __ip6_append_data(struct sock *sk, ...@@ -1378,6 +1378,7 @@ static int __ip6_append_data(struct sock *sk,
if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
fraglen = datalen + fragheaderlen; fraglen = datalen + fragheaderlen;
pagedlen = 0;
if ((flags & MSG_MORE) && if ((flags & MSG_MORE) &&
!(rt->dst.dev->features&NETIF_F_SG)) !(rt->dst.dev->features&NETIF_F_SG))
......
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