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netfilter: replace skb_make_writable with skb_ensure_writable 

This converts all remaining users and then removes skb_make_writable.

Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2019-05-23 15:44:12 +02:00 committed by Pablo Neira Ayuso
parent fb2eb1c131
commit 2cf6bffc49
5 changed files with 6 additions and 33 deletions
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5
include/linux/netfilter.h
View File

@ -336,11 +336,6 @@ int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
char __user *opt, int *len); char __user *opt, int *len);
#endif #endif
/* Call this before modifying an existing packet: ensures it is
modifiable and linear to the point you care about (writable_len).
Returns true or false. */
int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
struct flowi; struct flowi;
struct nf_queue_entry; struct nf_queue_entry;

22
net/netfilter/core.c
View File

@ -536,28 +536,6 @@ int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
} }
EXPORT_SYMBOL(nf_hook_slow); EXPORT_SYMBOL(nf_hook_slow);
int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
{
if (writable_len > skb->len)
return 0;
/* Not exclusive use of packet? Must copy. */
if (!skb_cloned(skb)) {
if (writable_len <= skb_headlen(skb))
return 1;
} else if (skb_clone_writable(skb, writable_len))
return 1;
if (writable_len <= skb_headlen(skb))
writable_len = 0;
else
writable_len -= skb_headlen(skb);
return !!__pskb_pull_tail(skb, writable_len);
}
EXPORT_SYMBOL(skb_make_writable);
/* This needs to be compiled in any case to avoid dependencies between the /* This needs to be compiled in any case to avoid dependencies between the
* nfnetlink_queue code and nf_conntrack. * nfnetlink_queue code and nf_conntrack.
*/ */

2
net/netfilter/nf_synproxy_core.c
View File

@ -196,7 +196,7 @@ unsigned int synproxy_tstamp_adjust(struct sk_buff *skb,
optoff = protoff + sizeof(struct tcphdr); optoff = protoff + sizeof(struct tcphdr);
optend = protoff + th->doff * 4; optend = protoff + th->doff * 4;
if (!skb_make_writable(skb, optend)) if (skb_ensure_writable(skb, optend))
return 0; return 0;
while (optoff < optend) { while (optoff < optend) {

2
net/netfilter/nfnetlink_queue.c
View File

@ -863,7 +863,7 @@ nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff)
} }
skb_put(e->skb, diff); skb_put(e->skb, diff);
} }
if (!skb_make_writable(e->skb, data_len)) if (skb_ensure_writable(e->skb, data_len))
return -ENOMEM; return -ENOMEM;
skb_copy_to_linear_data(e->skb, data, data_len); skb_copy_to_linear_data(e->skb, data, data_len);
e->skb->ip_summed = CHECKSUM_NONE; e->skb->ip_summed = CHECKSUM_NONE;

8
net/netfilter/xt_DSCP.c
View File

@ -34,7 +34,7 @@ dscp_tg(struct sk_buff *skb, const struct xt_action_param *par)
u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) { if (dscp != dinfo->dscp) {
if (!skb_make_writable(skb, sizeof(struct iphdr))) if (skb_ensure_writable(skb, sizeof(struct iphdr)))
return NF_DROP; return NF_DROP;
ipv4_change_dsfield(ip_hdr(skb), ipv4_change_dsfield(ip_hdr(skb),
@ -52,7 +52,7 @@ dscp_tg6(struct sk_buff *skb, const struct xt_action_param *par)
u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) { if (dscp != dinfo->dscp) {
if (!skb_make_writable(skb, sizeof(struct ipv6hdr))) if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
return NF_DROP; return NF_DROP;
ipv6_change_dsfield(ipv6_hdr(skb), ipv6_change_dsfield(ipv6_hdr(skb),
@ -82,7 +82,7 @@ tos_tg(struct sk_buff *skb, const struct xt_action_param *par)
nv = (orig & ~info->tos_mask) ^ info->tos_value; nv = (orig & ~info->tos_mask) ^ info->tos_value;
if (orig != nv) { if (orig != nv) {
if (!skb_make_writable(skb, sizeof(struct iphdr))) if (skb_ensure_writable(skb, sizeof(struct iphdr)))
return NF_DROP; return NF_DROP;
iph = ip_hdr(skb); iph = ip_hdr(skb);
ipv4_change_dsfield(iph, 0, nv); ipv4_change_dsfield(iph, 0, nv);
@ -102,7 +102,7 @@ tos_tg6(struct sk_buff *skb, const struct xt_action_param *par)
nv = (orig & ~info->tos_mask) ^ info->tos_value; nv = (orig & ~info->tos_mask) ^ info->tos_value;
if (orig != nv) { if (orig != nv) {
if (!skb_make_writable(skb, sizeof(struct iphdr))) if (skb_ensure_writable(skb, sizeof(struct iphdr)))
return NF_DROP; return NF_DROP;
iph = ipv6_hdr(skb); iph = ipv6_hdr(skb);
ipv6_change_dsfield(iph, 0, nv); ipv6_change_dsfield(iph, 0, nv);