From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
This patch reworks the compatibility infrastructure to place the private
match and target information in the contiguous area just after the nft_expr
header.
The compatibility infrastructure registers a native operation that
maps to one of the existing matches/targets. This allows no modification
in the layout of the nft_expr to include any new size field.
Original idea from Patrick McHardy.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/net/netfilter/nf_tables.h | 5 +-
net/netfilter/nf_tables_api.c | 11 +-
net/netfilter/nft_cmp.c | 3 +-
net/netfilter/nft_compat.c | 279 +++++++++++++++++++++----------------
net/netfilter/nft_payload.c | 3 +-
5 files changed, 172 insertions(+), 129 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index e7dc1da..26d75e4 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -238,7 +238,8 @@ extern void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
* @maxattr: highest netlink attribute number
*/
struct nft_expr_type {
- const struct nft_expr_ops *(*select_ops)(const struct nlattr * const tb[]);
+ const struct nft_expr_ops *(*select_ops)(const struct nft_ctx *,
+ const struct nlattr * const tb[]);
const struct nft_expr_ops *ops;
struct list_head list;
const char *name;
@@ -256,6 +257,7 @@ struct nft_expr_type {
* @destroy: destruction function
* @dump: function to dump parameters
* @type: expression type
+ * @data: extra data to attach to this expression operation
*/
struct nft_expr;
struct nft_expr_ops {
@@ -272,6 +274,7 @@ struct nft_expr_ops {
const struct nft_expr *expr);
const struct nft_data * (*get_verdict)(const struct nft_expr *expr);
const struct nft_expr_type *type;
+ void *data;
};
#define NFT_EXPR_MAXATTR 16
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a847375..67b4548 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1026,7 +1026,8 @@ struct nft_expr_info {
struct nlattr *tb[NFT_EXPR_MAXATTR + 1];
};
-static int nf_tables_expr_parse(const struct nlattr *nla,
+static int nf_tables_expr_parse(const struct nft_ctx *ctx,
+ const struct nlattr *nla,
struct nft_expr_info *info)
{
const struct nft_expr_type *type;
@@ -1051,7 +1052,8 @@ static int nf_tables_expr_parse(const struct nlattr *nla,
memset(info->tb, 0, sizeof(info->tb[0]) * (type->maxattr + 1));
if (type->select_ops != NULL) {
- ops = type->select_ops((const struct nlattr * const *)info->tb);
+ ops = type->select_ops(ctx,
+ (const struct nlattr * const *)info->tb);
if (IS_ERR(ops)) {
err = PTR_ERR(ops);
goto err1;
@@ -1385,6 +1387,8 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
handle = nf_tables_alloc_handle(table);
}
+ nft_ctx_init(&ctx, skb, nlh, afi, table, chain);
+
n = 0;
size = 0;
if (nla[NFTA_RULE_EXPRESSIONS]) {
@@ -1394,7 +1398,7 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
goto err1;
if (n == NFT_RULE_MAXEXPRS)
goto err1;
- err = nf_tables_expr_parse(tmp, &info[n]);
+ err = nf_tables_expr_parse(&ctx, tmp, &info[n]);
if (err < 0)
goto err1;
size += info[n].ops->size;
@@ -1410,7 +1414,6 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
rule->handle = handle;
rule->dlen = size;
- nft_ctx_init(&ctx, skb, nlh, afi, table, chain);
expr = nft_expr_first(rule);
for (i = 0; i < n; i++) {
err = nf_tables_newexpr(&ctx, &info[i], expr);
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index 37134f3..954925d 100644
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -162,7 +162,8 @@ const struct nft_expr_ops nft_cmp_fast_ops = {
.dump = nft_cmp_fast_dump,
};
-static const struct nft_expr_ops *nft_cmp_select_ops(const struct nlattr * const tb[])
+static const struct nft_expr_ops *
+nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
{
struct nft_data_desc desc;
struct nft_data data;
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index b4a3ad3..91f827b 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -66,34 +66,27 @@ nft_compat_set_par(struct xt_action_param *par, const struct nft_pktinfo *pkt,
par->fragoff = pkt->fragoff;
}
-struct nft_target {
- struct xt_target *target;
- __u32 family;
- __u32 info_len;
- void *info;
-};
-
static void nft_target_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
- const struct nft_target *priv = nft_expr_priv(expr);
+ void *info = nft_expr_priv(expr);
+ struct xt_target *target = expr->ops->data;
struct sk_buff *skb = pkt->skb;
struct xt_action_param par;
int ret;
if (!pkt->compat_set) {
if (nft_compat_set_pktinfo((struct nft_pktinfo *)pkt,
- priv->family) < 0) {
+ target->family) < 0) {
data[NFT_REG_VERDICT].verdict = NF_DROP;
return;
}
}
- nft_compat_set_par(&par, pkt, priv->target, priv->info,
- priv->family);
+ nft_compat_set_par(&par, pkt, target, info, target->family);
- ret = priv->target->target(skb, &par);
+ ret = target->target(skb, &par);
if (par.hotdrop)
ret = NF_DROP;
@@ -117,13 +110,14 @@ static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
static void
nft_target_set_tgchk_param(struct xt_tgchk_param *par,
- const struct nft_ctx *ctx, struct nft_target *priv)
+ const struct nft_ctx *ctx,
+ struct xt_target *target, void *info)
{
par->net = &init_net;
par->table = ctx->table->name;
par->entryinfo = NULL; /* FIXME */
- par->target = priv->target;
- par->targinfo = priv->info;
+ par->target = target;
+ par->targinfo = info;
par->hook_mask = 0; /* FIXME */
par->family = ctx->afi->family;
}
@@ -132,71 +126,50 @@ static int
nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
- struct nft_target *priv = nft_expr_priv(expr);
+ void *info = nft_expr_priv(expr);
+ struct xt_target *target = expr->ops->data;
struct xt_tgchk_param par;
- const char *tg_name;
- __u32 rev;
+ size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
int ret;
- if (tb[NFTA_TARGET_NAME] == NULL ||
- tb[NFTA_TARGET_REV] == NULL ||
- tb[NFTA_TARGET_INFO] == NULL)
- return -EINVAL;
-
- tg_name = nla_data(tb[NFTA_TARGET_NAME]);
- rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
- priv->family = ctx->afi->family;
-
- priv->target = xt_request_find_target(priv->family, tg_name, rev);
- if (IS_ERR(priv->target))
- return PTR_ERR(priv->target);
-
- priv->info_len = nla_len(tb[NFTA_TARGET_INFO]);
- if (priv->info_len == 0)
- return -EINVAL;
-
- priv->info = kzalloc(priv->info_len, GFP_ATOMIC);
- if (priv->info == NULL)
- return -ENOMEM;
+ memcpy(info, nla_data(tb[NFTA_TARGET_INFO]),
+ XT_ALIGN(target->targetsize));
- memcpy(priv->info, nla_data(tb[NFTA_TARGET_INFO]), priv->info_len);
-
- nft_target_set_tgchk_param(&par, ctx, priv);
+ nft_target_set_tgchk_param(&par, ctx, target, info);
/* FIXME: not checking protocol and inversion */
- ret = xt_check_target(&par, priv->info_len, 0, false);
+ ret = xt_check_target(&par, size, 0, false);
if (ret < 0)
goto err;
/* The standard target cannot be used */
- if (priv->target->target == NULL) {
+ if (target->target == NULL) {
ret = -EINVAL;
goto err;
}
return 0;
err:
- kfree(priv->info);
- module_put(priv->target->me);
+ module_put(target->me);
return ret;
}
static void
nft_target_destroy(const struct nft_expr *expr)
{
- struct nft_target *priv = nft_expr_priv(expr);
+ struct xt_target *target = expr->ops->data;
- module_put(priv->target->me);
- kfree(priv->info);
+ module_put(target->me);
}
static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
- const struct nft_target *priv = nft_expr_priv(expr);
+ const struct xt_target *target = expr->ops->data;
+ void *info = nft_expr_priv(expr);
- if (nla_put_string(skb, NFTA_TARGET_NAME, priv->target->name) ||
- nla_put_be32(skb, NFTA_TARGET_REV, htonl(priv->target->revision)) ||
- nla_put(skb, NFTA_TARGET_INFO, priv->info_len, priv->info))
+ if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
+ nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
+ nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
goto nla_put_failure;
return 0;
@@ -205,34 +178,27 @@ nla_put_failure:
return -1;
}
-struct nft_match {
- struct xt_match *match;
- __u32 family;
- __u32 info_len;
- void *info;
-};
-
static void nft_match_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
- const struct nft_match *priv = nft_expr_priv(expr);
+ void *info = nft_expr_priv(expr);
+ struct xt_match *match = expr->ops->data;
struct sk_buff *skb = pkt->skb;
struct xt_action_param par;
bool ret;
if (!pkt->compat_set) {
if (nft_compat_set_pktinfo((struct nft_pktinfo *)pkt,
- priv->family) < 0) {
+ match->family) < 0) {
data[NFT_REG_VERDICT].verdict = NF_DROP;
return;
}
}
- nft_compat_set_par(&par, pkt, priv->match, priv->info,
- priv->family);
+ nft_compat_set_par(&par, pkt, match, info, match->family);
- ret = priv->match->match(skb, &par);
+ ret = match->match(skb, &par);
if (par.hotdrop) {
data[NFT_REG_VERDICT].verdict = NF_DROP;
@@ -257,14 +223,14 @@ static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
/* struct xt_mtchk_param and xt_tgchk_param look very similar */
static void
-nft_match_set_mtchk_param(struct xt_mtchk_param *par,
- const struct nft_ctx *ctx, struct nft_match *priv)
+nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
+ struct xt_match *match, void *info)
{
par->net = &init_net;
par->table = ctx->table->name;
par->entryinfo = NULL; /* FIXME */
- par->match = priv->match;
- par->matchinfo = priv->info;
+ par->match = match;
+ par->matchinfo = info;
par->hook_mask = 0; /* FIXME */
par->family = ctx->afi->family;
}
@@ -273,65 +239,43 @@ static int
nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
- struct nft_match *priv = nft_expr_priv(expr);
+ void *info = nft_expr_priv(expr);
+ struct xt_match *match = expr->ops->data;
struct xt_mtchk_param par;
- const char *mt_name;
- __u32 rev;
+ size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
int ret;
- if (tb[NFTA_MATCH_NAME] == NULL ||
- tb[NFTA_MATCH_REV] == NULL ||
- tb[NFTA_MATCH_INFO] == NULL)
- return -EINVAL;
-
- mt_name = nla_data(tb[NFTA_MATCH_NAME]);
- rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
- priv->family = ctx->afi->family;
-
- priv->match = xt_request_find_match(priv->family, mt_name, rev);
- if (IS_ERR(priv->match))
- return PTR_ERR(priv->match);
-
- priv->info_len = nla_len(tb[NFTA_MATCH_INFO]);
- if (priv->info_len == 0)
- return -EINVAL;
-
- priv->info = kzalloc(priv->info_len, GFP_ATOMIC);
- if (priv->info == NULL)
- return -ENOMEM;
-
- memcpy(priv->info, nla_data(tb[NFTA_MATCH_INFO]), priv->info_len);
+ memcpy(info, nla_data(tb[NFTA_MATCH_INFO]), XT_ALIGN(match->matchsize));
- nft_match_set_mtchk_param(&par, ctx, priv);
+ nft_match_set_mtchk_param(&par, ctx, match, info);
/* FIXME: not checking protocol and inversion, do this in userspace */
- ret = xt_check_match(&par, priv->info_len, 0, false);
+ ret = xt_check_match(&par, size, 0, false);
if (ret < 0)
goto err;
return 0;
err:
- kfree(priv->info);
- module_put(priv->match->me);
+ module_put(match->me);
return ret;
}
static void
nft_match_destroy(const struct nft_expr *expr)
{
- struct nft_match *priv = nft_expr_priv(expr);
+ struct xt_match *match = expr->ops->data;
- module_put(priv->match->me);
- kfree(priv->info);
+ module_put(match->me);
}
static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
- const struct nft_match *priv = nft_expr_priv(expr);
+ void *info = nft_expr_priv(expr);
+ struct xt_match *match = expr->ops->data;
- if (nla_put_string(skb, NFTA_MATCH_NAME, priv->match->name) ||
- nla_put_be32(skb, NFTA_MATCH_REV, htonl(priv->match->revision)) ||
- nla_put(skb, NFTA_MATCH_INFO, priv->info_len, priv->info))
+ if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
+ nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
+ nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
goto nla_put_failure;
return 0;
@@ -458,37 +402,128 @@ static const struct nfnetlink_subsystem nfnl_compat_subsys = {
.cb = nfnl_nft_compat_cb,
};
-static struct nft_expr_type nft_match_type;
-static const struct nft_expr_ops nft_match_ops = {
- .type = &nft_match_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_match)),
- .eval = nft_match_eval,
- .init = nft_match_init,
- .destroy = nft_match_destroy,
- .dump = nft_match_dump,
+static LIST_HEAD(nft_match_list);
+
+struct nft_xt {
+ struct list_head head;
+ struct nft_expr_ops ops;
};
+static struct nft_expr_type nft_match_type;
+
+static const struct nft_expr_ops *
+nft_match_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
+{
+ struct nft_xt *nft_match;
+ struct xt_match *match;
+ char *mt_name;
+ __u32 rev, family;
+
+ if (tb[NFTA_MATCH_NAME] == NULL ||
+ tb[NFTA_MATCH_REV] == NULL ||
+ tb[NFTA_MATCH_INFO] == NULL)
+ return ERR_PTR(-EINVAL);
+
+ mt_name = nla_data(tb[NFTA_MATCH_NAME]);
+ rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
+ family = ctx->afi->family;
+
+ /* Re-use the existing match if it's already loaded. */
+ list_for_each_entry(nft_match, &nft_match_list, head) {
+ struct xt_match *match = nft_match->ops.data;
+
+ if (strcmp(match->name, mt_name) == 0 &&
+ match->revision == rev && match->family == family)
+ return &nft_match->ops;
+ }
+
+ match = xt_request_find_match(family, mt_name, rev);
+ if (IS_ERR(match))
+ return ERR_PTR(-ENOENT);
+
+ /* This is the first time we use this match, allocate operations */
+ nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
+ if (nft_match == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ nft_match->ops.type = &nft_match_type;
+ nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
+ nft_match->ops.eval = nft_match_eval;
+ nft_match->ops.init = nft_match_init;
+ nft_match->ops.destroy = nft_match_destroy;
+ nft_match->ops.dump = nft_match_dump;
+ nft_match->ops.data = match;
+
+ list_add(&nft_match->head, &nft_match_list);
+
+ return &nft_match->ops;
+}
+
static struct nft_expr_type nft_match_type __read_mostly = {
.name = "match",
- .ops = &nft_match_ops,
+ .select_ops = nft_match_select_ops,
.policy = nft_match_policy,
.maxattr = NFTA_MATCH_MAX,
.owner = THIS_MODULE,
};
+static LIST_HEAD(nft_target_list);
+
static struct nft_expr_type nft_target_type;
-static const struct nft_expr_ops nft_target_ops = {
- .type = &nft_target_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_target)),
- .eval = nft_target_eval,
- .init = nft_target_init,
- .destroy = nft_target_destroy,
- .dump = nft_target_dump,
-};
+
+static const struct nft_expr_ops *
+nft_target_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
+{
+ struct nft_xt *nft_target;
+ struct xt_target *target;
+ char *tg_name;
+ __u32 rev, family;
+
+ if (tb[NFTA_TARGET_NAME] == NULL ||
+ tb[NFTA_TARGET_REV] == NULL ||
+ tb[NFTA_TARGET_INFO] == NULL)
+ return ERR_PTR(-EINVAL);
+
+ tg_name = nla_data(tb[NFTA_TARGET_NAME]);
+ rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
+ family = ctx->afi->family;
+
+ /* Re-use the existing target if it's already loaded. */
+ list_for_each_entry(nft_target, &nft_match_list, head) {
+ struct xt_target *target = nft_target->ops.data;
+
+ if (strcmp(target->name, tg_name) == 0 &&
+ target->revision == rev && target->family == family)
+ return &nft_target->ops;
+ }
+
+ target = xt_request_find_target(family, tg_name, rev);
+ if (IS_ERR(target))
+ return ERR_PTR(-ENOENT);
+
+ /* This is the first time we use this target, allocate operations */
+ nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
+ if (nft_target == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ nft_target->ops.type = &nft_target_type;
+ nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
+ nft_target->ops.eval = nft_target_eval;
+ nft_target->ops.init = nft_target_init;
+ nft_target->ops.destroy = nft_target_destroy;
+ nft_target->ops.dump = nft_target_dump;
+ nft_target->ops.data = target;
+
+ list_add(&nft_target->head, &nft_target_list);
+
+ return &nft_target->ops;
+}
static struct nft_expr_type nft_target_type __read_mostly = {
.name = "target",
- .ops = &nft_target_ops,
+ .select_ops = nft_target_select_ops,
.policy = nft_target_policy,
.maxattr = NFTA_TARGET_MAX,
.owner = THIS_MODULE,
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 6c81078..028e4d8 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -107,7 +107,8 @@ const struct nft_expr_ops nft_payload_fast_ops = {
};
static const struct nft_expr_ops *
-nft_payload_select_ops(const struct nlattr * const tb[])
+nft_payload_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
{
enum nft_payload_bases base;
unsigned int offset, len;
--
1.7.10.4
--
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