From: Laura Garcia Liebana <nev...@gmail.com>
Fetch value and validate u32 netlink attribute. This validation is
usually required when the u32 netlink attributes are being stored in a
field whose size is smaller.
This patch revisits 4da449ae1df9 ("netfilter: nft_exthdr: Add size check
on u8 nft_exthdr attributes").
Fixes: 96518518cc41 ("netfilter: add nftables")
Suggested-by: Pablo Neira Ayuso <pa...@netfilter.org>
Signed-off-by: Laura Garcia Liebana <nev...@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
include/net/netfilter/nf_tables.h | 1 +
net/netfilter/nf_tables_api.c | 25 +++++++++++++++++++++++++
net/netfilter/nft_bitwise.c | 8 +++++++-
net/netfilter/nft_byteorder.c | 15 +++++++++++++--
net/netfilter/nft_cmp.c | 3 +++
net/netfilter/nft_exthdr.c | 12 +++++++-----
net/netfilter/nft_immediate.c | 4 ++++
7 files changed, 60 insertions(+), 8 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h
b/include/net/netfilter/nf_tables.h
index a7a7cebc8d07..5031e072567b 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -145,6 +145,7 @@ static inline enum nft_registers nft_type_to_reg(enum
nft_data_types type)
return type == NFT_DATA_VERDICT ? NFT_REG_VERDICT : NFT_REG_1 *
NFT_REG_SIZE / NFT_REG32_SIZE;
}
+unsigned int nft_parse_u32_check(const struct nlattr *attr, int max, u32
*dest);
unsigned int nft_parse_register(const struct nlattr *attr);
int nft_dump_register(struct sk_buff *skb, unsigned int attr, unsigned int
reg);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index bd9715e5ff26..b70d3ea1430e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4410,6 +4410,31 @@ static int nf_tables_check_loops(const struct nft_ctx
*ctx,
}
/**
+ * nft_parse_u32_check - fetch u32 attribute and check for maximum value
+ *
+ * @attr: netlink attribute to fetch value from
+ * @max: maximum value to be stored in dest
+ * @dest: pointer to the variable
+ *
+ * Parse, check and store a given u32 netlink attribute into variable.
+ * This function returns -ERANGE if the value goes over maximum value.
+ * Otherwise a 0 is returned and the attribute value is stored in the
+ * destination variable.
+ */
+unsigned int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest)
+{
+ int val;
+
+ val = ntohl(nla_get_be32(attr));
+ if (val > max)
+ return -ERANGE;
+
+ *dest = val;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nft_parse_u32_check);
+
+/**
* nft_parse_register - parse a register value from a netlink attribute
*
* @attr: netlink attribute
diff --git a/net/netfilter/nft_bitwise.c b/net/netfilter/nft_bitwise.c
index d71cc18fa35d..31c15ed2e5fc 100644
--- a/net/netfilter/nft_bitwise.c
+++ b/net/netfilter/nft_bitwise.c
@@ -52,6 +52,7 @@ static int nft_bitwise_init(const struct nft_ctx *ctx,
{
struct nft_bitwise *priv = nft_expr_priv(expr);
struct nft_data_desc d1, d2;
+ u32 len;
int err;
if (tb[NFTA_BITWISE_SREG] == NULL ||
@@ -61,7 +62,12 @@ static int nft_bitwise_init(const struct nft_ctx *ctx,
tb[NFTA_BITWISE_XOR] == NULL)
return -EINVAL;
- priv->len = ntohl(nla_get_be32(tb[NFTA_BITWISE_LEN]));
+ err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
+ if (err < 0)
+ return err;
+
+ priv->len = len;
+
priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
err = nft_validate_register_load(priv->sreg, priv->len);
if (err < 0)
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index b78c28ba465f..ee63d981268d 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -99,6 +99,7 @@ static int nft_byteorder_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_byteorder *priv = nft_expr_priv(expr);
+ u32 size, len;
int err;
if (tb[NFTA_BYTEORDER_SREG] == NULL ||
@@ -117,7 +118,12 @@ static int nft_byteorder_init(const struct nft_ctx *ctx,
return -EINVAL;
}
- priv->size = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_SIZE]));
+ err = nft_parse_u32_check(tb[NFTA_BYTEORDER_SIZE], U8_MAX, &size);
+ if (err < 0)
+ return err;
+
+ priv->size = size;
+
switch (priv->size) {
case 2:
case 4:
@@ -128,7 +134,12 @@ static int nft_byteorder_init(const struct nft_ctx *ctx,
}
priv->sreg = nft_parse_register(tb[NFTA_BYTEORDER_SREG]);
- priv->len = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_LEN]));
+ err = nft_parse_u32_check(tb[NFTA_BYTEORDER_LEN], U8_MAX, &len);
+ if (err < 0)
+ return err;
+
+ priv->len = len;
+
err = nft_validate_register_load(priv->sreg, priv->len);
if (err < 0)
return err;
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index e25b35d70e4d..2e53739812b1 100644
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -84,6 +84,9 @@ static int nft_cmp_init(const struct nft_ctx *ctx, const
struct nft_expr *expr,
if (err < 0)
return err;
+ if (desc.len > U8_MAX)
+ return -ERANGE;
+
priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
priv->len = desc.len;
return 0;
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 82c264e40278..a84cf3d66056 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -59,7 +59,7 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_exthdr *priv = nft_expr_priv(expr);
- u32 offset, len;
+ u32 offset, len, err;
if (tb[NFTA_EXTHDR_DREG] == NULL ||
tb[NFTA_EXTHDR_TYPE] == NULL ||
@@ -67,11 +67,13 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
tb[NFTA_EXTHDR_LEN] == NULL)
return -EINVAL;
- offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
- len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
+ err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
+ if (err < 0)
+ return err;
- if (offset > U8_MAX || len > U8_MAX)
- return -ERANGE;
+ err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
+ if (err < 0)
+ return err;
priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
priv->offset = offset;
diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index db3b746858e3..d17018ff54e6 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -53,6 +53,10 @@ static int nft_immediate_init(const struct nft_ctx *ctx,
tb[NFTA_IMMEDIATE_DATA]);
if (err < 0)
return err;
+
+ if (desc.len > U8_MAX)
+ return -ERANGE;
+
priv->dlen = desc.len;
priv->dreg = nft_parse_register(tb[NFTA_IMMEDIATE_DREG]);
--
2.1.4
