[PATCH 3.16 174/306] netfilter: nf_tables: fix type mismatch with error return from nft_parse_u32_check

[Ben Hutchings]

3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: "John W. Linville" <linville@xxxxxxxxxxxxx>

commit f1d505bb762e30bf316ff5d3b604914649d6aed3 upstream.

Commit 36b701fae12ac ("netfilter: nf_tables: validate maximum value of
u32 netlink attributes") introduced nft_parse_u32_check with a return
value of "unsigned int", yet on error it returns "-ERANGE".

This patch corrects the mismatch by changing the return value to "int",
which happens to match the actual users of nft_parse_u32_check already.

Found by Coverity, CID 1373930.

Note that commit 21a9e0f1568ea ("netfilter: nft_exthdr: fix error
handling in nft_exthdr_init()) attempted to address the issue, but
did not address the return type of nft_parse_u32_check.

Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Cc: Laura Garcia Liebana <nevola@xxxxxxxxx>
Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Fixes: 36b701fae12ac ("netfilter: nf_tables: validate maximum value...")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 include/net/netfilter/nf_tables.h | 2 +-
 net/netfilter/nf_tables_api.c     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -113,7 +113,7 @@ static inline enum nft_registers nft_typ
 	return type == NFT_DATA_VERDICT ? NFT_REG_VERDICT : NFT_REG_1;
 }
 
-unsigned int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest);
+int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest);
 int nft_validate_input_register(enum nft_registers reg);
 int nft_validate_output_register(enum nft_registers reg);
 int nft_validate_data_load(const struct nft_ctx *ctx, enum nft_registers reg,
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3723,7 +3723,7 @@ static int nf_tables_check_loops(const s
  *	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 nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest)
 {
 	u32 val;