5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gustavo A. R. Silva gustavo@embeddedor.com
[ Upstream commit 6daf14140129d30207ed6a0a69851fa6a3636bda ]
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99:
struct foo { int stuff; struct boo array[]; };
By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this change:
"Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1]
Lastly, fix checkpatch.pl warning WARNING: __aligned(size) is preferred over __attribute__((aligned(size))) in net/bridge/netfilter/ebtables.c
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva gustavo@embeddedor.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Stable-dep-of: 542ed8145e6f ("netfilter: nft_set_hash: unaligned atomic read on struct nft_set_ext") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/netfilter/ipset/ip_set.h | 2 +- include/linux/netfilter/x_tables.h | 8 ++++---- include/linux/netfilter_arp/arp_tables.h | 2 +- include/linux/netfilter_bridge/ebtables.h | 2 +- include/linux/netfilter_ipv4/ip_tables.h | 2 +- include/linux/netfilter_ipv6/ip6_tables.h | 2 +- include/net/netfilter/nf_conntrack_extend.h | 2 +- include/net/netfilter/nf_conntrack_timeout.h | 2 +- include/net/netfilter/nf_tables.h | 6 +++--- include/uapi/linux/netfilter_bridge/ebt_among.h | 2 +- net/bridge/netfilter/ebtables.c | 2 +- net/ipv4/netfilter/arp_tables.c | 4 ++-- net/ipv4/netfilter/ip_tables.c | 4 ++-- net/ipv6/netfilter/ip6_tables.c | 4 ++-- net/netfilter/ipset/ip_set_bitmap_ip.c | 2 +- net/netfilter/ipset/ip_set_bitmap_ipmac.c | 2 +- net/netfilter/ipset/ip_set_bitmap_port.c | 2 +- net/netfilter/ipset/ip_set_hash_gen.h | 4 ++-- net/netfilter/nfnetlink_acct.c | 2 +- net/netfilter/xt_hashlimit.c | 2 +- net/netfilter/xt_recent.c | 4 ++-- 21 files changed, 31 insertions(+), 31 deletions(-)
diff --git a/include/linux/netfilter/ipset/ip_set.h b/include/linux/netfilter/ipset/ip_set.h index 35342fb48866..ef6a9d082c2c 100644 --- a/include/linux/netfilter/ipset/ip_set.h +++ b/include/linux/netfilter/ipset/ip_set.h @@ -98,7 +98,7 @@ struct ip_set_counter {
struct ip_set_comment_rcu { struct rcu_head rcu; - char str[0]; + char str[]; };
struct ip_set_comment { diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 04e7f5630509..e66ef9bf6ff3 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -264,7 +264,7 @@ struct xt_table_info { unsigned int stacksize; void ***jumpstack;
- unsigned char entries[0] __aligned(8); + unsigned char entries[] __aligned(8); };
int xt_register_target(struct xt_target *target); @@ -464,7 +464,7 @@ struct compat_xt_entry_match { } kernel; u_int16_t match_size; } u; - unsigned char data[0]; + unsigned char data[]; };
struct compat_xt_entry_target { @@ -480,7 +480,7 @@ struct compat_xt_entry_target { } kernel; u_int16_t target_size; } u; - unsigned char data[0]; + unsigned char data[]; };
/* FIXME: this works only on 32 bit tasks @@ -494,7 +494,7 @@ struct compat_xt_counters { struct compat_xt_counters_info { char name[XT_TABLE_MAXNAMELEN]; compat_uint_t num_counters; - struct compat_xt_counters counters[0]; + struct compat_xt_counters counters[]; };
struct _compat_xt_align { diff --git a/include/linux/netfilter_arp/arp_tables.h b/include/linux/netfilter_arp/arp_tables.h index 6988cf9ffe3a..26a13294318c 100644 --- a/include/linux/netfilter_arp/arp_tables.h +++ b/include/linux/netfilter_arp/arp_tables.h @@ -68,7 +68,7 @@ struct compat_arpt_entry { __u16 next_offset; compat_uint_t comefrom; struct compat_xt_counters counters; - unsigned char elems[0]; + unsigned char elems[]; };
static inline struct xt_entry_target * diff --git a/include/linux/netfilter_bridge/ebtables.h b/include/linux/netfilter_bridge/ebtables.h index f0d846df3a42..a18fb73a2b77 100644 --- a/include/linux/netfilter_bridge/ebtables.h +++ b/include/linux/netfilter_bridge/ebtables.h @@ -85,7 +85,7 @@ struct ebt_table_info { /* room to maintain the stack used for jumping from and into udc */ struct ebt_chainstack **chainstack; char *entries; - struct ebt_counter counters[0] ____cacheline_aligned; + struct ebt_counter counters[] ____cacheline_aligned; };
struct ebt_table { diff --git a/include/linux/netfilter_ipv4/ip_tables.h b/include/linux/netfilter_ipv4/ip_tables.h index e9e1ed74cdf1..b394bd4f68a3 100644 --- a/include/linux/netfilter_ipv4/ip_tables.h +++ b/include/linux/netfilter_ipv4/ip_tables.h @@ -76,7 +76,7 @@ struct compat_ipt_entry { __u16 next_offset; compat_uint_t comefrom; struct compat_xt_counters counters; - unsigned char elems[0]; + unsigned char elems[]; };
/* Helper functions */ diff --git a/include/linux/netfilter_ipv6/ip6_tables.h b/include/linux/netfilter_ipv6/ip6_tables.h index 78ab959c4575..8225f7821a29 100644 --- a/include/linux/netfilter_ipv6/ip6_tables.h +++ b/include/linux/netfilter_ipv6/ip6_tables.h @@ -43,7 +43,7 @@ struct compat_ip6t_entry { __u16 next_offset; compat_uint_t comefrom; struct compat_xt_counters counters; - unsigned char elems[0]; + unsigned char elems[]; };
static inline struct xt_entry_target * diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index 112a6f40dfaf..d0e87120d2f4 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -46,7 +46,7 @@ struct nf_ct_ext { struct rcu_head rcu; u8 offset[NF_CT_EXT_NUM]; u8 len; - char data[0]; + char data[]; };
static inline bool __nf_ct_ext_exist(const struct nf_ct_ext *ext, u8 id) diff --git a/include/net/netfilter/nf_conntrack_timeout.h b/include/net/netfilter/nf_conntrack_timeout.h index 6dd72396f534..659b0ea25b4d 100644 --- a/include/net/netfilter/nf_conntrack_timeout.h +++ b/include/net/netfilter/nf_conntrack_timeout.h @@ -14,7 +14,7 @@ struct nf_ct_timeout { __u16 l3num; const struct nf_conntrack_l4proto *l4proto; - char data[0]; + char data[]; };
struct ctnl_timeout { diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 648aac42dfec..c50dee30a70c 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -226,7 +226,7 @@ int nft_parse_register_store(const struct nft_ctx *ctx, */ struct nft_userdata { u8 len; - unsigned char data[0]; + unsigned char data[]; };
/** @@ -578,7 +578,7 @@ struct nft_set_ext_tmpl { struct nft_set_ext { u8 genmask; u8 offset[NFT_SET_EXT_NUM]; - char data[0]; + char data[]; };
static inline void nft_set_ext_prepare(struct nft_set_ext_tmpl *tmpl) @@ -1357,7 +1357,7 @@ struct nft_trans { int msg_type; bool put_net; struct nft_ctx ctx; - char data[0]; + char data[]; };
struct nft_trans_rule { diff --git a/include/uapi/linux/netfilter_bridge/ebt_among.h b/include/uapi/linux/netfilter_bridge/ebt_among.h index 9acf757bc1f7..73b26a280c4f 100644 --- a/include/uapi/linux/netfilter_bridge/ebt_among.h +++ b/include/uapi/linux/netfilter_bridge/ebt_among.h @@ -40,7 +40,7 @@ struct ebt_mac_wormhash_tuple { struct ebt_mac_wormhash { int table[257]; int poolsize; - struct ebt_mac_wormhash_tuple pool[0]; + struct ebt_mac_wormhash_tuple pool[]; };
#define ebt_mac_wormhash_size(x) ((x) ? sizeof(struct ebt_mac_wormhash) \ diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index f6853fc0fcc0..9d07cf277759 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1581,7 +1581,7 @@ struct compat_ebt_entry_mwt { compat_uptr_t ptr; } u; compat_uint_t match_size; - compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace)))); + compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace)); };
/* account for possible padding between match_size and ->data */ diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index a6f2e5bf7045..c62c9713e7dd 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1057,7 +1057,7 @@ struct compat_arpt_replace { u32 underflow[NF_ARP_NUMHOOKS]; u32 num_counters; compat_uptr_t counters; - struct compat_arpt_entry entries[0]; + struct compat_arpt_entry entries[]; };
static inline void compat_release_entry(struct compat_arpt_entry *e) @@ -1385,7 +1385,7 @@ static int compat_copy_entries_to_user(unsigned int total_size, struct compat_arpt_get_entries { char name[XT_TABLE_MAXNAMELEN]; compat_uint_t size; - struct compat_arpt_entry entrytable[0]; + struct compat_arpt_entry entrytable[]; };
static int compat_get_entries(struct net *net, diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 0076449eea35..c21ba5e62fff 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1211,7 +1211,7 @@ struct compat_ipt_replace { u32 underflow[NF_INET_NUMHOOKS]; u32 num_counters; compat_uptr_t counters; /* struct xt_counters * */ - struct compat_ipt_entry entries[0]; + struct compat_ipt_entry entries[]; };
static int @@ -1564,7 +1564,7 @@ compat_do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, struct compat_ipt_get_entries { char name[XT_TABLE_MAXNAMELEN]; compat_uint_t size; - struct compat_ipt_entry entrytable[0]; + struct compat_ipt_entry entrytable[]; };
static int diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 41268612bdd4..010a70402828 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1228,7 +1228,7 @@ struct compat_ip6t_replace { u32 underflow[NF_INET_NUMHOOKS]; u32 num_counters; compat_uptr_t counters; /* struct xt_counters * */ - struct compat_ip6t_entry entries[0]; + struct compat_ip6t_entry entries[]; };
static int @@ -1574,7 +1574,7 @@ compat_do_ip6t_set_ctl(struct sock *sk, int cmd, void __user *user, struct compat_ip6t_get_entries { char name[XT_TABLE_MAXNAMELEN]; compat_uint_t size; - struct compat_ip6t_entry entrytable[0]; + struct compat_ip6t_entry entrytable[]; };
static int diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c index e758b8120020..8fb170c7327f 100644 --- a/net/netfilter/ipset/ip_set_bitmap_ip.c +++ b/net/netfilter/ipset/ip_set_bitmap_ip.c @@ -46,7 +46,7 @@ struct bitmap_ip { u8 netmask; /* subnet netmask */ struct timer_list gc; /* garbage collection */ struct ip_set *set; /* attached to this ip_set */ - unsigned char extensions[0] /* data extensions */ + unsigned char extensions[] /* data extensions */ __aligned(__alignof__(u64)); };
diff --git a/net/netfilter/ipset/ip_set_bitmap_ipmac.c b/net/netfilter/ipset/ip_set_bitmap_ipmac.c index ae7cdc0d0f29..ebbcb9a16fe9 100644 --- a/net/netfilter/ipset/ip_set_bitmap_ipmac.c +++ b/net/netfilter/ipset/ip_set_bitmap_ipmac.c @@ -49,7 +49,7 @@ struct bitmap_ipmac { size_t memsize; /* members size */ struct timer_list gc; /* garbage collector */ struct ip_set *set; /* attached to this ip_set */ - unsigned char extensions[0] /* MAC + data extensions */ + unsigned char extensions[] /* MAC + data extensions */ __aligned(__alignof__(u64)); };
diff --git a/net/netfilter/ipset/ip_set_bitmap_port.c b/net/netfilter/ipset/ip_set_bitmap_port.c index d4a14750f5c4..1993f2783774 100644 --- a/net/netfilter/ipset/ip_set_bitmap_port.c +++ b/net/netfilter/ipset/ip_set_bitmap_port.c @@ -37,7 +37,7 @@ struct bitmap_port { size_t memsize; /* members size */ struct timer_list gc; /* garbage collection */ struct ip_set *set; /* attached to this ip_set */ - unsigned char extensions[0] /* data extensions */ + unsigned char extensions[] /* data extensions */ __aligned(__alignof__(u64)); };
diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h index 4346cae25a4a..30b8b3fad150 100644 --- a/net/netfilter/ipset/ip_set_hash_gen.h +++ b/net/netfilter/ipset/ip_set_hash_gen.h @@ -76,7 +76,7 @@ struct hbucket { DECLARE_BITMAP(used, AHASH_MAX_TUNED); u8 size; /* size of the array */ u8 pos; /* position of the first free entry */ - unsigned char value[0] /* the array of the values */ + unsigned char value[] /* the array of the values */ __aligned(__alignof__(u64)); };
@@ -109,7 +109,7 @@ struct htable { u8 htable_bits; /* size of hash table == 2^htable_bits */ u32 maxelem; /* Maxelem per region */ struct ip_set_region *hregion; /* Region locks and ext sizes */ - struct hbucket __rcu *bucket[0]; /* hashtable buckets */ + struct hbucket __rcu *bucket[]; /* hashtable buckets */ };
#define hbucket(h, i) ((h)->bucket[i]) diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c index 4b46421c5e17..ed4bde3c8850 100644 --- a/net/netfilter/nfnetlink_acct.c +++ b/net/netfilter/nfnetlink_acct.c @@ -33,7 +33,7 @@ struct nf_acct { refcount_t refcnt; char name[NFACCT_NAME_MAX]; struct rcu_head rcu_head; - char data[0]; + char data[]; };
struct nfacct_filter { diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 8c835ad63729..9c5cfd74a0ee 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -132,7 +132,7 @@ struct xt_hashlimit_htable { const char *name; struct net *net;
- struct hlist_head hash[0]; /* hashtable itself */ + struct hlist_head hash[]; /* hashtable itself */ };
static int diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 6fc0deb11aff..dae284e0ed15 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -71,7 +71,7 @@ struct recent_entry { u_int8_t ttl; u_int8_t index; u_int16_t nstamps; - unsigned long stamps[0]; + unsigned long stamps[]; };
struct recent_table { @@ -82,7 +82,7 @@ struct recent_table { unsigned int entries; u8 nstamps_max_mask; struct list_head lru_list; - struct list_head iphash[0]; + struct list_head iphash[]; };
struct recent_net {