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authorEric Dumazet <edumazet@google.com>2015-03-11 18:53:14 -0700
committerDavid S. Miller <davem@davemloft.net>2015-03-11 21:55:28 -0400
commit33cf7c90fe2f97afb1cadaa0cfb782cb9d1b9ee2 (patch)
tree7a0c80d0b2bb618919d966ce5b827c7eb8f843f6 /net/core/sock_diag.c
parentfib_trie: Only display main table in /proc/net/route (diff)
downloadlinux-dev-33cf7c90fe2f97afb1cadaa0cfb782cb9d1b9ee2.tar.xz
linux-dev-33cf7c90fe2f97afb1cadaa0cfb782cb9d1b9ee2.zip
net: add real socket cookies
A long standing problem in netlink socket dumps is the use of kernel socket addresses as cookies. 1) It is a security concern. 2) Sockets can be reused quite quickly, so there is no guarantee a cookie is used once and identify a flow. 3) request sock, establish sock, and timewait socks for a given flow have different cookies. Part of our effort to bring better TCP statistics requires to switch to a different allocator. In this patch, I chose to use a per network namespace 64bit generator, and to use it only in the case a socket needs to be dumped to netlink. (This might be refined later if needed) Note that I tried to carry cookies from request sock, to establish sock, then timewait sockets. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Eric Salo <salo@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock_diag.c')
-rw-r--r--net/core/sock_diag.c37
1 files changed, 27 insertions, 10 deletions
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 96e70ee05a8d..74dddf84adcd 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -13,22 +13,39 @@ static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
static DEFINE_MUTEX(sock_diag_table_mutex);
-int sock_diag_check_cookie(void *sk, const __u32 *cookie)
+static u64 sock_gen_cookie(struct sock *sk)
{
- if ((cookie[0] != INET_DIAG_NOCOOKIE ||
- cookie[1] != INET_DIAG_NOCOOKIE) &&
- ((u32)(unsigned long)sk != cookie[0] ||
- (u32)((((unsigned long)sk) >> 31) >> 1) != cookie[1]))
- return -ESTALE;
- else
+ while (1) {
+ u64 res = atomic64_read(&sk->sk_cookie);
+
+ if (res)
+ return res;
+ res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
+ atomic64_cmpxchg(&sk->sk_cookie, 0, res);
+ }
+}
+
+int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
+{
+ u64 res;
+
+ if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
return 0;
+
+ res = sock_gen_cookie(sk);
+ if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
+ return -ESTALE;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
-void sock_diag_save_cookie(void *sk, __u32 *cookie)
+void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
{
- cookie[0] = (u32)(unsigned long)sk;
- cookie[1] = (u32)(((unsigned long)sk >> 31) >> 1);
+ u64 res = sock_gen_cookie(sk);
+
+ cookie[0] = (u32)res;
+ cookie[1] = (u32)(res >> 32);
}
EXPORT_SYMBOL_GPL(sock_diag_save_cookie);