diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-02-22 13:50:13 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-09-04 14:17:36 +0300 |
| commit | 95e49b925812cbc6a72254f61cf7090e93d3ecd8 (patch) | |
| tree | 4ca8ef631f9d5b61f1ada7394fe93d70740072f0 | |
| parent | 316bf51edd3ef0754e3350ef4ea006d1bbf57d7e (diff) | |
| download | linux-95e49b925812cbc6a72254f61cf7090e93d3ecd8.tar.xz | |
netlink: hold nlk->cb_mutex longer in __netlink_dump_start()
[ Upstream commit b5590270068c4324dac4a2b5a4a156e02e21339f ]
__netlink_dump_start() releases nlk->cb_mutex right before
calling netlink_dump() which grabs it again.
This seems dangerous, even if KASAN did not bother yet.
Add a @lock_taken parameter to netlink_dump() to let it
grab the mutex if called from netlink_recvmsg() only.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/netlink/af_netlink.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index ac3678d2d6d5..4f2a3d46554f 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -126,7 +126,7 @@ static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { "nlk_cb_mutex-MAX_LINKS" }; -static int netlink_dump(struct sock *sk); +static int netlink_dump(struct sock *sk, bool lock_taken); /* nl_table locking explained: * Lookup and traversal are protected with an RCU read-side lock. Insertion @@ -1996,7 +1996,7 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, if (READ_ONCE(nlk->cb_running) && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { - ret = netlink_dump(sk); + ret = netlink_dump(sk, false); if (ret) { sk->sk_err = -ret; sk->sk_error_report(sk); @@ -2206,7 +2206,7 @@ static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, return 0; } -static int netlink_dump(struct sock *sk) +static int netlink_dump(struct sock *sk, bool lock_taken) { struct netlink_sock *nlk = nlk_sk(sk); struct netlink_ext_ack extack = {}; @@ -2218,7 +2218,8 @@ static int netlink_dump(struct sock *sk) int alloc_min_size; int alloc_size; - mutex_lock(nlk->cb_mutex); + if (!lock_taken) + mutex_lock(nlk->cb_mutex); if (!nlk->cb_running) { err = -EINVAL; goto errout_skb; @@ -2374,9 +2375,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, WRITE_ONCE(nlk->cb_running, true); nlk->dump_done_errno = INT_MAX; - mutex_unlock(nlk->cb_mutex); - - ret = netlink_dump(sk); + ret = netlink_dump(sk, true); sock_put(sk); |