[net] rxrpc: Fix memory leak in rxrpc_lookup_local

Commit Message

David Howells Jan. 28, 2021, 10:48 a.m. UTC

From: Takeshi Misawa <[e-mail]>

Commit 9ebeddef58c4 ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Then release ref in __rxrpc_put_peer and rxrpc_put_peer_locked.

	struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
	-               peer->local = local;
	+               peer->local = rxrpc_get_local(local);

rxrpc_discard_prealloc also need ref release in discarding.

syzbot report:
BUG: memory leak
unreferenced object 0xffff8881080ddc00 (size 256):
  comm "syz-executor339", pid 8462, jiffies 4294942238 (age 12.350s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 0a 00 00 00 00 c0 00 08 81 88 ff ff  ................
  backtrace:
    [<000000002b6e495f>] kmalloc include/linux/slab.h:552 [inline]
    [<000000002b6e495f>] kzalloc include/linux/slab.h:682 [inline]
    [<000000002b6e495f>] rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
    [<000000002b6e495f>] rxrpc_lookup_local+0x1c1/0x760 net/rxrpc/local_object.c:244
    [<000000006b43a77b>] rxrpc_bind+0x174/0x240 net/rxrpc/af_rxrpc.c:149
    [<00000000fd447a55>] afs_open_socket+0xdb/0x200 fs/afs/rxrpc.c:64
    [<000000007fd8867c>] afs_net_init+0x2b4/0x340 fs/afs/main.c:126
    [<0000000063d80ec1>] ops_init+0x4e/0x190 net/core/net_namespace.c:152
    [<00000000073c5efa>] setup_net+0xde/0x2d0 net/core/net_namespace.c:342
    [<00000000a6744d5b>] copy_net_ns+0x19f/0x3e0 net/core/net_namespace.c:483
    [<0000000017d3aec3>] create_new_namespaces+0x199/0x4f0 kernel/nsproxy.c:110
    [<00000000186271ef>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<000000002de7bac4>] ksys_unshare+0x2fe/0x5c0 kernel/fork.c:2957
    [<00000000349b12ba>] __do_sys_unshare kernel/fork.c:3025 [inline]
    [<00000000349b12ba>] __se_sys_unshare kernel/fork.c:3023 [inline]
    [<00000000349b12ba>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3023
    [<000000006d178ef7>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000637076d4>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 9ebeddef58c4 ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Signed-off-by: Takeshi Misawa <[e-mail]>
Reported-and-tested-by: [e-mail]
Signed-off-by: David Howells <[e-mail]>
---

 net/rxrpc/call_accept.c |    1 +
 1 file changed, 1 insertion(+)

Comments

[e-mail] Jan. 28, 2021, 9:20 p.m. UTC | #1

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Thu, 28 Jan 2021 10:48:36 +0000 you wrote:
> From: Takeshi Misawa <[e-mail]>
> 
> Commit 9ebeddef58c4 ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
> Then release ref in __rxrpc_put_peer and rxrpc_put_peer_locked.
> 
> 	struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
> 	-               peer->local = local;
> 	+               peer->local = rxrpc_get_local(local);
> 
> [...]

Here is the summary with links:
  - [net] rxrpc: Fix memory leak in rxrpc_lookup_local
    https://git.kernel.org/netdev/net/c/b8323f7288ab

You are awesome, thank you!
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Patch

diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 382add72c66f..1ae90fb97936 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -197,6 +197,7 @@  void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
 	tail = b->peer_backlog_tail;
 	while (CIRC_CNT(head, tail, size) > 0) {
 		struct rxrpc_peer *peer = b->peer_backlog[tail];
+		rxrpc_put_local(peer->local);
 		kfree(peer);
 		tail = (tail + 1) & (size - 1);
 	}