[PATCH net-next] rxrpc: Fix uninitialized error code in rxrpc_send_data_packet()

[PATCH net-next] rxrpc: Fix uninitialized error code in rxrpc_send_data_packet()

[David Howells]

With gcc 4.1:

    net/rxrpc/output.c: In function ‘rxrpc_send_data_packet’:
    net/rxrpc/output.c:338: warning: ‘ret’ may be used uninitialized in this function

Indeed, if the first jump to the send_fragmentable label is made, and
the address family is not handled in the switch() statement, ret will be
used uninitialized.

Fix this by BUG()'ing as is done in other places in rxrpc where internal
support for future address families will need adding.  It should not be
possible to reach this normally as the address families are checked
up-front.

Fixes: 5a924b8951f835b5 ("rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Howells <dhowells@redhat.com>
---

 net/rxrpc/output.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index a0b6abfbd277..948e3fe249ec 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -519,6 +519,9 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 		}
 		break;
 #endif
+
+	default:
+		BUG();
 	}
 
 	if (ret < 0)

Re: [PATCH net-next] rxrpc: Fix uninitialized error code in rxrpc_send_data_packet()

[David Miller]

From: David Howells <dhowells@redhat.com>
Date: Tue, 02 Jul 2019 15:55:28 +0100

> With gcc 4.1:
> 
>     net/rxrpc/output.c: In function ‘rxrpc_send_data_packet’:
>     net/rxrpc/output.c:338: warning: ‘ret’ may be used uninitialized in this function
> 
> Indeed, if the first jump to the send_fragmentable label is made, and
> the address family is not handled in the switch() statement, ret will be
> used uninitialized.
> 
> Fix this by BUG()'ing as is done in other places in rxrpc where internal
> support for future address families will need adding.  It should not be
> possible to reach this normally as the address families are checked
> up-front.
> 
> Fixes: 5a924b8951f835b5 ("rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs")
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: David Howells <dhowells@redhat.com>

Applied, thanks David.