[net-next] rxrpc: Replace fake flex-array with flexible-array member

Commit Message

David Howells April 21, 2023, 1:08 p.m. UTC

From: Gustavo A. R. Silva <[e-mail]>

Zero-length arrays as fake flexible arrays are deprecated and we are
moving towards adopting C99 flexible-array members instead.

Transform zero-length array into flexible-array member in struct
rxrpc_ackpacket.

Address the following warnings found with GCC-13 and
-fstrict-flex-arrays=3 enabled:
net/rxrpc/call_event.c:149:38: warning: array subscript i is outside array bounds of ‘uint8_t[0]’ {aka ‘unsigned char[]’} [-Warray-bounds=]

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/21
Link: https://github.com/KSPP/linux/issues/263
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Signed-off-by: David Howells <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Jeffrey Altman <[e-mail]>
cc: Marc Dionne <[e-mail]>
cc: "David S. Miller" <[e-mail]>
cc: Eric Dumazet <[e-mail]>
cc: Jakub Kicinski <[e-mail]>
cc: Paolo Abeni <[e-mail]>
cc: [e-mail]
cc: [e-mail]
cc: [e-mail]
Link: https://lore.kernel.org/r/ZAZT11n4q5bBttW0@work/
---
 net/rxrpc/protocol.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

[e-mail] April 23, 2023, 12:50 p.m. UTC | #1

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <[e-mail]>:

On Fri, 21 Apr 2023 14:08:53 +0100 you wrote:
> From: Gustavo A. R. Silva <[e-mail]>
> 
> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
> 
> Transform zero-length array into flexible-array member in struct
> rxrpc_ackpacket.
> 
> [...]

Here is the summary with links:
  - [net-next] rxrpc: Replace fake flex-array with flexible-array member
    https://git.kernel.org/netdev/net-next/c/788352191c85

You are awesome, thank you!

Patch

diff --git a/net/rxrpc/protocol.h b/net/rxrpc/protocol.h
index 6760cb99c6d6..e8ee4af43ca8 100644
--- a/net/rxrpc/protocol.h
+++ b/net/rxrpc/protocol.h
@@ -126,7 +126,7 @@  struct rxrpc_ackpacket {
 	uint8_t		nAcks;		/* number of ACKs */
 #define RXRPC_MAXACKS	255
 
-	uint8_t		acks[0];	/* list of ACK/NAKs */
+	uint8_t		acks[];		/* list of ACK/NAKs */
 #define RXRPC_ACK_TYPE_NACK		0
 #define RXRPC_ACK_TYPE_ACK		1