[PATCH v2][next] tls: Avoid -Wflex-array-member-not-at-end warning

[PATCH v2][next] tls: Avoid -Wflex-array-member-not-at-end warning

[Gustavo A. R. Silva]

Remove unused flexible-array member in struct tls_rec and, with this,
fix the following warning:

net/tls/tls.h:131:29: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Also, add a comment to prevent people from adding any members
after struct aead_request, which is a flexible structure --this is
a structure that ends in a flexible-array member.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
 - Remove unused flex array. (Sabrina Dubroca).
 - Update changelog text.

v1:
 - Link: https://lore.kernel.org/linux-hardening/aNFfmBLEoDSBSLJe@kspp/

 net/tls/tls.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/tls/tls.h b/net/tls/tls.h
index 4e077068e6d9..06d462c57284 100644
--- a/net/tls/tls.h
+++ b/net/tls/tls.h
@@ -128,8 +128,9 @@ struct tls_rec {
 
 	char aad_space[TLS_AAD_SPACE_SIZE];
 	u8 iv_data[TLS_MAX_IV_SIZE];
+
+	/* Must be last --ends in a flexible-array member. */
 	struct aead_request aead_req;
-	u8 aead_req_ctx[];
 };
 
 int __net_init tls_proc_init(struct net *net);
-- 
2.43.0

Re: [PATCH v2][next] tls: Avoid -Wflex-array-member-not-at-end warning

[Sabrina Dubroca]

Thanks for the updated patch.

A process nit: the correct subject prefix for this type of work within
networking would be [PATCH net-next v2] (indicating it targets the
"net-next" tree).

2025-09-23, 22:45:10 +0200, Gustavo A. R. Silva wrote:
> Remove unused flexible-array member in struct tls_rec and, with this,
> fix the following warning:
> 
> net/tls/tls.h:131:29: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Also, add a comment to prevent people from adding any members
> after struct aead_request, which is a flexible structure --this is
> a structure that ends in a flexible-array member.

Once that warning is enabled, re-adding a field after aead_req will
not be allowed by the compiler, right?  The comment is probably not
really needed, but since there are "must be first" comments all over
include/net, I guess it's useful.

Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>

-- 
Sabrina

Re: [PATCH v2][next] tls: Avoid -Wflex-array-member-not-at-end warning

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 23 Sep 2025 22:45:10 +0200 you wrote:
> Remove unused flexible-array member in struct tls_rec and, with this,
> fix the following warning:
> 
> net/tls/tls.h:131:29: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Also, add a comment to prevent people from adding any members
> after struct aead_request, which is a flexible structure --this is
> a structure that ends in a flexible-array member.
> 
> [...]

Here is the summary with links:
  - [v2,next] tls: Avoid -Wflex-array-member-not-at-end warning
    https://git.kernel.org/netdev/net-next/c/b6db19d1df8a

You are awesome, thank you!
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