netdev - Re: [PATCH net-next] bonding: Pass string literal as format argument of alloc_ordered

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Message-ID: <3239345.1722984212@famine>
Date: Tue, 06 Aug 2024 15:43:32 -0700
From: Jay Vosburgh <jv@...sburgh.net>
To: Simon Horman <horms@...nel.org>
cc: "David S. Miller" <davem@...emloft.net>,
    Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
    Paolo Abeni <pabeni@...hat.com>,
    Andy Gospodarek <andy@...yhouse.net>,
    Nathan Chancellor <nathan@...nel.org>,
    Nick Desaulniers <ndesaulniers@...gle.com>,
    Bill Wendling <morbo@...gle.com>,
    Justin Stitt <justinstitt@...gle.com>, netdev@...r.kernel.org,
    llvm@...ts.linux.dev
Subject: Re: [PATCH net-next] bonding: Pass string literal as format argument
 of alloc_ordered_workqueue()

Simon Horman <horms@...nel.org> wrote:

>Recently I noticed that both gcc-14 and clang-18 report that passing
>a non-string literal as the format argument of alloc_ordered_workqueue
>is potentially insecure.
>
>F.e. clang-18 says:
>
>.../bond_main.c:6384:37: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
> 6384 |         bond->wq = alloc_ordered_workqueue(bond_dev->name, WQ_MEM_RECLAIM);
>      |                                            ^~~~~~~~~~~~~~
>.../workqueue.h:524:18: note: expanded from macro 'alloc_ordered_workqueue'
>  524 |         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
>      |                         ^~~
>.../bond_main.c:6384:37: note: treat the string as an argument to avoid this
> 6384 |         bond->wq = alloc_ordered_workqueue(bond_dev->name, WQ_MEM_RECLAIM);
>      |                                            ^
>      |                                            "%s",
>..../workqueue.h:524:18: note: expanded from macro 'alloc_ordered_workqueue'
>  524 |         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
>      |                         ^
>
>Perhaps it is always the case where the contents of bond_dev->name is
>safe to pass as the format argument. That is, in my understanding, it
>never contains any format escape sequences.
>
>But, it seems better to be safe than sorry. And, as a bonus, compiler
>output becomes less verbose by addressing this issue as suggested by
>clang-18.
>
>Signed-off-by: Simon Horman <horms@...nel.org>

Acked-by: Jay Vosburgh <jv@...sburgh.net>

>---
> drivers/net/bonding/bond_main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 1cd92c12e782..f9633a6f8571 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -6338,7 +6338,8 @@ static int bond_init(struct net_device *bond_dev)
> 
> 	netdev_dbg(bond_dev, "Begin bond_init\n");
> 
>-	bond->wq = alloc_ordered_workqueue(bond_dev->name, WQ_MEM_RECLAIM);
>+	bond->wq = alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM,
>+					   bond_dev->name);
> 	if (!bond->wq)
> 		return -ENOMEM;
> 
>