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Message-ID: <f0cef998-0d49-4a52-b1b8-2f89b81d4b07@linux.dev>
Date: Fri, 3 Oct 2025 21:28:51 -0700
From: Zhu Yanjun <yanjun.zhu@...ux.dev>
To: Pavel Zhigulin <Pavel.Zhigulin@...persky.com>,
Ayush Sawal <ayush.sawal@...lsio.com>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Leon Romanovsky <leon@...nel.org>,
Steffen Klassert <steffen.klassert@...unet.com>,
Cosmin Ratiu <cratiu@...dia.com>, Harsh Jain <harsh@...lsio.com>,
Atul Gupta <atul.gupta@...lsio.com>, Herbert Xu
<herbert@...dor.apana.org.au>, Ganesh Goudar <ganeshgr@...lsio.com>,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
lvc-project@...uxtesting.org
Subject: Re: [PATCH] net: fix potential use-after-free in
ch_ipsec_xfrm_add_state() callback
在 2025/10/1 4:16, Pavel Zhigulin 写道:
> In ch_ipsec_xfrm_add_state() there is not check of try_module_get
> return value. It is very unlikely, but try_module_get() could return
> false value, which could cause use-after-free error.
>
> This fix adds checking the result of try_module_get call
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 6dad4e8ab3ec ("chcr: Add support for Inline IPSec")
> Signed-off-by: Pavel Zhigulin <Pavel.Zhigulin@...persky.com>
> ---
> .../net/ethernet/chelsio/inline_crypto/ch_ipsec/chcr_ipsec.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/chelsio/inline_crypto/ch_ipsec/chcr_ipsec.c b/drivers/net/ethernet/chelsio/inline_crypto/ch_ipsec/chcr_ipsec.c
> index ecd9a0bd5e18..3a5277630afa 100644
> --- a/drivers/net/ethernet/chelsio/inline_crypto/ch_ipsec/chcr_ipsec.c
> +++ b/drivers/net/ethernet/chelsio/inline_crypto/ch_ipsec/chcr_ipsec.c
> @@ -35,6 +35,8 @@
> * Atul Gupta (atul.gupta@...lsio.com)
> */
>
> +#include "asm-generic/errno-base.h"
> +#include "linux/compiler.h"
> #define pr_fmt(fmt) "ch_ipsec: " fmt
>
> #include <linux/kernel.h>
> @@ -301,7 +303,8 @@ static int ch_ipsec_xfrm_add_state(struct net_device *dev,
> sa_entry->esn = 1;
> ch_ipsec_setkey(x, sa_entry);
> x->xso.offload_handle = (unsigned long)sa_entry;
> - try_module_get(THIS_MODULE);
> + if (unlikely(!try_module_get(THIS_MODULE)))
The function try_module_get() fails (returns false) only if the module
is in the process of being
unloaded (i.e., module_refcount can’t be increased because the state is
GOING
or UNFORMED). Otherwise, it succeeds and increments the refcount.
When the function ch_ipsec_xfrm_add_state is called, the kernel module
cannot be in the GOING
or UNFORMED state. In other words, within this function, it is not
possible for try_module_get to fail.
I am not sure if this check is strictly necessary, but as a defensive
programming measure, it still makes sense.
Reviewed-by: Zhu Yanjun <yanjun.zhu@...ux.dev>
Zhu Yanjun
> + res = -ENODEV;
> out:
> return res;
> }
> --
> 2.43.0
>
--
Best Regards,
Yanjun.Zhu
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