From: Eric Dumazet <eric.dumazet@gmail.com>
To: Aditya Pakki <pakki001@umn.edu>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net/rds: Avoid potential use after free in rds_send_remove_from_sock
Date: Fri, 9 Apr 2021 12:26:15 +0200 [thread overview]
Message-ID: <bd3c84bc-6ae0-63e9-61f2-5cf64a976531@gmail.com> (raw)
In-Reply-To: <20210407000913.2207831-1-pakki001@umn.edu>
On 4/7/21 2:09 AM, Aditya Pakki wrote:
> In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource
> is freed and later under spinlock, causing potential use-after-free.
> Set the free pointer to NULL to avoid undefined behavior.
>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
> net/rds/message.c | 1 +
> net/rds/send.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/rds/message.c b/net/rds/message.c
> index 071a261fdaab..90ebcfe5fe3b 100644
> --- a/net/rds/message.c
> +++ b/net/rds/message.c
> @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm)
> rds_message_purge(rm);
>
> kfree(rm);
> + rm = NULL;
This is a nop really.
This does not clear @rm variable in the caller.
> }
> }
> EXPORT_SYMBOL_GPL(rds_message_put);
> diff --git a/net/rds/send.c b/net/rds/send.c
> index 985d0b7713ac..fe5264b9d4b3 100644
> --- a/net/rds/send.c
> +++ b/net/rds/send.c
> @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status)
> unlock_and_drop:
> spin_unlock_irqrestore(&rm->m_rs_lock, flags);
> rds_message_put(rm);
> - if (was_on_sock)
> + if (was_on_sock && rm)
> rds_message_put(rm);
Maybe the bug is that the refcount has not be elevated when was_on_sock
has been set.
> }
>
>
next prev parent reply other threads:[~2021-04-09 10:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 0:09 [PATCH] net/rds: Avoid potential use after free in rds_send_remove_from_sock Aditya Pakki
2021-04-07 18:26 ` Santosh Shilimkar
2021-04-07 21:10 ` patchwork-bot+netdevbpf
2021-04-09 10:26 ` Eric Dumazet [this message]
2021-04-19 22:12 ` Al Viro
2021-04-20 9:09 ` Leon Romanovsky
2021-04-20 9:11 ` Leon Romanovsky
2021-04-21 14:19 ` Krzysztof Kozlowski
2021-04-21 15:36 ` Leon Romanovsky
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