From: Petr Machata <petrm@nvidia.com>
To: Simon Horman <horms@kernel.org>
Cc: Gax-c <zichenxie0106@gmail.com>, <kuba@kernel.org>,
<andrew+netdev@lunn.ch>, <davem@davemloft.net>,
<edumazet@google.com>, <pabeni@redhat.com>, <petrm@nvidia.com>,
<idosch@nvidia.com>, <netdev@vger.kernel.org>,
<zzjas98@gmail.com>, <chenyuan0y@gmail.com>
Subject: Re: [PATCH v2] netdevsim: Add trailing zero to terminate the string in nsim_nexthop_bucket_activity_write()
Date: Thu, 24 Oct 2024 14:15:54 +0200 [thread overview]
Message-ID: <8734klit9w.fsf@nvidia.com> (raw)
In-Reply-To: <20241024105508.GA1202098@kernel.org>
Simon Horman <horms@kernel.org> writes:
> On Tue, Oct 22, 2024 at 12:19:08PM -0500, Gax-c wrote:
>
>> diff --git a/drivers/net/netdevsim/fib.c b/drivers/net/netdevsim/fib.c
>> index 41e80f78b316..16c382c42227 100644
>> --- a/drivers/net/netdevsim/fib.c
>> +++ b/drivers/net/netdevsim/fib.c
>> @@ -1377,10 +1377,12 @@ static ssize_t nsim_nexthop_bucket_activity_write(struct file *file,
>>
>> if (pos != 0)
>> return -EINVAL;
>> - if (size > sizeof(buf))
>> + if (size > sizeof(buf) - 1)
>
> I don't think this change for the best.
> If the input data is well formatted it will end with a '\0'.
> Which may be copied into the last byte of buf.
>
> With this change the maximum size of the input data is
> unnecessarily reduced by one.
The buffer is 128 bytes, and sscanf'd into it is a u32 and u16, say 18
bytes or so total. Arguably the buffer is unnecessarily large. I think
the -1 above doesn't hurt.
Though if (user_buf[size - 1]) return -EINVAL; would work, too?
next prev parent reply other threads:[~2024-10-24 12:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-22 17:19 [PATCH v2] netdevsim: Add trailing zero to terminate the string in nsim_nexthop_bucket_activity_write() Gax-c
2024-10-23 10:29 ` Petr Machata
2024-10-23 10:32 ` Petr Machata
2024-10-23 13:38 ` Ido Schimmel
2024-10-24 10:55 ` Simon Horman
2024-10-24 12:15 ` Petr Machata [this message]
2024-10-24 15:22 ` Simon Horman
2024-10-29 18:50 ` patchwork-bot+netdevbpf
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