From: Bruce Richardson <bruce.richardson@intel.com>
To: Tyler Retzlaff <roretzla@linux.microsoft.com>
Cc: "lihuisong (C)" <lihuisong@huawei.com>, <dev@dpdk.org>,
Ciara Power <ciara.power@intel.com>
Subject: Re: [PATCH] telemetry: avoid truncation of strlcpy return before check
Date: Tue, 8 Aug 2023 19:35:28 +0100 [thread overview]
Message-ID: <ZNKK8GKvW+CTE3Mx@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <20230808175937.GA13736@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
On Tue, Aug 08, 2023 at 10:59:37AM -0700, Tyler Retzlaff wrote:
> On Tue, Aug 08, 2023 at 10:24:41AM +0800, lihuisong (C) wrote:
> >
> > 在 2023/8/3 5:21, Tyler Retzlaff 写道:
> > >strlcpy returns type size_t when directly assigning to
> > >struct rte_tel_data data_len field it may be truncated leading to
> > >compromised length check that follows
> > >
> > >Since the limit in the check is < UINT_MAX the value returned is
> > >safe to be cast to unsigned int (which may be narrower than size_t)
> > >but only after being checked against RTE_TEL_MAX_SINGLE_STRING_LEN
> > >
> > >Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> > >---
> > > lib/telemetry/telemetry_data.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > >diff --git a/lib/telemetry/telemetry_data.c b/lib/telemetry/telemetry_data.c
> > >index 3b1a240..52307cb 100644
> > >--- a/lib/telemetry/telemetry_data.c
> > >+++ b/lib/telemetry/telemetry_data.c
> > >@@ -41,12 +41,13 @@
> > > int
> > > rte_tel_data_string(struct rte_tel_data *d, const char *str)
> > > {
> > >+ const size_t len = strlcpy(d->data.str, str, sizeof(d->data.str));
> > sizeof(d->data.str) is equal to RTE_TEL_MAX_SINGLE_STRING_LEN(8192).
> > So It seems that this truncation probably will not happen.
>
> agreed, regardless the data type choices permit a size that exceeds the
> range of the narrower type and the assignment results in a warning being
> generated on some targets. that's why the truncating cast is safe to
> add.
>
> none of this would be necessary if data_len had been appropriately typed
> as size_t. Bruce should we be changing the type instead since we are in
> 23.11 merge window...?
>
I'm fine either way, to be honest.
next prev parent reply other threads:[~2023-08-08 18:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-02 21:21 Tyler Retzlaff
2023-08-03 8:15 ` Bruce Richardson
2023-08-08 2:24 ` lihuisong (C)
2023-08-08 17:59 ` Tyler Retzlaff
2023-08-08 18:35 ` Bruce Richardson [this message]
2024-02-01 11:45 ` David Marchand
2024-02-01 16:42 ` Tyler Retzlaff
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