From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: David Marchand <david.marchand@redhat.com>
Cc: Bruce Richardson <bruce.richardson@intel.com>,
"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: Thu, 1 Feb 2024 08:42:52 -0800 [thread overview]
Message-ID: <20240201164252.GA18071@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> (raw)
In-Reply-To: <CAJFAV8whb+_WZU+WmqSTSbUJJN6E_zgqEO64AUCixuPy9PUwWg@mail.gmail.com>
On Thu, Feb 01, 2024 at 12:45:43PM +0100, David Marchand wrote:
> On Tue, Aug 8, 2023 at 8:35 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > 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.
>
> Can we conclude?
> struct rte_tel_data seems internal (at least opaque from an
> application pov), so I suppose the option of changing data_len to
> size_t is still on the table.
>
> And we are missing a Fixes: tag too.
there is actually a general pattern of this problem across dpdk tree and
this fixes one instance.
i've marked the patch as rejected for now and hope to come back with a
more comprehensive series after msvc work is merged.
ty
>
> Thanks.
>
> --
> David Marchand
prev parent reply other threads:[~2024-02-01 16:42 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
2024-02-01 11:45 ` David Marchand
2024-02-01 16:42 ` Tyler Retzlaff [this message]
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