Messages in this thread | | | Date | Fri, 4 Mar 2022 21:24:47 -0800 | From | Jakub Kicinski <> | Subject | Re: [PATCH] net: atlantic: Avoid out-of-bounds indexing |
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On Fri, 4 Mar 2022 13:08:12 +0800 Kai-Heng Feng wrote: > UBSAN warnings are observed on atlantic driver: > [ 294.432996] UBSAN: array-index-out-of-bounds in /build/linux-Qow4fL/linux-5.15.0/drivers/net/ethernet/aquantia/atlantic/aq_nic.c:484:48 > [ 294.433695] index 8 is out of range for type 'aq_vec_s *[8]' > > The index is assigned right before breaking out the loop, so there's no actual > deferencing happening.
I think you're underselling it. This codes does not compute the address of the ring, it reads the ring pointer from an array. The description reads like it was doing:
ring = &self->ring[i];
which would indeed be valid. What the code actually does is not.
Please repost with the commit message improved and a Fixes: tag(s) pointing to commit(s) where the buggy code was introduced.
> So only use the index inside the loop to fix the issue. > > BugLink: https://bugs.launchpad.net/bugs/1958770 > Tested-by: Mario Limonciello <mario.limonciello@amd.com> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > .../net/ethernet/aquantia/atlantic/aq_vec.c | 24 +++++++++---------- > 1 file changed, 12 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c > index f4774cf051c97..6ab1f3212d246 100644 > --- a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c > +++ b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c > @@ -43,8 +43,8 @@ static int aq_vec_poll(struct napi_struct *napi, int budget) > if (!self) { > err = -EINVAL; > } else { > - for (i = 0U, ring = self->ring[0]; > - self->tx_rings > i; ++i, ring = self->ring[i]) { > + for (i = 0U; self->tx_rings > i; ++i) { > + ring = self->ring[i]; > u64_stats_update_begin(&ring[AQ_VEC_RX_ID].stats.rx.syncp); > ring[AQ_VEC_RX_ID].stats.rx.polls++; > u64_stats_update_end(&ring[AQ_VEC_RX_ID].stats.rx.syncp);
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