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Message-ID: <20240307120340.99577-1-toke@redhat.com>
Date: Thu, 7 Mar 2024 13:03:34 +0100
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Jesper Dangaard Brouer <hawk@...nel.org>,
John Fastabend <john.fastabend@...il.com>,
Andrii Nakryiko <andrii@...nel.org>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>,
Toke Høiland-Jørgensen <toke@...hat.com>,
Bui Quang Minh <minhquangbui99@...il.com>
Cc: Jesper Dangaard Brouer <brouer@...hat.com>,
netdev@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH bpf v3 0/3] Fix hash bucket overflow checks for 32-bit arches
Syzbot managed to trigger a crash by creating a DEVMAP_HASH map with a
large number of buckets because the overflow check relies on
well-defined behaviour that is only correct on 64-bit arches.
Fix the overflow checks to happen before values are rounded up in all
the affected map types.
v3:
- Keep the htab->n_buckets > U32_MAX / sizeof(struct bucket) check
- Use 1UL << 31 instead of U32_MAX / 2 + 1 as the constant to check
against
- Add patch to fix stackmap.c
v2:
- Fix off-by-one error in overflow check
- Apply the same fix to hashtab, where the devmap_hash code was copied
from (John)
Toke Høiland-Jørgensen (3):
bpf: Fix DEVMAP_HASH overflow check on 32-bit arches
bpf: Fix hashtab overflow check on 32-bit arches
bpf: Fix stackmap overflow check on 32-bit arches
kernel/bpf/devmap.c | 11 ++++++-----
kernel/bpf/hashtab.c | 14 +++++++++-----
kernel/bpf/stackmap.c | 9 ++++++---
3 files changed, 21 insertions(+), 13 deletions(-)
--
2.43.2
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