[PATCH 6.6.y] bpf: Add missing BPF_LINK_TYPE invocations

[PATCH 6.6.y] bpf: Add missing BPF_LINK_TYPE invocations

[Ignat Korchagin]

From: Jiri Olsa <jolsa@kernel.org>

commit 117211aa739a926e6555cfea883be84bee6f1695 upstream.

Pengfei Xu reported [1] Syzkaller/KASAN issue found in bpf_link_show_fdinfo.

The reason is missing BPF_LINK_TYPE invocation for uprobe multi
link and for several other links, adding that.

[1] https://lore.kernel.org/bpf/ZXptoKRSLspnk2ie@xpf.sh.intel.com/

Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
Fixes: 84601d6ee68a ("bpf: add bpf_link support for BPF_NETFILTER programs")
Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/bpf/20231215230502.2769743-1-jolsa@kernel.org
Cc: stable@vger.kernel.org # 6.6
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
---
Hi,

We have experienced a KASAN warning in production on a 6.6 kernel, similar to
[1]. This backported patch was adjusted to apply onto 6.6 stable branch: the
only change is dropping the BPF_LINK_TYPE(BPF_LINK_TYPE_NETKIT, netkit)
definition from the header as netkit was only introduced in 6.7 and 6.7 has the
backport already.

I was not able to run the syzkaller reproducer from [1], but we have not seen
the KASAN warning in production since applying this patch internally.

Regards,
Ignat 

 include/linux/bpf_types.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index fc0d6f32c687..dfaae3e3ec15 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -142,9 +142,12 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter)
 #ifdef CONFIG_NET
 BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns)
 BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp)
+BPF_LINK_TYPE(BPF_LINK_TYPE_NETFILTER, netfilter)
+BPF_LINK_TYPE(BPF_LINK_TYPE_TCX, tcx)
 #endif
 #ifdef CONFIG_PERF_EVENTS
 BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf)
 #endif
 BPF_LINK_TYPE(BPF_LINK_TYPE_KPROBE_MULTI, kprobe_multi)
 BPF_LINK_TYPE(BPF_LINK_TYPE_STRUCT_OPS, struct_ops)
+BPF_LINK_TYPE(BPF_LINK_TYPE_UPROBE_MULTI, uprobe_multi)
-- 
2.39.2

Re: [PATCH 6.6.y] bpf: Add missing BPF_LINK_TYPE invocations

[Greg KH]

On Tue, May 21, 2024 at 11:18:26AM +0100, Ignat Korchagin wrote:
> From: Jiri Olsa <jolsa@kernel.org>
> 
> commit 117211aa739a926e6555cfea883be84bee6f1695 upstream.
> 
> Pengfei Xu reported [1] Syzkaller/KASAN issue found in bpf_link_show_fdinfo.
> 
> The reason is missing BPF_LINK_TYPE invocation for uprobe multi
> link and for several other links, adding that.
> 
> [1] https://lore.kernel.org/bpf/ZXptoKRSLspnk2ie@xpf.sh.intel.com/
> 
> Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
> Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
> Fixes: 84601d6ee68a ("bpf: add bpf_link support for BPF_NETFILTER programs")
> Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
> Reported-by: Pengfei Xu <pengfei.xu@intel.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> Tested-by: Pengfei Xu <pengfei.xu@intel.com>
> Acked-by: Hou Tao <houtao1@huawei.com>
> Link: https://lore.kernel.org/bpf/20231215230502.2769743-1-jolsa@kernel.org
> Cc: stable@vger.kernel.org # 6.6
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
> ---
> Hi,
> 
> We have experienced a KASAN warning in production on a 6.6 kernel, similar to
> [1]. This backported patch was adjusted to apply onto 6.6 stable branch: the
> only change is dropping the BPF_LINK_TYPE(BPF_LINK_TYPE_NETKIT, netkit)
> definition from the header as netkit was only introduced in 6.7 and 6.7 has the
> backport already.
> 
> I was not able to run the syzkaller reproducer from [1], but we have not seen
> the KASAN warning in production since applying this patch internally.

Looks good, thanks for the backport, now queued up.

greg k-h