The patch below does not apply to the 6.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

1c123c567fb1 ("bpf: Resolve fext program type when checking map compatibility")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1c123c567fb138ebd187480b7fc0610fcb0851f5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= toke@redhat.com Date: Thu, 15 Dec 2022 00:02:53 +0100 Subject: [PATCH] bpf: Resolve fext program type when checking map compatibility MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

The bpf_prog_map_compatible() check makes sure that BPF program types are not mixed inside BPF map types that can contain programs (tail call maps, cpumaps and devmaps). It does this by setting the fields of the map->owner struct to the values of the first program being checked against, and rejecting any subsequent programs if the values don't match.

One of the values being set in the map owner struct is the program type, and since the code did not resolve the prog type for fext programs, the map owner type would be set to PROG_TYPE_EXT and subsequent loading of programs of the target type into the map would fail.

This bug is seen in particular for XDP programs that are loaded as PROG_TYPE_EXT using libxdp; these cannot insert programs into devmaps and cpumaps because the check fails as described above.

Fix the bug by resolving the fext program type to its target program type as elsewhere in the verifier.

v3: - Add Yonghong's ACK

Fixes: f45d5b6ce2e8 ("bpf: generalise tail call map compatibility check") Acked-by: Yonghong Song yhs@fb.com Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com Link: https://lore.kernel.org/r/20221214230254.790066-1-toke@redhat.com Signed-off-by: Martin KaFai Lau martin.lau@kernel.org

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 7f98dec6e90f..b334f4ddc4d5 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2092,6 +2092,7 @@ static unsigned int __bpf_prog_ret0_warn(const void *ctx, bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp) { + enum bpf_prog_type prog_type = resolve_prog_type(fp); bool ret;

if (fp->kprobe_override) @@ -2102,12 +2103,12 @@ bool bpf_prog_map_compatible(struct bpf_map *map, /* There's no owner yet where we could check for * compatibility. */ - map->owner.type = fp->type; + map->owner.type = prog_type; map->owner.jited = fp->jited; map->owner.xdp_has_frags = fp->aux->xdp_has_frags; ret = true; } else { - ret = map->owner.type == fp->type && + ret = map->owner.type == prog_type && map->owner.jited == fp->jited && map->owner.xdp_has_frags == fp->aux->xdp_has_frags; }