diff options
| author | Martynas Pumputis <m@lambda.lt> | 2021-07-05 14:43:07 +0200 |
|---|---|---|
| committer | Stephen Hemminger <stephen@networkplumber.org> | 2021-07-06 16:59:39 -0700 |
| commit | 83d4d61bc90e38eaf483f8c6f94f3f7059f07bc9 (patch) | |
| tree | c98c201c8e23bab4bd1a82b5460337fbd82f5e78 | |
| parent | 02c06ffc13b40da269584eff42eb850b4d54c921 (diff) | |
| download | iproute2-83d4d61bc90e38eaf483f8c6f94f3f7059f07bc9.tar.gz | |
libbpf: fix attach of prog with multiple sections
When BPF programs which consists of multiple executable sections via
iproute2+libbpf (configured with LIBBPF_FORCE=on), we noticed that a
wrong section can be attached to a device. E.g.:
# tc qdisc replace dev lxc_health clsact
# tc filter replace dev lxc_health ingress prio 1 \
handle 1 bpf da obj bpf_lxc.o sec from-container
# tc filter show dev lxc_health ingress filter protocol all
pref 1 bpf chain 0 filter protocol all pref 1 bpf chain 0
handle 0x1 bpf_lxc.o:[__send_drop_notify] <-- WRONG SECTION
direct-action not_in_hw id 38 tag 7d891814eda6809e jited
After taking a closer look into load_bpf_object() in lib/bpf_libbpf.c,
we noticed that the filter used in the program iterator does not check
whether a program section name matches a requested section name
(cfg->section). This can lead to a wrong prog FD being used to attach
the program.
Fixes: 6d61a2b55799 ("lib: add libbpf support")
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Hangbin Liu <haliu@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
| -rw-r--r-- | lib/bpf_libbpf.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c index 864f8c35..dbec2cb5 100644 --- a/lib/bpf_libbpf.c +++ b/lib/bpf_libbpf.c @@ -268,10 +268,12 @@ static int load_bpf_object(struct bpf_cfg_in *cfg) } bpf_object__for_each_program(p, obj) { + bool prog_to_attach = !prog && cfg->section && + !strcmp(get_bpf_program__section_name(p), cfg->section); + /* Only load the programs that will either be subsequently * attached or inserted into a tail call map */ - if (find_legacy_tail_calls(p, obj) < 0 && cfg->section && - strcmp(get_bpf_program__section_name(p), cfg->section)) { + if (find_legacy_tail_calls(p, obj) < 0 && !prog_to_attach) { ret = bpf_program__set_autoload(p, false); if (ret) return -EINVAL; @@ -280,7 +282,8 @@ static int load_bpf_object(struct bpf_cfg_in *cfg) bpf_program__set_type(p, cfg->type); bpf_program__set_ifindex(p, cfg->ifindex); - if (!prog) + + if (prog_to_attach) prog = p; } |