In [0], we added the ability to bpf_prog_attach LSM programs to cgroups, but in our validation to make sure the prog is meant to be attached to BPF_LSM_CGROUP, we return too early if the check fails. This results in lack of decrementing prog's refcnt (through bpf_prog_put) leaving the LSM program alive past the point of the expected lifecycle. This fix allows for the decrement to take place. [0] https://lore.kernel.org/all/20220628174314.1216643-4-sdf@xxxxxxxxxx/ Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor") Signed-off-by: Milan Landaverde <milan@xxxxxxxxxxxx> --- kernel/bpf/syscall.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 35972afb6850..64131f88c553 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3518,9 +3518,9 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_PROG_TYPE_LSM: if (ptype == BPF_PROG_TYPE_LSM && prog->expected_attach_type != BPF_LSM_CGROUP) - return -EINVAL; - - ret = cgroup_bpf_prog_attach(attr, ptype, prog); + ret = -EINVAL; + else + ret = cgroup_bpf_prog_attach(attr, ptype, prog); break; default: ret = -EINVAL; -- 2.34.1
