diff options
| author | Yuntao Wang <ytcoode@gmail.com> | 2022-04-30 21:08:03 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-06 08:42:45 +0200 |
| commit | 7f845de2863334bed4f362e95853f5e7bc323737 (patch) | |
| tree | 866a50d0a9ead3538598029f5d50a4a47917ac8a | |
| parent | 3097f38e91266c7132c3fdb7e778fac858c00670 (diff) | |
bpf: Fix potential array overflow in bpf_trampoline_get_progs()
commit a2aa95b71c9bbec793b5c5fa50f0a80d882b3e8d upstream.
The cnt value in the 'cnt >= BPF_MAX_TRAMP_PROGS' check does not
include BPF_TRAMP_MODIFY_RETURN bpf programs, so the number of
the attached BPF_TRAMP_MODIFY_RETURN bpf programs in a trampoline
can exceed BPF_MAX_TRAMP_PROGS.
When this happens, the assignment '*progs++ = aux->prog' in
bpf_trampoline_get_progs() will cause progs array overflow as the
progs field in the bpf_tramp_progs struct can only hold at most
BPF_MAX_TRAMP_PROGS bpf programs.
Fixes: 88fd9e5352fe ("bpf: Refactor trampoline update code")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Link: https://lore.kernel.org/r/20220430130803.210624-1-ytcoode@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/bpf/trampoline.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 986dabc3d11f..87becf77cc75 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -378,7 +378,7 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) { enum bpf_tramp_prog_type kind; int err = 0; - int cnt; + int cnt = 0, i; kind = bpf_attach_type_to_tramp(prog); mutex_lock(&tr->mutex); @@ -389,7 +389,10 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr) err = -EBUSY; goto out; } - cnt = tr->progs_cnt[BPF_TRAMP_FENTRY] + tr->progs_cnt[BPF_TRAMP_FEXIT]; + + for (i = 0; i < BPF_TRAMP_MAX; i++) + cnt += tr->progs_cnt[i]; + if (kind == BPF_TRAMP_REPLACE) { /* Cannot attach extension if fentry/fexit are in use. */ if (cnt) { @@ -467,16 +470,19 @@ out: void bpf_trampoline_put(struct bpf_trampoline *tr) { + int i; + if (!tr) return; mutex_lock(&trampoline_mutex); if (!refcount_dec_and_test(&tr->refcnt)) goto out; WARN_ON_ONCE(mutex_is_locked(&tr->mutex)); - if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FENTRY]))) - goto out; - if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FEXIT]))) - goto out; + + for (i = 0; i < BPF_TRAMP_MAX; i++) + if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[i]))) + goto out; + /* This code will be executed even when the last bpf_tramp_image * is alive. All progs are detached from the trampoline and the * trampoline image is patched with jmp into epilogue to skip |