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| author | Alexei Starovoitov <ast@kernel.org> | 2021-03-07 14:52:48 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-03-08 13:32:46 +0100 |
| commit | 350a5c4dd2452ea999cc5e1d4a8dbf12de2f97ef (patch) | |
| tree | 5270bd1ec9edc2878100f37ab9eeaaf2c169947f /kernel/bpf/syscall.c | |
| parent | edbea922025169c0e5cdca5ebf7bf5374cc5566c (diff) | |
| download | linux-350a5c4dd2452ea999cc5e1d4a8dbf12de2f97ef.tar.bz2 | |
bpf: Dont allow vmlinux BTF to be used in map_create and prog_load.
The syzbot got FD of vmlinux BTF and passed it into map_create which caused
crash in btf_type_id_size() when it tried to access resolved_ids. The vmlinux
BTF doesn't have 'resolved_ids' and 'resolved_sizes' initialized to save
memory. To avoid such issues disallow using vmlinux BTF in prog_load and
map_create commands.
Fixes: 5329722057d4 ("bpf: Assign ID to vmlinux BTF and return extra info for BTF in GET_OBJ_INFO")
Reported-by: syzbot+8bab8ed346746e7540e8@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210307225248.79031-1-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c859bc46d06c..250503482cda 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -854,6 +854,11 @@ static int map_create(union bpf_attr *attr) err = PTR_ERR(btf); goto free_map; } + if (btf_is_kernel(btf)) { + btf_put(btf); + err = -EACCES; + goto free_map; + } map->btf = btf; if (attr->btf_value_type_id) { |