diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2018-05-03 17:04:59 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-05-04 01:16:11 +0200 |
| commit | 9ef09e35e521bf0df5325cc9cffa726a8f5f3c1b (patch) | |
| tree | eb370cdca5ac43b3ed7e9ce1e0e8ab14a54a673b /kernel | |
| parent | a8d7aa17bbc970971ccdf71988ea19230ab368b1 (diff) | |
bpf: fix possible spectre-v1 in find_and_alloc_map()
It's possible for userspace to control attr->map_type. Sanitize it when
using it as an array index to prevent an out-of-bounds value being used
under speculation.
Found by smatch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: netdev@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/syscall.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ebfe9f29dae8..8f434485abd2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -26,6 +26,7 @@ #include <linux/cred.h> #include <linux/timekeeping.h> #include <linux/ctype.h> +#include <linux/nospec.h> #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ @@ -102,12 +103,14 @@ const struct bpf_map_ops bpf_map_offload_ops = { static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) { const struct bpf_map_ops *ops; + u32 type = attr->map_type; struct bpf_map *map; int err; - if (attr->map_type >= ARRAY_SIZE(bpf_map_types)) + if (type >= ARRAY_SIZE(bpf_map_types)) return ERR_PTR(-EINVAL); - ops = bpf_map_types[attr->map_type]; + type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types)); + ops = bpf_map_types[type]; if (!ops) return ERR_PTR(-EINVAL); @@ -122,7 +125,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) if (IS_ERR(map)) return map; map->ops = ops; - map->map_type = attr->map_type; + map->map_type = type; return map; } |