From 9ef09e35e521bf0df5325cc9cffa726a8f5f3c1b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 3 May 2018 17:04:59 +0100 Subject: 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 Cc: Alexei Starovoitov Cc: Dan Carpenter Cc: Daniel Borkmann Cc: Peter Zijlstra Cc: netdev@vger.kernel.org Acked-by: David S. Miller Signed-off-by: Daniel Borkmann --- kernel/bpf/syscall.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') 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 #include #include +#include #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; } -- cgit v1.2.1 From d0f1a451e33d9ca834422622da30aa68daade56b Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 4 May 2018 02:13:57 +0200 Subject: bpf: use array_index_nospec in find_prog_type Commit 9ef09e35e521 ("bpf: fix possible spectre-v1 in find_and_alloc_map()") converted find_and_alloc_map() over to use array_index_nospec() to sanitize map type that user space passes on map creation, and this patch does an analogous conversion for progs in find_prog_type() as it's also passed from user space when loading progs as attr->prog_type. Signed-off-by: Daniel Borkmann Cc: Mark Rutland Signed-off-by: Alexei Starovoitov --- kernel/bpf/syscall.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8f434485abd2..016ef9025827 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -874,11 +874,17 @@ static const struct bpf_prog_ops * const bpf_prog_types[] = { static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) { - if (type >= ARRAY_SIZE(bpf_prog_types) || !bpf_prog_types[type]) + const struct bpf_prog_ops *ops; + + if (type >= ARRAY_SIZE(bpf_prog_types)) + return -EINVAL; + type = array_index_nospec(type, ARRAY_SIZE(bpf_prog_types)); + ops = bpf_prog_types[type]; + if (!ops) return -EINVAL; if (!bpf_prog_is_dev_bound(prog->aux)) - prog->aux->ops = bpf_prog_types[type]; + prog->aux->ops = ops; else prog->aux->ops = &bpf_offload_prog_ops; prog->type = type; -- cgit v1.2.1