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bpf: Extract nullable reg type conversion into a helper function

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Extract conversion from a register's nullable type to a type with a
value. The helper will be used in mark_ptr_not_null_reg().

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212205642.620788-3-me@ubique.spb.ru
This commit is contained in:
Dmitrii Banshchikov 2021-02-13 00:56:40 +04:00 committed by Alexei Starovoitov
parent feb4adfad5
commit 4ddb74165a
1 changed files with 52 additions and 31 deletions
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83
kernel/bpf/verifier.c
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@ -1079,6 +1079,51 @@ static void mark_reg_known_zero(struct bpf_verifier_env *env,
__mark_reg_known_zero(regs + regno);
}
static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
{
switch (reg->type) {
case PTR_TO_MAP_VALUE_OR_NULL: {
const struct bpf_map *map = reg->map_ptr;
if (map->inner_map_meta) {
reg->type = CONST_PTR_TO_MAP;
reg->map_ptr = map->inner_map_meta;
} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
reg->type = PTR_TO_XDP_SOCK;
} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
map->map_type == BPF_MAP_TYPE_SOCKHASH) {
reg->type = PTR_TO_SOCKET;
} else {
reg->type = PTR_TO_MAP_VALUE;
}
break;
}
case PTR_TO_SOCKET_OR_NULL:
reg->type = PTR_TO_SOCKET;
break;
case PTR_TO_SOCK_COMMON_OR_NULL:
reg->type = PTR_TO_SOCK_COMMON;
break;
case PTR_TO_TCP_SOCK_OR_NULL:
reg->type = PTR_TO_TCP_SOCK;
break;
case PTR_TO_BTF_ID_OR_NULL:
reg->type = PTR_TO_BTF_ID;
break;
case PTR_TO_MEM_OR_NULL:
reg->type = PTR_TO_MEM;
break;
case PTR_TO_RDONLY_BUF_OR_NULL:
reg->type = PTR_TO_RDONLY_BUF;
break;
case PTR_TO_RDWR_BUF_OR_NULL:
reg->type = PTR_TO_RDWR_BUF;
break;
default:
WARN_ON("unknown nullable register type");
}
}
static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
{
return type_is_pkt_pointer(reg->type);
@ -7737,43 +7782,19 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
}
if (is_null) {
reg->type = SCALAR_VALUE;
} else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
const struct bpf_map *map = reg->map_ptr;
if (map->inner_map_meta) {
reg->type = CONST_PTR_TO_MAP;
reg->map_ptr = map->inner_map_meta;
} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
reg->type = PTR_TO_XDP_SOCK;
} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
map->map_type == BPF_MAP_TYPE_SOCKHASH) {
reg->type = PTR_TO_SOCKET;
} else {
reg->type = PTR_TO_MAP_VALUE;
}
} else if (reg->type == PTR_TO_SOCKET_OR_NULL) {
reg->type = PTR_TO_SOCKET;
} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
reg->type = PTR_TO_SOCK_COMMON;
} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
reg->type = PTR_TO_TCP_SOCK;
} else if (reg->type == PTR_TO_BTF_ID_OR_NULL) {
reg->type = PTR_TO_BTF_ID;
} else if (reg->type == PTR_TO_MEM_OR_NULL) {
reg->type = PTR_TO_MEM;
} else if (reg->type == PTR_TO_RDONLY_BUF_OR_NULL) {
reg->type = PTR_TO_RDONLY_BUF;
} else if (reg->type == PTR_TO_RDWR_BUF_OR_NULL) {
reg->type = PTR_TO_RDWR_BUF;
}
if (is_null) {
/* We don't need id and ref_obj_id from this point
* onwards anymore, thus we should better reset it,
* so that state pruning has chances to take effect.
*/
reg->id = 0;
reg->ref_obj_id = 0;
} else if (!reg_may_point_to_spin_lock(reg)) {
return;
}
mark_ptr_not_null_reg(reg);
if (!reg_may_point_to_spin_lock(reg)) {
/* For not-NULL ptr, reg->ref_obj_id will be reset
* in release_reg_references().
*