Unlike BPF to BPF function call, BPF helper call is calls to native insns that verifier can't walk. So, verifier needs helper proto type descriptions for data-flow purpose. There is such information already, but it is not differentiate sub-register read with full register read. This patch split "enum bpf_arg_type" for sub-register read, and updated descriptions for several functions that shown frequent usage in one Cilium benchmark. Reviewed-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> Signed-off-by: Jiong Wang <jiong.wang@xxxxxxxxxxxxx> --- include/linux/bpf.h | 3 +++ kernel/bpf/core.c | 2 +- kernel/bpf/helpers.c | 2 +- kernel/bpf/verifier.c | 19 +++++++++++++------ net/core/filter.c | 28 ++++++++++++++-------------- 5 files changed, 32 insertions(+), 22 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f628971..5616a58 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -190,9 +190,12 @@ enum bpf_arg_type { ARG_CONST_SIZE, /* number of bytes accessed from memory */ ARG_CONST_SIZE_OR_ZERO, /* number of bytes accessed from memory or 0 */ + ARG_CONST_SIZE32, /* Likewise, but size fits into 32-bit */ + ARG_CONST_SIZE32_OR_ZERO, /* Ditto */ ARG_PTR_TO_CTX, /* pointer to context */ ARG_ANYTHING, /* any (initialized) argument is ok */ + ARG_ANYTHING32, /* Likewise, but it is a 32-bit argument */ ARG_PTR_TO_SPIN_LOCK, /* pointer to bpf_spin_lock */ ARG_PTR_TO_SOCK_COMMON, /* pointer to sock_common */ }; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ff09d32..8834d80 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2065,7 +2065,7 @@ const struct bpf_func_proto bpf_tail_call_proto = { .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, - .arg3_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING32, }; /* Stub for JITs that only support cBPF. eBPF programs are interpreted. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a411fc1..6b7453e 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -218,7 +218,7 @@ const struct bpf_func_proto bpf_get_current_comm_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_UNINIT_MEM, - .arg2_type = ARG_CONST_SIZE, + .arg2_type = ARG_CONST_SIZE32, }; #if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 66e5e65..83448bb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2398,7 +2398,9 @@ static bool arg_type_is_mem_ptr(enum bpf_arg_type type) static bool arg_type_is_mem_size(enum bpf_arg_type type) { return type == ARG_CONST_SIZE || - type == ARG_CONST_SIZE_OR_ZERO; + type == ARG_CONST_SIZE_OR_ZERO || + type == ARG_CONST_SIZE32 || + type == ARG_CONST_SIZE32_OR_ZERO; } static int check_func_arg(struct bpf_verifier_env *env, u32 regno, @@ -2416,10 +2418,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, if (err) return err; - /* arg_type doesn't differentiate 32 and 64-bit arg, always zext. */ - mark_insn_zext(env, cur_func(env), regno); + if (arg_type != ARG_ANYTHING32 && + arg_type != ARG_CONST_SIZE32 && + arg_type != ARG_CONST_SIZE32_OR_ZERO) + mark_insn_zext(env, cur_func(env), regno); - if (arg_type == ARG_ANYTHING) { + if (arg_type == ARG_ANYTHING || arg_type == ARG_ANYTHING32) { if (is_pointer_value(env, regno)) { verbose(env, "R%d leaks addr into helper function\n", regno); @@ -2442,7 +2446,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, type != expected_type) goto err_type; } else if (arg_type == ARG_CONST_SIZE || - arg_type == ARG_CONST_SIZE_OR_ZERO) { + arg_type == ARG_CONST_SIZE_OR_ZERO || + arg_type == ARG_CONST_SIZE32 || + arg_type == ARG_CONST_SIZE32_OR_ZERO) { expected_type = SCALAR_VALUE; if (type != expected_type) goto err_type; @@ -2536,7 +2542,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, meta->map_ptr->value_size, false, meta); } else if (arg_type_is_mem_size(arg_type)) { - bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); + bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO || + arg_type == ARG_CONST_SIZE32_OR_ZERO); /* remember the mem_size which may be used later * to refine return values. diff --git a/net/core/filter.c b/net/core/filter.c index 22eb2ed..3f6d8af 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1693,9 +1693,9 @@ static const struct bpf_func_proto bpf_skb_store_bytes_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_PTR_TO_MEM, - .arg4_type = ARG_CONST_SIZE, + .arg4_type = ARG_CONST_SIZE32, .arg5_type = ARG_ANYTHING, }; @@ -1724,9 +1724,9 @@ static const struct bpf_func_proto bpf_skb_load_bytes_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_PTR_TO_UNINIT_MEM, - .arg4_type = ARG_CONST_SIZE, + .arg4_type = ARG_CONST_SIZE32, }; BPF_CALL_5(bpf_skb_load_bytes_relative, const struct sk_buff *, skb, @@ -1875,7 +1875,7 @@ static const struct bpf_func_proto bpf_l3_csum_replace_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING, .arg5_type = ARG_ANYTHING, @@ -1928,7 +1928,7 @@ static const struct bpf_func_proto bpf_l4_csum_replace_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING, .arg5_type = ARG_ANYTHING, @@ -1967,9 +1967,9 @@ static const struct bpf_func_proto bpf_csum_diff_proto = { .pkt_access = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_MEM_OR_NULL, - .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg2_type = ARG_CONST_SIZE32_OR_ZERO, .arg3_type = ARG_PTR_TO_MEM_OR_NULL, - .arg4_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_CONST_SIZE32_OR_ZERO, .arg5_type = ARG_ANYTHING, }; @@ -2150,7 +2150,7 @@ static const struct bpf_func_proto bpf_redirect_proto = { .func = bpf_redirect, .gpl_only = false, .ret_type = RET_INTEGER, - .arg1_type = ARG_ANYTHING, + .arg1_type = ARG_ANYTHING32, .arg2_type = ARG_ANYTHING, }; @@ -2928,7 +2928,7 @@ static const struct bpf_func_proto bpf_skb_change_proto_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_ANYTHING, }; @@ -2948,7 +2948,7 @@ static const struct bpf_func_proto bpf_skb_change_type_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, }; static u32 bpf_skb_net_base_len(const struct sk_buff *skb) @@ -3236,7 +3236,7 @@ static const struct bpf_func_proto bpf_skb_change_tail_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING32, .arg3_type = ARG_ANYTHING, }; @@ -3832,7 +3832,7 @@ static const struct bpf_func_proto bpf_skb_get_tunnel_key_proto = { .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_PTR_TO_UNINIT_MEM, - .arg3_type = ARG_CONST_SIZE, + .arg3_type = ARG_CONST_SIZE32, .arg4_type = ARG_ANYTHING, }; @@ -3941,7 +3941,7 @@ static const struct bpf_func_proto bpf_skb_set_tunnel_key_proto = { .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_PTR_TO_MEM, - .arg3_type = ARG_CONST_SIZE, + .arg3_type = ARG_CONST_SIZE32, .arg4_type = ARG_ANYTHING, }; -- 2.7.4