From ef66c5475d7fb864c2418d3bdd19dee46324624b Mon Sep 17 00:00:00 2001 From: David Vernet Date: Sat, 19 Nov 2022 23:10:01 -0600 Subject: bpf: Allow multiple modifiers in reg_type_str() prefix reg_type_str() in the verifier currently only allows a single register type modifier to be present in the 'prefix' string which is eventually stored in the env type_str_buf. This currently works fine because there are no overlapping type modifiers, but once PTR_TRUSTED is added, that will no longer be the case. This patch updates reg_type_str() to support having multiple modifiers in the prefix string, and updates the size of type_str_buf to be 128 bytes. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20221120051004.3605026-2-void@manifault.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 195d24316750..67a6f11d953c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -557,7 +557,7 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn) static const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) { - char postfix[16] = {0}, prefix[32] = {0}; + char postfix[16] = {0}, prefix[64] = {0}; static const char * const str[] = { [NOT_INIT] = "?", [SCALAR_VALUE] = "scalar", @@ -589,16 +589,13 @@ static const char *reg_type_str(struct bpf_verifier_env *env, strncpy(postfix, "_or_null", 16); } - if (type & MEM_RDONLY) - strncpy(prefix, "rdonly_", 32); - if (type & MEM_RINGBUF) - strncpy(prefix, "ringbuf_", 32); - if (type & MEM_USER) - strncpy(prefix, "user_", 32); - if (type & MEM_PERCPU) - strncpy(prefix, "percpu_", 32); - if (type & PTR_UNTRUSTED) - strncpy(prefix, "untrusted_", 32); + snprintf(prefix, sizeof(prefix), "%s%s%s%s%s", + type & MEM_RDONLY ? "rdonly_" : "", + type & MEM_RINGBUF ? "ringbuf_" : "", + type & MEM_USER ? "user_" : "", + type & MEM_PERCPU ? "percpu_" : "", + type & PTR_UNTRUSTED ? "untrusted_" : "" + ); snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s", prefix, str[base_type(type)], postfix); -- cgit v1.2.3