diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6515d4d3c003..9f1333676365 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5326,14 +5326,11 @@ static int check_max_stack_depth(struct bpf_verifier_env *env) static int __check_buffer_access(struct bpf_verifier_env *env, const char *buf_info, const struct bpf_reg_state *reg, - argno_t argno, int off, int size) + argno_t argno, int off, int size, + u32 *access_end) { - if (off < 0) { - verbose(env, - "%s invalid %s buffer access: off=%d, size=%d\n", - reg_arg_name(env, argno), buf_info, off, size); - return -EACCES; - } + s64 start; + if (!tnum_is_const(reg->var_off)) { char tn_buf[48]; @@ -5344,6 +5341,15 @@ static int __check_buffer_access(struct bpf_verifier_env *env, return -EACCES; } + start = (s64)reg->var_off.value + off; + if (start < 0) { + verbose(env, + "%s invalid negative %s buffer offset: off=%d, var_off=%lld\n", + reg_arg_name(env, argno), buf_info, off, (s64)reg->var_off.value); + return -EACCES; + } + + *access_end = start + size; return 0; } @@ -5351,14 +5357,14 @@ static int check_tp_buffer_access(struct bpf_verifier_env *env, const struct bpf_reg_state *reg, argno_t argno, int off, int size) { + u32 access_end; int err; - err = __check_buffer_access(env, "tracepoint", reg, argno, off, size); + err = __check_buffer_access(env, "tracepoint", reg, argno, off, size, &access_end); if (err) return err; - env->prog->aux->max_tp_access = max(reg->var_off.value + off + size, - env->prog->aux->max_tp_access); + env->prog->aux->max_tp_access = max(access_end, env->prog->aux->max_tp_access); return 0; } @@ -5370,13 +5376,14 @@ static int check_buffer_access(struct bpf_verifier_env *env, u32 *max_access) { const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr"; + u32 access_end; int err; - err = __check_buffer_access(env, buf_info, reg, argno, off, size); + err = __check_buffer_access(env, buf_info, reg, argno, off, size, &access_end); if (err) return err; - *max_access = max(reg->var_off.value + off + size, *max_access); + *max_access = max(access_end, *max_access); return 0; }