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bpf: cleanup register_is_null() 

don't pass large struct bpf_reg_state by value.
Instead pass it by pointer.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov 2017-11-30 21:31:40 -08:00 committed by Daniel Borkmann
parent 3bf15921c5
commit 914cb781ee
1 changed files with 10 additions and 10 deletions
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20
kernel/bpf/verifier.c
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@ -1265,9 +1265,9 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
}
/* Does this register contain a constant zero? */
static bool register_is_null(struct bpf_reg_state reg)
static bool register_is_null(struct bpf_reg_state *reg)
{
return reg.type == SCALAR_VALUE && tnum_equals_const(reg.var_off, 0);
return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
}
/* when register 'regno' is passed into function that will read 'access_size'
@ -1280,31 +1280,31 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
int access_size, bool zero_size_allowed,
struct bpf_call_arg_meta *meta)
{
struct bpf_reg_state *reg = cur_regs(env) + regno;
struct bpf_verifier_state *state = env->cur_state;
struct bpf_reg_state *regs = state->regs;
int off, i, slot, spi;
if (regs[regno].type != PTR_TO_STACK) {
if (reg->type != PTR_TO_STACK) {
/* Allow zero-byte read from NULL, regardless of pointer type */
if (zero_size_allowed && access_size == 0 &&
register_is_null(regs[regno]))
register_is_null(reg))
return 0;
verbose(env, "R%d type=%s expected=%s\n", regno,
reg_type_str[regs[regno].type],
reg_type_str[reg->type],
reg_type_str[PTR_TO_STACK]);
return -EACCES;
}
/* Only allow fixed-offset stack reads */
if (!tnum_is_const(regs[regno].var_off)) {
if (!tnum_is_const(reg->var_off)) {
char tn_buf[48];
tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off);
tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
verbose(env, "invalid variable stack read R%d var_off=%s\n",
regno, tn_buf);
}
off = regs[regno].off + regs[regno].var_off.value;
off = reg->off + reg->var_off.value;
if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
@ -1412,7 +1412,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
* passed in as argument, it's a SCALAR_VALUE type. Final test
* happens during stack boundary checking.
*/
if (register_is_null(*reg) &&
if (register_is_null(reg) &&
arg_type == ARG_PTR_TO_MEM_OR_NULL)
/* final test in check_stack_boundary() */;
else if (!type_is_pkt_pointer(type) &&