bpf: Move check_ptr_off_reg before check_map_access

Some functions in next patch want to use this function, and those
functions will be called by check_map_access, hence move it before
check_map_access.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/bpf/20220415160354.1050687-3-memxor@gmail.com

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9c1a02b..71827d1 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3469,6 +3469,44 @@ static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
        return 0;
 }
 
+static int __check_ptr_off_reg(struct bpf_verifier_env *env,
+                              const struct bpf_reg_state *reg, int regno,
+                              bool fixed_off_ok)
+{
+       /* Access to this pointer-typed register or passing it to a helper
+        * is only allowed in its original, unmodified form.
+        */
+
+       if (reg->off < 0) {
+               verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
+                       reg_type_str(env, reg->type), regno, reg->off);
+               return -EACCES;
+       }
+
+       if (!fixed_off_ok && reg->off) {
+               verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
+                       reg_type_str(env, reg->type), regno, reg->off);
+               return -EACCES;
+       }
+
+       if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+               char tn_buf[48];
+
+               tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+               verbose(env, "variable %s access var_off=%s disallowed\n",
+                       reg_type_str(env, reg->type), tn_buf);
+               return -EACCES;
+       }
+
+       return 0;
+}
+
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+                     const struct bpf_reg_state *reg, int regno)
+{
+       return __check_ptr_off_reg(env, reg, regno, false);
+}
+
 /* check read/write into a map element with possible variable offset */
 static int check_map_access(struct bpf_verifier_env *env, u32 regno,
                            int off, int size, bool zero_size_allowed)
@@ -3980,44 +4018,6 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env,
 }
 #endif
 
-static int __check_ptr_off_reg(struct bpf_verifier_env *env,
-                              const struct bpf_reg_state *reg, int regno,
-                              bool fixed_off_ok)
-{
-       /* Access to this pointer-typed register or passing it to a helper
-        * is only allowed in its original, unmodified form.
-        */
-
-       if (reg->off < 0) {
-               verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
-                       reg_type_str(env, reg->type), regno, reg->off);
-               return -EACCES;
-       }
-
-       if (!fixed_off_ok && reg->off) {
-               verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
-                       reg_type_str(env, reg->type), regno, reg->off);
-               return -EACCES;
-       }
-
-       if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
-               char tn_buf[48];
-
-               tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
-               verbose(env, "variable %s access var_off=%s disallowed\n",
-                       reg_type_str(env, reg->type), tn_buf);
-               return -EACCES;
-       }
-
-       return 0;
-}
-
-int check_ptr_off_reg(struct bpf_verifier_env *env,
-                     const struct bpf_reg_state *reg, int regno)
-{
-       return __check_ptr_off_reg(env, reg, regno, false);
-}
-
 static int __check_buffer_access(struct bpf_verifier_env *env,
                                 const char *buf_info,
                                 const struct bpf_reg_state *reg,