[PATCH 5.18 0475/1095] bpf: Move check_ptr_off_reg before check_map_access

Greg Kroah-Hartman
2022-08-15T21:18:49Z

From: Kumar Kartikeya Dwivedi <memxor@gmail.com>

[ Upstream commit e9147b4422e1f35b9c229c980c596ccf03d61562 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/bpf/verifier.c | 76 +++++++++++++++++++++----------------------
1 file changed, 38 insertions(+), 38 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f29aa357826c..afa05e6cd78f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3468,6 +3468,44 @@ 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)
@@ -3979,44 +4017,6 @@ 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,
--
2.35.1