lkml.org 
[lkml]   [2024]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH 5.15.y 2/5] bpf: Generalize check_ctx_reg for reuse with other types
From
From: Daniel Borkmann <daniel@iogearbox.net>

Generalize the check_ctx_reg() helper function into a more generic named one
so that it can be reused for other register types as well to check whether
their offset is non-zero. No functional change.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
(cherry picked from commit be80a1d3f9dbe5aee79a325964f7037fe2d92f30)
Signed-off-by: Edward Liaw <edliaw@google.com>
---
include/linux/bpf_verifier.h | 4 ++--
kernel/bpf/btf.c | 2 +-
kernel/bpf/verifier.c | 21 +++++++++++----------
3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 3d04b48e502d..c0993b079ab5 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -541,8 +541,8 @@ bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
void
bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt);

-int check_ctx_reg(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg, int regno);
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno);
int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
u32 regno, u32 mem_size);

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index b02f074363dd..2f6dc3fd06bb 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5553,7 +5553,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
i, btf_type_str(t));
return -EINVAL;
}
- if (check_ctx_reg(env, reg, regno))
+ if (check_ptr_off_reg(env, reg, regno))
return -EINVAL;
} else if (is_kfunc && (reg->type == PTR_TO_BTF_ID || reg2btf_ids[reg->type])) {
const struct btf_type *reg_ref_t;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1c95d97e7aa5..61b8a9c69b1c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3792,16 +3792,16 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env,
}
#endif

-int check_ctx_reg(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg, int regno)
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno)
{
- /* Access to ctx or passing it to a helper is only allowed in
- * its original, unmodified form.
+ /* Access to this pointer-typed register or passing it to a helper
+ * is only allowed in its original, unmodified form.
*/

if (reg->off) {
- verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n",
- regno, 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;
}

@@ -3809,7 +3809,8 @@ int check_ctx_reg(struct bpf_verifier_env *env,
char tn_buf[48];

tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
- verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf);
+ verbose(env, "variable %s access var_off=%s disallowed\n",
+ reg_type_str(env, reg->type), tn_buf);
return -EACCES;
}

@@ -4260,7 +4261,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
return -EACCES;
}

- err = check_ctx_reg(env, reg, regno);
+ err = check_ptr_off_reg(env, reg, regno);
if (err < 0)
return err;

@@ -5140,7 +5141,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
return err;

if (type == PTR_TO_CTX) {
- err = check_ctx_reg(env, reg, regno);
+ err = check_ptr_off_reg(env, reg, regno);
if (err < 0)
return err;
}
@@ -9348,7 +9349,7 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
return err;
}

- err = check_ctx_reg(env, &regs[ctx_reg], ctx_reg);
+ err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
if (err < 0)
return err;

--
2.44.0.769.g3c40516874-goog

\
 
 \ /
  Last update: 2024-04-18 01:37    [W:0.126 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site