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-rw-r--r--kernel/bpf/verifier.c42
1 files changed, 26 insertions, 16 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5fb69a8..c6eff10 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1356,6 +1356,13 @@ static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
return reg->type == PTR_TO_CTX;
}
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = cur_regs(env) + regno;
+
+ return type_is_pkt_pointer(reg->type);
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -1416,10 +1423,10 @@ static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
}
static int check_ptr_alignment(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg,
- int off, int size)
+ const struct bpf_reg_state *reg, int off,
+ int size, bool strict_alignment_once)
{
- bool strict = env->strict_alignment;
+ bool strict = env->strict_alignment || strict_alignment_once;
const char *pointer_desc = "";
switch (reg->type) {
@@ -1576,9 +1583,9 @@ static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
* if t==write && value_regno==-1, some unknown value is stored into memory
* if t==read && value_regno==-1, don't care what we read from memory
*/
-static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, int off,
- int bpf_size, enum bpf_access_type t,
- int value_regno)
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+ int off, int bpf_size, enum bpf_access_type t,
+ int value_regno, bool strict_alignment_once)
{
struct bpf_reg_state *regs = cur_regs(env);
struct bpf_reg_state *reg = regs + regno;
@@ -1590,7 +1597,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
return size;
/* alignment checks will add in reg->off themselves */
- err = check_ptr_alignment(env, reg, off, size);
+ err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
if (err)
return err;
@@ -1735,21 +1742,23 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
return -EACCES;
}
- if (is_ctx_reg(env, insn->dst_reg)) {
- verbose(env, "BPF_XADD stores into R%d context is not allowed\n",
- insn->dst_reg);
+ if (is_ctx_reg(env, insn->dst_reg) ||
+ is_pkt_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
+ insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
+ "context" : "packet");
return -EACCES;
}
/* check whether atomic_add can read the memory */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_READ, -1);
+ BPF_SIZE(insn->code), BPF_READ, -1, true);
if (err)
return err;
/* check whether atomic_add can write into the same memory */
return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_WRITE, -1);
+ BPF_SIZE(insn->code), BPF_WRITE, -1, true);
}
/* when register 'regno' is passed into function that will read 'access_size'
@@ -2388,7 +2397,8 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
* is inferred from register state.
*/
for (i = 0; i < meta.access_size; i++) {
- err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1);
+ err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+ BPF_WRITE, -1, false);
if (err)
return err;
}
@@ -4632,7 +4642,7 @@ static int do_check(struct bpf_verifier_env *env)
*/
err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ,
- insn->dst_reg);
+ insn->dst_reg, false);
if (err)
return err;
@@ -4684,7 +4694,7 @@ static int do_check(struct bpf_verifier_env *env)
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- insn->src_reg);
+ insn->src_reg, false);
if (err)
return err;
@@ -4719,7 +4729,7 @@ static int do_check(struct bpf_verifier_env *env)
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- -1);
+ -1, false);
if (err)
return err;
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