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bpf/verifier: Pass instruction index to check_mem_access() and check_xadd()

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Extracted from commit 31fd85816dbe "bpf: permits narrower load from
bpf program context fields".

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ben Hutchings 2018-12-05 22:41:36 +00:00 • committed by Greg Kroah-Hartman
parent 168cb9b7b2
commit 451624d470
1 changed files with 8 additions and 8 deletions
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16
kernel/bpf/verifier.c
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@ -694,7 +694,7 @@ static bool is_ctx_reg(struct verifier_env *env, int regno)
* 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 verifier_env *env, u32 regno, int off,
static int check_mem_access(struct verifier_env *env, int insn_idx, u32 regno, int off,
int bpf_size, enum bpf_access_type t,
int value_regno)
{
@ -758,7 +758,7 @@ static int check_mem_access(struct verifier_env *env, u32 regno, int off,
return err;
}
static int check_xadd(struct verifier_env *env, struct bpf_insn *insn)
static int check_xadd(struct verifier_env *env, int insn_idx, struct bpf_insn *insn)
{
struct reg_state *regs = env->cur_state.regs;
int err;
@ -791,13 +791,13 @@ static int check_xadd(struct verifier_env *env, struct bpf_insn *insn)
}
/* check whether atomic_add can read the memory */
err = check_mem_access(env, insn->dst_reg, insn->off,
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ, -1);
if (err)
return err;
/* check whether atomic_add can write into the same memory */
return check_mem_access(env, insn->dst_reg, insn->off,
return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE, -1);
}
@ -1836,7 +1836,7 @@ static int do_check(struct verifier_env *env)
/* check that memory (src_reg + off) is readable,
* the state of dst_reg will be updated by this func
*/
err = check_mem_access(env, insn->src_reg, insn->off,
err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ,
insn->dst_reg);
if (err)
@ -1875,7 +1875,7 @@ static int do_check(struct verifier_env *env)
enum bpf_reg_type *prev_dst_type, dst_reg_type;
if (BPF_MODE(insn->code) == BPF_XADD) {
err = check_xadd(env, insn);
err = check_xadd(env, insn_idx, insn);
if (err)
return err;
insn_idx++;
@ -1894,7 +1894,7 @@ static int do_check(struct verifier_env *env)
dst_reg_type = regs[insn->dst_reg].type;
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn->dst_reg, insn->off,
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
insn->src_reg);
if (err)
@ -1929,7 +1929,7 @@ static int do_check(struct verifier_env *env)
}
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn->dst_reg, insn->off,
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
-1);
if (err)