This is a note to let you know that I've just added the patch titled
bpf: adjust insn_aux_data when patching insns
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-adjust-insn_aux_data-when-patching-insns.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Dec 22 16:57:35 CET 2017
From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Date: Fri, 22 Dec 2017 16:29:02 +0100
Subject: bpf: adjust insn_aux_data when patching insns
To: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: ast@xxxxxxxxxx, daniel@xxxxxxxxxxxxx, jannh@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, Alexei Starovoitov <ast@xxxxxx>, "David S . Miller" <davem@xxxxxxxxxxxxx>
Message-ID: <20171222152905.3455-2-daniel@xxxxxxxxxxxxx>
From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
From: Alexei Starovoitov <ast@xxxxxx>
[ Upstream commit 8041902dae5299c1f194ba42d14383f734631009 ]
convert_ctx_accesses() replaces single bpf instruction with a set of
instructions. Adjust corresponding insn_aux_data while patching.
It's needed to make sure subsequent 'for(all insn)' loops
have matching insn and insn_aux_data.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 44 +++++++++++++++++++++++++++++++++++++++-----
1 file changed, 39 insertions(+), 5 deletions(-)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3210,6 +3210,41 @@ static void convert_pseudo_ld_imm64(stru
insn->src_reg = 0;
}
+/* single env->prog->insni[off] instruction was replaced with the range
+ * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
+ * [0, off) and [off, end) to new locations, so the patched range stays zero
+ */
+static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len,
+ u32 off, u32 cnt)
+{
+ struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
+
+ if (cnt == 1)
+ return 0;
+ new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len);
+ if (!new_data)
+ return -ENOMEM;
+ memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
+ memcpy(new_data + off + cnt - 1, old_data + off,
+ sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
+ env->insn_aux_data = new_data;
+ vfree(old_data);
+ return 0;
+}
+
+static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
+ const struct bpf_insn *patch, u32 len)
+{
+ struct bpf_prog *new_prog;
+
+ new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
+ if (!new_prog)
+ return NULL;
+ if (adjust_insn_aux_data(env, new_prog->len, off, len))
+ return NULL;
+ return new_prog;
+}
+
/* convert load instructions that access fields of 'struct __sk_buff'
* into sequence of instructions that access fields of 'struct sk_buff'
*/
@@ -3229,10 +3264,10 @@ static int convert_ctx_accesses(struct b
verbose("bpf verifier is misconfigured\n");
return -EINVAL;
} else if (cnt) {
- new_prog = bpf_patch_insn_single(env->prog, 0,
- insn_buf, cnt);
+ new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
if (!new_prog)
return -ENOMEM;
+
env->prog = new_prog;
delta += cnt - 1;
}
@@ -3253,7 +3288,7 @@ static int convert_ctx_accesses(struct b
else
continue;
- if (env->insn_aux_data[i].ptr_type != PTR_TO_CTX)
+ if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX)
continue;
cnt = ops->convert_ctx_access(type, insn->dst_reg, insn->src_reg,
@@ -3263,8 +3298,7 @@ static int convert_ctx_accesses(struct b
return -EINVAL;
}
- new_prog = bpf_patch_insn_single(env->prog, i + delta, insn_buf,
- cnt);
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
if (!new_prog)
return -ENOMEM;
Patches currently in stable-queue which might be from daniel@xxxxxxxxxxxxx are
queue-4.9/bpf-fix-branch-pruning-logic.patch
queue-4.9/bpf-adjust-insn_aux_data-when-patching-insns.patch
queue-4.9/bpf-fix-incorrect-sign-extension-in-check_alu_op.patch
queue-4.9/bpf-reject-out-of-bounds-stack-pointer-calculation.patch