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authorDaniel Borkmann <daniel@iogearbox.net>2018-10-24 22:05:49 +0200
committerAlexei Starovoitov <ast@kernel.org>2018-10-25 17:02:06 -0700
commitb09928b976280d64060d7bee146d7df5c5a29bef (patch)
tree56255e6f507f2685a1ff991502711cdbe5de20e9 /kernel
parentd3f66e4116aff8dd0d5bd4067295b9ddb5e2c29c (diff)
downloadlinux-b09928b976280d64060d7bee146d7df5c5a29bef.tar.bz2
bpf: make direct packet write unclone more robust
Given this seems to be quite fragile and can easily slip through the cracks, lets make direct packet write more robust by requiring that future program types which allow for such write must provide a prologue callback. In case of XDP and sk_msg it's noop, thus add a generic noop handler there. The latter starts out with NULL data/data_end unconditionally when sg pages are shared. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/verifier.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5fc9a658af0e..171a2c88e77d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5709,7 +5709,11 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
bool is_narrower_load;
u32 target_size;
- if (ops->gen_prologue) {
+ if (ops->gen_prologue || env->seen_direct_write) {
+ if (!ops->gen_prologue) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
env->prog);
if (cnt >= ARRAY_SIZE(insn_buf)) {