aboutsummaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
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 /net
parentd3f66e4116aff8dd0d5bd4067295b9ddb5e2c29c (diff)
downloadlinux-b09928b976280d64060d7bee146d7df5c5a29bef.tar.gz
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 'net')
-rw-r--r--net/core/filter.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 3fdddfa9a0fd..cd648d09a8e5 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5644,6 +5644,15 @@ static bool sock_filter_is_valid_access(int off, int size,
prog->expected_attach_type);
}
+static int bpf_noop_prologue(struct bpf_insn *insn_buf, bool direct_write,
+ const struct bpf_prog *prog)
+{
+ /* Neither direct read nor direct write requires any preliminary
+ * action.
+ */
+ return 0;
+}
+
static int bpf_unclone_prologue(struct bpf_insn *insn_buf, bool direct_write,
const struct bpf_prog *prog, int drop_verdict)
{
@@ -7210,6 +7219,7 @@ const struct bpf_verifier_ops xdp_verifier_ops = {
.get_func_proto = xdp_func_proto,
.is_valid_access = xdp_is_valid_access,
.convert_ctx_access = xdp_convert_ctx_access,
+ .gen_prologue = bpf_noop_prologue,
};
const struct bpf_prog_ops xdp_prog_ops = {
@@ -7308,6 +7318,7 @@ const struct bpf_verifier_ops sk_msg_verifier_ops = {
.get_func_proto = sk_msg_func_proto,
.is_valid_access = sk_msg_is_valid_access,
.convert_ctx_access = sk_msg_convert_ctx_access,
+ .gen_prologue = bpf_noop_prologue,
};
const struct bpf_prog_ops sk_msg_prog_ops = {