netdev - [RFC PATCH bpf-next 10/12] bpf/verifier: parent state pointer is not per-frame

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <303a5d8c-beb6-5a87-e6a8-3f19adabbb88@solarflare.com>
Date:   Fri, 23 Feb 2018 17:42:07 +0000
From:   Edward Cree <ecree@...arflare.com>
To:     netdev <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: [RFC PATCH bpf-next 10/12] bpf/verifier: parent state pointer is not
 per-frame

Computing min_frame in find_loop and using it to detect recursion means we
 don't need to play games with per-frame parent pointers, and can instead
 have a single parent pointer in the verifier_state.

Signed-off-by: Edward Cree <ecree@...arflare.com>
---
 include/linux/bpf_verifier.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index ee034232fbd6..0320df10555b 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -121,12 +121,6 @@ struct bpf_func_state {
 	 */
 	u32 subprogno;
 
-	/* loop detection; points into an explored_state */
-	struct bpf_func_state *parent;
-	/* These flags are only meaningful in an explored_state, not cur_state */
-	bool bounded_loop, conditional;
-	int live_children;
-
 	/* should be second to last. See copy_func_state() */
 	int allocated_stack;
 	struct bpf_stack_state *stack;
@@ -137,6 +131,12 @@ struct bpf_verifier_state {
 	/* call stack tracking */
 	struct bpf_func_state *frame[MAX_CALL_FRAMES];
 	u32 curframe;
+
+	/* loop detection; points into an explored_state */
+	struct bpf_verifier_state *parent;
+	/* These flags are only meaningful in an explored_state, not cur_state */
+	bool bounded_loop, conditional;
+	int live_children;
 };
 
 /* linked list of verifier states used to prune search */