netdev - [PATCH bpf-next] libbpf: fix BTF-defined map's _

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-next>] [day] [month] [year] [list]

Message-ID: <20191004040211.2434033-1-andriin@fb.com>
Date:   Thu, 3 Oct 2019 21:02:11 -0700
From:   Andrii Nakryiko <andriin@...com>
To:     <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, <ast@...com>,
        <daniel@...earbox.net>
CC:     <andrii.nakryiko@...il.com>, <kernel-team@...com>,
        Andrii Nakryiko <andriin@...com>
Subject: [PATCH bpf-next] libbpf: fix BTF-defined map's __type macro handling of arrays

Due to a quirky C syntax of declaring pointers to array or function
prototype, existing __type() macro doesn't work with map key/value types
that are array or function prototype. One has to create a typedef first
and use it to specify key/value type for a BPF map.  By using typeof(),
pointer to type is now handled uniformly for all kinds of types. Convert
one of self-tests as a demonstration.

Signed-off-by: Andrii Nakryiko <andriin@...com>
---

N.B. This patch depends on patch set that moves bpf_helpers.h into libbpf to
avoid conflicts.

 tools/lib/bpf/bpf_helpers.h                              | 2 +-
 tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 2d3d1f51cdd0..6f68e4d3aff7 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -3,7 +3,7 @@
 #define __BPF_HELPERS__
 
 #define __uint(name, val) int (*name)[val]
-#define __type(name, val) val *name
+#define __type(name, val) typeof(val) *name
 
 /* Helper macro to print out debug messages */
 #define bpf_printk(fmt, ...)				\
diff --git a/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c b/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c
index f8ffa3f3d44b..6cc4479ac9df 100644
--- a/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c
+++ b/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c
@@ -47,12 +47,11 @@ struct {
  * issue and avoid complicated C programming massaging.
  * This is an acceptable workaround since there is one entry here.
  */
-typedef __u64 raw_stack_trace_t[2 * MAX_STACK_RAWTP];
 struct {
 	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
 	__uint(max_entries, 1);
 	__type(key, __u32);
-	__type(value, raw_stack_trace_t);
+	__type(value, __u64[2 * MAX_STACK_RAWTP]);
 } rawdata_map SEC(".maps");
 
 SEC("raw_tracepoint/sys_enter")
-- 
2.17.1