netdev - [PATCH v4 bpf-next 1/9] bpf: merge printk and seq

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: <20210902171929.3922667-2-davemarchevsky@fb.com>
Date:   Thu, 2 Sep 2021 10:19:21 -0700
From:   Dave Marchevsky <davemarchevsky@...com>
To:     <bpf@...r.kernel.org>
CC:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Yonghong Song <yhs@...com>, <netdev@...r.kernel.org>,
        Dave Marchevsky <davemarchevsky@...com>
Subject: [PATCH v4 bpf-next 1/9] bpf: merge printk and seq_printf VARARG max macros

MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers
bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into
bpf_bprintf_prepare for print formatting logic and have convenience
macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same
helper macros to convert varargs to a byte array.

Changing shared functionality to support more varargs for either bpf
helper would affect the other as well, so let's combine the _VARARGS
macros to make this more obvious.

Signed-off-by: Dave Marchevsky <davemarchevsky@...com>
Acked-by: Andrii Nakryiko <andrii@...nel.org>
---
 include/linux/bpf.h      | 2 ++
 kernel/bpf/helpers.c     | 4 +---
 kernel/trace/bpf_trace.c | 4 +---
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f4c16f19f83e..be8d57e6e78a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2216,6 +2216,8 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 struct btf_id_set;
 bool btf_id_set_contains(const struct btf_id_set *set, u32 id);
 
+#define MAX_BPRINTF_VARARGS		12
+
 int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 			u32 **bin_buf, u32 num_args);
 void bpf_bprintf_cleanup(void);
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 9aabf84afd4b..8f9f392c1322 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -979,15 +979,13 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 	return err;
 }
 
-#define MAX_SNPRINTF_VARARGS		12
-
 BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
 	   const void *, data, u32, data_len)
 {
 	int err, num_args;
 	u32 *bin_args;
 
-	if (data_len % 8 || data_len > MAX_SNPRINTF_VARARGS * 8 ||
+	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
 	    (data_len && !data))
 		return -EINVAL;
 	num_args = data_len / 8;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 8e2eb950aa82..10672ebc63b7 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -414,15 +414,13 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 	return &bpf_trace_printk_proto;
 }
 
-#define MAX_SEQ_PRINTF_VARARGS		12
-
 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
 	   const void *, data, u32, data_len)
 {
 	int err, num_args;
 	u32 *bin_args;
 
-	if (data_len & 7 || data_len > MAX_SEQ_PRINTF_VARARGS * 8 ||
+	if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 ||
 	    (data_len && !data))
 		return -EINVAL;
 	num_args = data_len / 8;
-- 
2.30.2