netdev - [PATCH v6 bpf-next 2/4] bpf: Support "%c" in bpf_bprintf

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]

Date:   Sat, 14 Aug 2021 10:57:16 +0900
From:   Kuniyuki Iwashima <kuniyu@...zon.co.jp>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        "Song Liu" <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>
CC:     Benjamin Herrenschmidt <benh@...zon.com>,
        Kuniyuki Iwashima <kuniyu@...zon.co.jp>,
        Kuniyuki Iwashima <kuni1840@...il.com>, <bpf@...r.kernel.org>,
        <netdev@...r.kernel.org>
Subject: [PATCH v6 bpf-next 2/4] bpf: Support "%c" in bpf_bprintf_prepare().

/proc/net/unix uses "%c" to print a single-byte character to escape '\0' in
the name of the abstract UNIX domain socket.  The following selftest uses
it, so this patch adds support for "%c".  Note that it does not support
wide character ("%lc" and "%llc") for simplicity.

Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.co.jp>
Acked-by: Yonghong Song <yhs@...com>
---
 kernel/bpf/helpers.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 32761be48143..4e8540716187 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -907,6 +907,20 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 			tmp_buf += err;
 			num_spec++;
 
+			continue;
+		} else if (fmt[i] == 'c') {
+			if (!tmp_buf)
+				goto nocopy_fmt;
+
+			if (tmp_buf_end == tmp_buf) {
+				err = -ENOSPC;
+				goto out;
+			}
+
+			*tmp_buf = raw_args[num_spec];
+			tmp_buf++;
+			num_spec++;
+
 			continue;
 		}
 
-- 
2.30.2