netdev - [PATCH v4 bpf-next 02/14] bpf: Print multiple type flags in verifier log

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: <1dbc2df5bbfe0395ca9423cdce3fd8fc79f8e0ab.1653600578.git.lorenzo@kernel.org>
Date:   Thu, 26 May 2022 23:34:50 +0200
From:   Lorenzo Bianconi <lorenzo@...nel.org>
To:     bpf@...r.kernel.org
Cc:     netdev@...r.kernel.org, ast@...nel.org, daniel@...earbox.net,
        andrii@...nel.org, davem@...emloft.net, kuba@...nel.org,
        edumazet@...gle.com, pabeni@...hat.com, pablo@...filter.org,
        fw@...len.de, netfilter-devel@...r.kernel.org,
        lorenzo.bianconi@...hat.com, brouer@...hat.com, toke@...hat.com,
        memxor@...il.com, yhs@...com
Subject: [PATCH v4 bpf-next 02/14] bpf: Print multiple type flags in verifier log

From: Kumar Kartikeya Dwivedi <memxor@...il.com>

Since MEM_RDONLY and PTR_UNTRUSTED can be present together in register
type now, try to print multiple tags using the prefix buffer. Since
all 5 cannot be present together, 32 bytes is still enough room for
any possible combination. Instead of tracking the current position
into the buffer, simply rely on snprintf, which also ensures nul
termination.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@...il.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
---
 kernel/bpf/verifier.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index aedac2ac02b9..e0be76861736 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -564,16 +564,12 @@ static const char *reg_type_str(struct bpf_verifier_env *env,
 			strncpy(postfix, "_or_null", 16);
 	}
 
-	if (type & MEM_RDONLY)
-		strncpy(prefix, "rdonly_", 32);
-	if (type & MEM_ALLOC)
-		strncpy(prefix, "alloc_", 32);
-	if (type & MEM_USER)
-		strncpy(prefix, "user_", 32);
-	if (type & MEM_PERCPU)
-		strncpy(prefix, "percpu_", 32);
-	if (type & PTR_UNTRUSTED)
-		strncpy(prefix, "untrusted_", 32);
+	snprintf(prefix, sizeof(prefix), "%s%s%s%s%s",
+		 (type & MEM_RDONLY ? "rdonly_" : ""),
+		 (type & MEM_ALLOC ? "alloc_" : ""),
+		 (type & MEM_USER ? "user_" : ""),
+		 (type & MEM_PERCPU ? "percpu_" : ""),
+		 (type & PTR_UNTRUSTED ? "untrusted_" : ""));
 
 	snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s",
 		 prefix, str[base_type(type)], postfix);
-- 
2.35.3