From: Kaitao Cheng <chengkaitao@kylinos.cn>
Date: Tue, 19 May 2026 13:01:17 +0000 (+0800)
Subject: lib/vsprintf: Require exact hash_pointers mode matches
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b09b6d0c404d62480dbc23865c763c63598511f5;p=thirdparty%2Flinux.git

lib/vsprintf: Require exact hash_pointers mode matches

hash_pointers= accepts a small set of mode strings, but the parser uses
strncmp() with the length of each valid mode.  That accepts values with
trailing garbage, such as hash_pointers=autobots or
hash_pointers=nevermind, as valid aliases for auto and never.

Use strcmp() so that only the documented mode strings are accepted.
Invalid values will continue to fall back to auto through the existing
unknown-mode path.

Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20260519130117.48097-1-kaitao.cheng@linux.dev
Signed-off-by: Petr Mladek <pmladek@suse.com>
---

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d700dd0a52610..90b267b59254a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2362,13 +2362,13 @@ static int __init hash_pointers_mode_parse(char *str)
 	if (!str) {
 		pr_warn("Hash pointers mode empty; falling back to auto.\n");
 		hash_pointers_mode = HASH_PTR_AUTO;
-	} else if (strncmp(str, "auto", 4) == 0)   {
+	} else if (strcmp(str, "auto") == 0) {
 		pr_info("Hash pointers mode set to auto.\n");
 		hash_pointers_mode = HASH_PTR_AUTO;
-	} else if (strncmp(str, "never", 5) == 0) {
+	} else if (strcmp(str, "never") == 0) {
 		pr_info("Hash pointers mode set to never.\n");
 		hash_pointers_mode = HASH_PTR_NEVER;
-	} else if (strncmp(str, "always", 6) == 0) {
+	} else if (strcmp(str, "always") == 0) {
 		pr_info("Hash pointers mode set to always.\n");
 		hash_pointers_mode = HASH_PTR_ALWAYS;
 	} else {