git: 292c814931d9 - main - MAC/do: sysctl_rules(): Always copy the rules specification string

The branch main has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=292c814931d975d56d5ffa7c3c85191d56a059c4

commit 292c814931d975d56d5ffa7c3c85191d56a059c4
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2024-07-03 12:52:38 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2024-12-16 14:42:34 +0000

    MAC/do: sysctl_rules(): Always copy the rules specification string
    
    We are not guaranteed that the 'rules' storage stays stable if we don't
    hold the prison lock.  For this reason, always copy the specification
    string (under the lock).
    
    Reviewed by:    bapt
    Approved by:    markj (mentor)
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D47600
---
 sys/security/mac_do/mac_do.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/sys/security/mac_do/mac_do.c b/sys/security/mac_do/mac_do.c
index ed4c984ff559..94fe7b99fc9d 100644
--- a/sys/security/mac_do/mac_do.c
+++ b/sys/security/mac_do/mac_do.c
@@ -309,30 +309,22 @@ parse_and_set_rules(struct prison *const pr, const char *rules_string)
 static int
 sysctl_rules(SYSCTL_HANDLER_ARGS)
 {
-	char *new_string;
+	char *const buf = malloc(MAC_RULE_STRING_LEN, M_DO, M_WAITOK);
 	struct prison *pr;
 	struct rules *rules;
 	int error;
 
 	rules = find_rules(req->td->td_ucred->cr_prison, &pr);
+	strlcpy(buf, rules->string, MAC_RULE_STRING_LEN);
 	prison_unlock(pr);
-	if (req->newptr == NULL)
-		return (sysctl_handle_string(oidp, rules->string, MAC_RULE_STRING_LEN, req));
 
-	new_string = malloc(MAC_RULE_STRING_LEN, M_DO,
-	    M_WAITOK|M_ZERO);
-	prison_lock(pr);
-	strlcpy(new_string, rules->string, MAC_RULE_STRING_LEN);
-	prison_unlock(pr);
-
-	error = sysctl_handle_string(oidp, new_string, MAC_RULE_STRING_LEN, req);
-	if (error)
+	error = sysctl_handle_string(oidp, buf, MAC_RULE_STRING_LEN, req);
+	if (error != 0 || req->newptr == NULL)
 		goto out;
 
-	error = parse_and_set_rules(pr, new_string);
-
+	error = parse_and_set_rules(pr, buf);
 out:
-	free(new_string, M_DO);
+	free(buf, M_DO);
 	return (error);
 }