git: 3bdc5ba2ac76 - main - MAC: syscalls: mac_label_copyin(): 32-bit compatibility

The branch main has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=3bdc5ba2ac760634056c66c3c98b6b3452258a5b

commit 3bdc5ba2ac760634056c66c3c98b6b3452258a5b
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2024-12-02 10:23:18 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2024-12-16 14:42:29 +0000

    MAC: syscalls: mac_label_copyin(): 32-bit compatibility
    
    Needed by the upcoming setcred() system call.  More generally, is a step
    on the way to support 32-bit compatibility for MAC-related system calls.
    
    Reviewed by:    brooks
    Approved by:    markj (mentor)
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D47878
---
 sys/security/mac/mac_syscalls.c | 50 ++++++++++++++++++++++++++++++++++++-----
 sys/security/mac/mac_syscalls.h |  7 ++++++
 2 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/sys/security/mac/mac_syscalls.c b/sys/security/mac/mac_syscalls.c
index e97a7dc09700..26181781a394 100644
--- a/sys/security/mac/mac_syscalls.c
+++ b/sys/security/mac/mac_syscalls.c
@@ -46,6 +46,7 @@
 #include "opt_mac.h"
 
 #include <sys/param.h>
+#include <sys/abi_compat.h>
 #include <sys/capsicum.h>
 #include <sys/fcntl.h>
 #include <sys/kernel.h>
@@ -79,6 +80,13 @@ static int	kern___mac_get_path(struct thread *td, const char *path_p,
 static int	kern___mac_set_path(struct thread *td, const char *path_p,
 		    struct mac *mac_p, int follow);
 
+#ifdef COMPAT_FREEBSD32
+struct mac32 {
+	uint32_t	m_buflen;	/* size_t */
+	uint32_t	m_string;	/* char * */
+};
+#endif
+
 /*
  * Copyin a 'struct mac', including the string pointed to by 'm_string'.
  *
@@ -86,16 +94,30 @@ static int	kern___mac_set_path(struct thread *td, const char *path_p,
  * after use by calling free_copied_label() (which see).  On success, 'u_string'
  * if not NULL is filled with the userspace address for 'u_mac->m_string'.
  */
-int
-mac_label_copyin(const struct mac *const u_mac, struct mac *const mac,
-    char **const u_string)
+static int
+mac_label_copyin_impl(const void *const u_mac, struct mac *const mac,
+    char **const u_string, bool is_32bit)
 {
 	char *buffer;
 	int error;
 
-	error = copyin(u_mac, mac, sizeof(*mac));
-	if (error != 0)
-		return (error);
+#ifdef COMPAT_FREEBSD32
+	if (is_32bit) {
+		struct mac32 mac32;
+
+		error = copyin(u_mac, &mac32, sizeof(mac32));
+		if (error != 0)
+			return (error);
+
+		CP(mac32, *mac, m_buflen);
+		PTRIN_CP(mac32, *mac, m_string);
+	} else
+#endif
+	{
+		error = copyin(u_mac, mac, sizeof(*mac));
+		if (error != 0)
+			return (error);
+	}
 
 	error = mac_check_structmac_consistent(mac);
 	if (error != 0)
@@ -116,12 +138,28 @@ mac_label_copyin(const struct mac *const u_mac, struct mac *const mac,
 	return (0);
 }
 
+int
+mac_label_copyin(const struct mac *const u_mac, struct mac *const mac,
+    char **const u_string)
+{
+	return (mac_label_copyin_impl(u_mac, mac, u_string, false));
+}
+
 void
 free_copied_label(const struct mac *const mac)
 {
 	free(mac->m_string, M_MACTEMP);
 }
 
+#ifdef COMPAT_FREEBSD32
+int
+mac_label_copyin32(const struct mac32 *const u_mac,
+    struct mac *const mac, char **const u_string)
+{
+	return (mac_label_copyin_impl(u_mac, mac, u_string, true));
+}
+#endif
+
 int
 sys___mac_get_pid(struct thread *td, struct __mac_get_pid_args *uap)
 {
diff --git a/sys/security/mac/mac_syscalls.h b/sys/security/mac/mac_syscalls.h
index 37445eafe364..4efeaf300d31 100644
--- a/sys/security/mac/mac_syscalls.h
+++ b/sys/security/mac/mac_syscalls.h
@@ -23,6 +23,13 @@ int	mac_label_copyin(const struct mac *const u_mac, struct mac *const mac,
 	    char **const u_string);
 void	free_copied_label(const struct mac *const mac);
 
+#ifdef COMPAT_FREEBSD32
+struct mac32;
+
+int	mac_label_copyin32(const struct mac32 *const u_mac,
+	    struct mac *const mac, char **const u_string);
+#endif /* COMPAT_FREEBSD32 */
+
 int	mac_set_proc_prepare(struct thread *const td,
 	    const struct mac *const mac, void **const mac_set_proc_data);
 int	mac_set_proc_core(struct thread *const td, struct ucred *const newcred,