[PATCH v1 1/2] lsm: Preserve full ioctl commands in audit records

[Mickaël Salaün]

Ioctl commands are unsigned int values, with their encoded direction and
size in the upper 16 bits.  However, struct lsm_ioctlop_audit keeps only
a u16, and the common audit formatter uses %hx.  This logs 0xc00ffeee as
0xfeee and makes distinct commands with matching low 16 bits
indistinguishable.

Change cmd to unsigned int and use %x.  Pass the full command through
ioctl_has_perm() as well.  Its driver and xperm values remain u8 values
derived from the same low 16 bits, so SELinux enforcement does not
change.  Commands that fit in 16 bits keep the same audit text.

Cc: Jeff Vander Stoep <jeffv at google.com>
Cc: Paul Moore <paul at paul-moore.com>
Cc: stable at vger.kernel.org
Fixes: 671a2781ff01 ("security: add ioctl specific auditing to lsm_audit")
Signed-off-by: Mickaël Salaün <mic at digikod.net>
---
 include/linux/lsm_audit.h | 2 +-
 security/lsm_audit.c      | 2 +-
 security/selinux/hooks.c  | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index 584db296e43b..fc68ca94f05a 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -44,7 +44,7 @@ struct lsm_network_audit {
 
 struct lsm_ioctlop_audit {
 	struct path path;
-	u16 cmd;
+	unsigned int cmd;
 };
 
 struct lsm_ibpkey_audit {
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 737f5a263a8f..a7891a75d0aa 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -231,7 +231,7 @@ void audit_log_lsm_data(struct audit_buffer *ab,
 			audit_log_format(ab, " ino=%llu", inode->i_ino);
 		}
 
-		audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd);
+		audit_log_format(ab, " ioctlcmd=0x%x", a->u.op->cmd);
 		break;
 	}
 	case LSM_AUDIT_DATA_DENTRY: {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 035aaf113d1d..e3eaa3141d91 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3859,7 +3859,7 @@ static int selinux_backing_file_alloc(struct file *backing_file,
  * operation to an inode.
  */
 static int ioctl_has_perm(const struct cred *cred, struct file *file,
-		u32 requested, u16 cmd)
+		u32 requested, unsigned int cmd)
 {
 	struct common_audit_data ad;
 	struct file_security_struct *fsec = selinux_file(file);
@@ -3930,14 +3930,14 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd,
 	case FIOCLEX:
 	case FIONCLEX:
 		if (!selinux_policycap_ioctl_skip_cloexec())
-			error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd);
+			error = ioctl_has_perm(cred, file, FILE__IOCTL, cmd);
 		break;
 
 	/* default case assumes that the command will go
 	 * to the file's ioctl() function.
 	 */
 	default:
-		error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd);
+		error = ioctl_has_perm(cred, file, FILE__IOCTL, cmd);
 	}
 	return error;
 }
-- 
2.55.0