ima: fix showing large 'violations' or 'runtime_measurements_count'

BugLink: https://bugs.launchpad.net/bugs/1810947

commit 1e4c8daf upstream.

The 12 character temporary buffer is not necessarily long enough to hold
a 'long' value.  Increase it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

security/integrity/ima/ima_fs.c

@@ -26,14 +26,14 @@
 #include "ima.h"
 
 static int valid_policy = 1;
-#define TMPBUFLEN 12
+
 static ssize_t ima_show_htable_value(char __user *buf, size_t count,
 				     loff_t *ppos, atomic_long_t *val)
 {
-	char tmpbuf[TMPBUFLEN];
+	char tmpbuf[32];	/* greater than largest 'long' string value */
 	ssize_t len;
 
-	len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val));
+	len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val));
 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
 }