Add serial-number to hw.fdt sysctl area if found in fdt.

Add serial-number sysctl if that fdt property exists and is a printable
string.  While here, ensure that the hw.fdt sysctl values fit in the
buffers provided so that they will be NUL-terminated.  Tested on
Raspberry Pi 3B+ and 4.

Reviewed by:	manu imp
Differential Revision: https://reviews.freebsd.org/D34356

(cherry picked from commit b8b0c65e8a43cab95b97e28d3e3d73fc7d9c0a5e)

diff --git a/sys/dev/ofw/ofw_fdt.c b/sys/dev/ofw/ofw_fdt.c
index a83f7cbdcb6024e157cdb419d1498fe378a0fe8d..855bf6d5d14a45a35b9fc3b370f958a7539ac9c8 100644 (file)
--- a/sys/dev/ofw/ofw_fdt.c
+++ b/sys/dev/ofw/ofw_fdt.c
@@ -32,6 +32,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/ctype.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/systm.h>
@@ -107,11 +108,13 @@ OFW_DEF(ofw_fdt);
 #define        FDT_FBSDVER_LEN 16
 #define        FDT_MODEL_LEN   80
 #define        FDT_COMPAT_LEN  255
+#define        FDT_SERIAL_LEN  32
 
 static void *fdtp = NULL;
 static char fdt_model[FDT_MODEL_LEN];
 static char fdt_compatible[FDT_COMPAT_LEN];
 static char fdt_fbsd_version[FDT_FBSDVER_LEN];
+static char fdt_serial[FDT_SERIAL_LEN];
 
 static int
 sysctl_handle_dtb(SYSCTL_HANDLER_ARGS)
@@ -143,6 +146,10 @@ sysctl_register_fdt_oid(void *arg)
                SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
                    OID_AUTO, "freebsd-version", CTLFLAG_RD, fdt_fbsd_version,
                    FDT_FBSDVER_LEN, "FreeBSD DTS branding version");
+       if (fdt_serial[0] != '\0')
+               SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
+                   OID_AUTO, "serial-number", CTLFLAG_RD, fdt_serial,
+                   FDT_SERIAL_LEN, "Serial number");
 }
 SYSINIT(dtb_oid, SI_SUB_KMEM, SI_ORDER_ANY, sysctl_register_fdt_oid, NULL);
 
@@ -161,20 +168,44 @@ ofw_fdt_init(ofw_t ofw, void *data)
        fdtp = data;
        root = ofw_fdt_finddevice(NULL, "/");
        len = ofw_fdt_getproplen(NULL, root, "model");
-       bzero(fdt_model, FDT_MODEL_LEN);
-       ofw_fdt_getprop(NULL, root, "model", fdt_model, FDT_MODEL_LEN);
+       if (len > 0 && len <= FDT_MODEL_LEN) {
+               bzero(fdt_model, FDT_MODEL_LEN);
+               ofw_fdt_getprop(NULL, root, "model", fdt_model, FDT_MODEL_LEN);
+       }
        len = ofw_fdt_getproplen(NULL, root, "compatible");
-       bzero(fdt_compatible, FDT_COMPAT_LEN);
-       ofw_fdt_getprop(NULL, root, "compatible", fdt_compatible, FDT_COMPAT_LEN);
-       /* Replace the middle '\0' with ' ' */
-       for (i = 0; i < len - 1; i++)
-               if (fdt_compatible[i] == '\0')
-                       fdt_compatible[i] = ' ';
-       if ((len = ofw_fdt_getproplen(NULL, root, "freebsd,dts-version")) > 0) {
+       if (len > 0 && len <= FDT_COMPAT_LEN) {
+               bzero(fdt_compatible, FDT_COMPAT_LEN);
+               ofw_fdt_getprop(NULL, root, "compatible", fdt_compatible,
+                   FDT_COMPAT_LEN);
+               /* Replace the middle '\0' with ' ' */
+               for (i = 0; i < len - 1; i++)
+                       if (fdt_compatible[i] == '\0')
+                               fdt_compatible[i] = ' ';
+       }
+       len = ofw_fdt_getproplen(NULL, root, "freebsd,dts-version");
+       if (len > 0 && len <= FDT_FBSDVER_LEN) {
                bzero(fdt_fbsd_version, FDT_FBSDVER_LEN);
                ofw_fdt_getprop(NULL, root, "freebsd,dts-version",
                  fdt_fbsd_version, FDT_FBSDVER_LEN);
        }
+       len = ofw_fdt_getproplen(NULL, root, "serial-number");
+       if (len > 0 && len <= FDT_SERIAL_LEN) {
+               bzero(fdt_serial, FDT_SERIAL_LEN);
+               ofw_fdt_getprop(NULL, root, "serial-number",
+                   fdt_serial, FDT_SERIAL_LEN);
+               /*
+                * Non-standard property; check for NUL-terminated
+                * printable string.
+                */
+               for (i = 0; i < len - 1; i++) {
+                       if (!isprint(fdt_serial[i])) {
+                               fdt_serial[0] = '\0';
+                               break;
+                       }
+               }
+               if (fdt_serial[len - 1] != '\0')
+                       fdt_serial[0] = '\0';
+       }
        return (0);
 }