1 files changed, 78 insertions, 5 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c3f36d415bdf..0e337541f005 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -655,6 +655,50 @@ char *resource_string(char *buf, char *end, struct resource *res,
 }
 
 static noinline_for_stack
+char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
+                 const char *fmt)
+{
+        int i, len = 1;         /* if we pass '%ph[CDN]', field witdh remains
+                                   negative value, fallback to the default */
+        char separator;
+
+        if (spec.field_width == 0)
+                /* nothing to print */
+                return buf;
+
+        if (ZERO_OR_NULL_PTR(addr))
+                /* NULL pointer */
+                return string(buf, end, NULL, spec);
+
+        switch (fmt[1]) {
+        case 'C':
+                separator = ':';
+                break;
+        case 'D':
+                separator = '-';
+                break;
+        case 'N':
+                separator = 0;
+                break;
+        default:
+                separator = ' ';
+                break;
+        }
+
+        if (spec.field_width > 0)
+                len = min_t(int, spec.field_width, 64);
+
+        for (i = 0; i < len && buf < end - 1; i++) {
+                buf = hex_byte_pack(buf, addr[i]);
+
+                if (buf < end && separator && i != len - 1)
+                        *buf++ = separator;
+        }
+
+        return buf;
+}
+
+static noinline_for_stack
 char *mac_address_string(char *buf, char *end, u8 *addr,
                          struct printf_spec spec, const char *fmt)
 {
@@ -662,15 +706,28 @@ char *mac_address_string(char *buf, char *end, u8 *addr,
         char *p = mac_addr;
         int i;
         char separator;
+        bool reversed = false;
 
-        if (fmt[1] == 'F') {            /* FDDI canonical format */
+        switch (fmt[1]) {
+        case 'F':
                 separator = '-';
-        } else {
+                break;
+
+        case 'R':
+                reversed = true;
+                /* fall through */
+
+        default:
                 separator = ':';
+                break;
         }
 
         for (i = 0; i < 6; i++) {
-                p = hex_byte_pack(p, addr[i]);
+                if (reversed)
+                        p = hex_byte_pack(p, addr[5 - i]);
+                else
+                        p = hex_byte_pack(p, addr[i]);
+
                 if (fmt[0] == 'M' && i != 5)
                         *p++ = separator;
         }
@@ -933,6 +990,7 @@ int kptr_restrict __read_mostly;
  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
  *       with a dash-separated hex notation
+ * - '[mM]R For a 6-byte MAC address, Reverse order (Bluetooth)
  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
@@ -960,6 +1018,13 @@ int kptr_restrict __read_mostly;
  *       correctness of the format string and va_list arguments.
  * - 'K' For a kernel pointer that should be hidden from unprivileged users
  * - 'NF' For a netdev_features_t
+ * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
+ *            a certain separator (' ' by default):
+ *              C colon
+ *              D dash
+ *              N no separator
+ *            The maximum supported length is 64 bytes of the input. Consider
+ *            to use print_hex_dump() for the larger input.
  *
  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
  * function pointers are really function descriptors, which contain a
@@ -993,9 +1058,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
         case 'R':
         case 'r':
                 return resource_string(buf, end, ptr, spec, fmt);
+        case 'h':
+                return hex_string(buf, end, ptr, spec, fmt);
         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
         case 'm':                       /* Contiguous: 000102030405 */
-                                        /* [mM]F (FDDI, bit reversed) */
+                                        /* [mM]F (FDDI) */
+                                        /* [mM]R (Reverse order; Bluetooth) */
                 return mac_address_string(buf, end, ptr, spec, fmt);
         case 'I':                       /* Formatted IP supported
                                          * 4:   1.2.3.4
@@ -1030,7 +1098,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
                  * %pK cannot be used in IRQ context because its test
                  * for CAP_SYSLOG would be meaningless.
                  */
-                if (in_irq() || in_serving_softirq() || in_nmi()) {
+                if (kptr_restrict && (in_irq() || in_serving_softirq() ||
+                                      in_nmi())) {
                         if (spec.field_width == -1)
                                 spec.field_width = default_width;
                         return string(buf, end, "pK-error", spec);
@@ -1280,8 +1349,12 @@ qualifier:
  * %pI6c print an IPv6 address as specified by RFC 5952
  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
  *   case.
+ * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
+ *           bytes of the input)
  * %n is ignored
  *
+ * ** Please update Documentation/printk-formats.txt when making changes **
+ *
  * The return value is the number of characters which would
  * be generated for the given input, excluding the trailing
  * '\0', as per ISO C99. If you want to have the exact