udf: Allow mounting volumes with incorrect identification strings

[mirror_ubuntu-bionic-kernel.git] / fs / udf / unicode.c

diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index f897e55f2cd07f57de7b01f2db92063ce7faa7a8..43e7ee13b5949037514bc1fa0ed0a428f9082add 100644 (file)
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -28,6 +28,9 @@
 
 #include "udf_sb.h"
 
+#define SURROGATE_MASK 0xfffff800
+#define SURROGATE_PAIR 0x0000d800
+
 static int udf_uni2char_utf8(wchar_t uni,
                             unsigned char *out,
                             int boundlen)
@@ -37,6 +40,9 @@ static int udf_uni2char_utf8(wchar_t uni,
        if (boundlen <= 0)
                return -ENAMETOOLONG;
 
+       if ((uni & SURROGATE_MASK) == SURROGATE_PAIR)
+               return -EINVAL;
+
        if (uni < 0x80) {
                out[u_len++] = (unsigned char)uni;
        } else if (uni < 0x800) {
@@ -335,6 +341,11 @@ try_again:
        return u_len;
 }
 
+/*
+ * Convert CS0 dstring to output charset. Warning: This function may truncate
+ * input string if it is too long as it is used for informational strings only
+ * and it is better to truncate the string than to refuse mounting a media.
+ */
 int udf_dstrCS0toUTF8(uint8_t *utf_o, int o_len,
                      const uint8_t *ocu_i, int i_len)
 {
@@ -343,9 +354,12 @@ int udf_dstrCS0toUTF8(uint8_t *utf_o, int o_len,
        if (i_len > 0) {
                s_len = ocu_i[i_len - 1];
                if (s_len >= i_len) {
-                       pr_err("incorrect dstring lengths (%d/%d)\n",
-                              s_len, i_len);
-                       return -EINVAL;
+                       pr_warn("incorrect dstring lengths (%d/%d),"
+                               " truncating\n", s_len, i_len);
+                       s_len = i_len - 1;
+                       /* 2-byte encoding? Need to round properly... */
+                       if (ocu_i[0] == 16)
+                               s_len -= (s_len - 1) & 2;
                }
        }