Merge tag 'fixes_for_v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull ext2 and udf fixes from Jan Kara:
 "Three small ext2 and udf fixes"

* tag 'fixes_for_v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: fix potential use after free
  ext2: initialize opts.s_mount_opt as zero before using it
  udf: Allow mounting volumes with incorrect identification strings

4 files changed, 23 insertions, 10 deletions

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index cb91baa4275d..eb11502e3fcd 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -892,6 +892,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	if (sb->s_magic != EXT2_SUPER_MAGIC)
 		goto cantfind_ext2;
 
+	opts.s_mount_opt = 0;
 	/* Set defaults before we parse the mount options */
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 	if (def_mount_opts & EXT2_DEFM_DEBUG)
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 62d9a659a8ff..dd8f10db82e9 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -612,9 +612,9 @@ skip_replace:
 	}
 
 cleanup:
-	brelse(bh);
 	if (!(bh && header == HDR(bh)))
 		kfree(header);
+	brelse(bh);
 	up_write(&EXT2_I(inode)->xattr_sem);
 
 	return error;
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 8f2f56d9a1bb..e3d684ea3203 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -827,16 +827,20 @@ static int udf_load_pvoldesc(struct super_block *sb, sector_t block)
 
 
 	ret = udf_dstrCS0toChar(sb, outstr, 31, pvoldesc->volIdent, 32);
-	if (ret < 0)
-		goto out_bh;
-
-	strncpy(UDF_SB(sb)->s_volume_ident, outstr, ret);
+	if (ret < 0) {
+		strcpy(UDF_SB(sb)->s_volume_ident, "InvalidName");
+		pr_warn("incorrect volume identification, setting to "
+			"'InvalidName'\n");
+	} else {
+		strncpy(UDF_SB(sb)->s_volume_ident, outstr, ret);
+	}
 	udf_debug("volIdent[] = '%s'\n", UDF_SB(sb)->s_volume_ident);
 
 	ret = udf_dstrCS0toChar(sb, outstr, 127, pvoldesc->volSetIdent, 128);
-	if (ret < 0)
+	if (ret < 0) {
+		ret = 0;
 		goto out_bh;
-
+	}
 	outstr[ret] = 0;
 	udf_debug("volSetIdent[] = '%s'\n", outstr);
 
diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index 45234791fec2..5fcfa96463eb 100644
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -351,6 +351,11 @@ 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_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len,
 		      const uint8_t *ocu_i, int i_len)
 {
@@ -359,9 +364,12 @@ int udf_dstrCS0toChar(struct super_block *sb, 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;
 		}
 	}