udf: Use separate buffer for copying split names

Code in udf_find_entry() and udf_readdir() used the same buffer for
storing filename that was split among blocks and for the resulting
filename in utf8. This worked because udf_get_filename() first
internally copied the name into a different buffer and only then
performed a conversion into the destination buffer. However we want to
get rid of intermediate buffers so use separate buffer for converted
name and name split between blocks so that we don't have the same source
and destination buffer when converting split names.

Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 11 insertions, 2 deletions

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 9eb9c6440270..a2ba11eca995 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -165,7 +165,7 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
 	struct fileIdentDesc *fi = NULL;
 	loff_t f_pos;
 	int block, flen;
-	unsigned char *fname = NULL;
+	unsigned char *fname = NULL, *copy_name = NULL;
 	unsigned char *nameptr;
 	uint8_t lfi;
 	uint16_t liu;
@@ -236,7 +236,15 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
 				nameptr = (uint8_t *)(fibh->ebh->b_data +
 						      poffset - lfi);
 			else {
-				nameptr = fname;
+				if (!copy_name) {
+					copy_name = kmalloc(UDF_NAME_LEN,
+							    GFP_NOFS);
+					if (!copy_name) {
+						fi = ERR_PTR(-ENOMEM);
+						goto out_err;
+					}
+				}
+				nameptr = copy_name;
 				memcpy(nameptr, fi->fileIdent + liu,
 					lfi - poffset);
 				memcpy(nameptr + lfi - poffset,
@@ -279,6 +287,7 @@ out_err:
 out_ok:
 	brelse(epos.bh);
 	kfree(fname);
+	kfree(copy_name);
 
 	return fi;
 }