udf: Fix memory corruption when fs mounted with noadinicb option
When UDF filesystem is mounted with noadinicb mount option, it
happens that we extend an empty directory with a block. A code in
udf_add_entry() didn't count with this possibility and used
uninitialized data leading to memory and filesystem corruption.
Add a check whether file already has some extents before operating
on them.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 47a6589..3d94bc1 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -315,7 +315,7 @@
uint16_t liu;
int block;
kernel_lb_addr eloc;
- uint32_t elen;
+ uint32_t elen = 0;
sector_t offset;
struct extent_position epos = {};
struct udf_inode_info *dinfo;
@@ -406,7 +406,8 @@
}
add:
- if (dinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
+ /* Is there any extent whose size we need to round up? */
+ if (dinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB && elen) {
elen = (elen + sb->s_blocksize - 1) & ~(sb->s_blocksize - 1);
if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
epos.offset -= sizeof(short_ad);
