jfs: Fix uninit-value access of new_ea in ea_buffer

syzbot reports that lzo1x_1_do_compress is using uninit-value:

=====================================================
BUG: KMSAN: uninit-value in lzo1x_1_do_compress+0x19f9/0x2510 lib/lzo/lzo1x_compress.c:178

...

Uninit was stored to memory at:
 ea_put fs/jfs/xattr.c:639 [inline]

...

Local variable ea_buf created at:
 __jfs_setxattr+0x5d/0x1ae0 fs/jfs/xattr.c:662
 __jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:934

=====================================================

The reason is ea_buf->new_ea is not initialized properly.

Fix this by using memset to empty its content at the beginning
in ea_get().

Reported-by: syzbot+02341e0daa42a15ce130@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=02341e0daa42a15ce130
Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 2999ed5d83f5e082c3295bedc9beb2a12dce1b76..0fb05e314edf606f7b1265aee92a97403587944b 100644 (file)
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -434,6 +434,8 @@ static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
        int rc;
        int quota_allocation = 0;
 
+       memset(&ea_buf->new_ea, 0, sizeof(ea_buf->new_ea));
+
        /* When fsck.jfs clears a bad ea, it doesn't clear the size */
        if (ji->ea.flag == 0)
                ea_size = 0;