From c2c3d86bd4a99a9d0a4d2087574d71a8071ef245 Mon Sep 17 00:00:00 2001 From: Yuezhang Mo Date: Thu, 22 Sep 2022 14:43:47 +0800 Subject: [PATCH] exfat: fix unexpected EOF while reading dir commit 6cb5d1a16a51d080fbc1649a5144cbc5ca7d6f88 upstream. If the position is not aligned with the dentry size, the return value of readdir() will be NULL and errno is 0, which means the end of the directory stream is reached. If the position is aligned with dentry size, but there is no file or directory at the position, exfat_readdir() will continue to get dentry from the next dentry. So the dentry gotten by readdir() may not be at the position. After this commit, if the position is not aligned with the dentry size, round the position up to the dentry size and continue to get the dentry. Fixes: ca06197382bd ("exfat: add directory operations") Cc: stable@vger.kernel.org # v5.7+ Reported-by: Wang Yugui Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman --- fs/exfat/dir.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index 56b1bea7d065..3940a56902dd 100644 --- a/fs/exfat/dir.c +++ b/fs/exfat/dir.c @@ -237,10 +237,7 @@ static int exfat_iterate(struct file *filp, struct dir_context *ctx) fake_offset = 1; } - if (cpos & (DENTRY_SIZE - 1)) { - err = -ENOENT; - goto unlock; - } + cpos = round_up(cpos, DENTRY_SIZE); /* name buffer should be allocated before use */ err = exfat_alloc_namebuf(nb);