From: Yuezhang Mo Date: Thu, 12 Dec 2024 08:29:23 +0000 (+0800) Subject: exfat: fix the new buffer was not zeroed before writing X-Git-Url: https://repo.jachan.dev/J-linux.git/commitdiff_plain/98e2fb26d1a9eafe79f46d15d54e68e014d81d8c exfat: fix the new buffer was not zeroed before writing Before writing, if a buffer_head marked as new, its data must be zeroed, otherwise uninitialized data in the page cache will be written. So this commit uses folio_zero_new_buffers() to zero the new buffers before ->write_end(). Fixes: 6630ea49103c ("exfat: move extend valid_size into ->page_mkwrite()") Reported-by: syzbot+91ae49e1c1a2634d20c0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=91ae49e1c1a2634d20c0 Tested-by: syzbot+91ae49e1c1a2634d20c0@syzkaller.appspotmail.com Signed-off-by: Yuezhang Mo Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon --- diff --git a/fs/exfat/file.c b/fs/exfat/file.c index fb38769c3e39..05b51e721783 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -545,6 +545,7 @@ static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size) while (pos < new_valid_size) { u32 len; struct folio *folio; + unsigned long off; len = PAGE_SIZE - (pos & (PAGE_SIZE - 1)); if (pos + len > new_valid_size) @@ -554,6 +555,9 @@ static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size) if (err) goto out; + off = offset_in_folio(folio, pos); + folio_zero_new_buffers(folio, off, off + len); + err = ops->write_end(file, mapping, pos, len, len, folio, NULL); if (err < 0) goto out; @@ -563,6 +567,8 @@ static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size) cond_resched(); } + return 0; + out: return err; }