+ squashfs-squashfs_read_data-need-to-check-if-the-length-is-0.patch added to mm-hotfixes-unstable branch

+ squashfs-squashfs_read_data-need-to-check-if-the-length-is-0.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: squashfs: squashfs_read_data need to check if the length is 0
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     squashfs-squashfs_read_data-need-to-check-if-the-length-is-0.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/squashfs-squashfs_read_data-need-to-check-if-the-length-is-0.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Lizhi Xu <lizhi.xu@windriver.com>
Subject: squashfs: squashfs_read_data need to check if the length is 0
Date: Thu, 16 Nov 2023 11:13:52 +0800

When the length passed in is 0, the pagemap_scan_test_walk() caller should
bail.  This error causes at least a WARN_ON().

Link: https://lkml.kernel.org/r/20231116031352.40853-1-lizhi.xu@windriver.com
Reported-by: syzbot+32d3767580a1ea339a81@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/0000000000000526f2060a30a085@google.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/squashfs/block.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/squashfs/block.c~squashfs-squashfs_read_data-need-to-check-if-the-length-is-0
+++ a/fs/squashfs/block.c
@@ -321,7 +321,7 @@ int squashfs_read_data(struct super_bloc
 		TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
 		      compressed ? "" : "un", length);
 	}
-	if (length < 0 || length > output->length ||
+	if (length <= 0 || length > output->length ||
 			(index + length) > msblk->bytes_used) {
 		res = -EIO;
 		goto out;
_

Patches currently in -mm which might be from lizhi.xu@windriver.com are

squashfs-squashfs_read_data-need-to-check-if-the-length-is-0.patch