--- /dev/null
+From 5b99dea79650b50909c50aba24fbae00f203f013 Mon Sep 17 00:00:00 2001
+From: Phillip Lougher <phillip@squashfs.org.uk>
+Date: Mon, 8 Apr 2024 23:02:06 +0100
+Subject: Squashfs: check the inode number is not the invalid value of zero
+
+From: Phillip Lougher <phillip@squashfs.org.uk>
+
+commit 9253c54e01b6505d348afbc02abaa4d9f8a01395 upstream.
+
+Syskiller has produced an out of bounds access in fill_meta_index().
+
+That out of bounds access is ultimately caused because the inode
+has an inode number with the invalid value of zero, which was not checked.
+
+The reason this causes the out of bounds access is due to following
+sequence of events:
+
+1. Fill_meta_index() is called to allocate (via empty_meta_index())
+ and fill a metadata index. It however suffers a data read error
+ and aborts, invalidating the newly returned empty metadata index.
+ It does this by setting the inode number of the index to zero,
+ which means unused (zero is not a valid inode number).
+
+2. When fill_meta_index() is subsequently called again on another
+ read operation, locate_meta_index() returns the previous index
+ because it matches the inode number of 0. Because this index
+ has been returned it is expected to have been filled, and because
+ it hasn't been, an out of bounds access is performed.
+
+This patch adds a sanity check which checks that the inode number
+is not zero when the inode is created and returns -EINVAL if it is.
+
+[phillip@squashfs.org.uk: whitespace fix]
+ Link: https://lkml.kernel.org/r/20240409204723.446925-1-phillip@squashfs.org.uk
+Link: https://lkml.kernel.org/r/20240408220206.435788-1-phillip@squashfs.org.uk
+Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
+Reported-by: "Ubisectech Sirius" <bugreport@ubisectech.com>
+Closes: https://lore.kernel.org/lkml/87f5c007-b8a5-41ae-8b57-431e924c5915.bugreport@ubisectech.com/
+Cc: Christian Brauner <brauner@kernel.org>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
+Signed-off-by: He Zhe <zhe.he@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/squashfs/inode.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+--- a/fs/squashfs/inode.c
++++ b/fs/squashfs/inode.c
+@@ -48,6 +48,10 @@ static int squashfs_new_inode(struct sup
+ gid_t i_gid;
+ int err;
+
++ inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
++ if (inode->i_ino == 0)
++ return -EINVAL;
++
+ err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
+ if (err)
+ return err;
+@@ -58,7 +62,6 @@ static int squashfs_new_inode(struct sup
+
+ i_uid_write(inode, i_uid);
+ i_gid_write(inode, i_gid);
+- inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
+ inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
+ inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
+ inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;