The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101321-update-disprove-8836@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b Mon Sep 17 00:00:00 2001 From: Phillip Lougher phillip@squashfs.org.uk Date: Fri, 26 Sep 2025 22:59:35 +0100 Subject: [PATCH] Squashfs: reject negative file sizes in squashfs_read_inode()
Syskaller reports a "WARNING in ovl_copy_up_file" in overlayfs.
This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size.
This commit checks for a negative file size and returns EINVAL.
[phillip@squashfs.org.uk: only need to check 64 bit quantity] Link: https://lkml.kernel.org/r/20250926222305.110103-1-phillip@squashfs.org.uk Link: https://lkml.kernel.org/r/20250926215935.107233-1-phillip@squashfs.org.uk Fixes: 6545b246a2c8 ("Squashfs: inode operations") Signed-off-by: Phillip Lougher phillip@squashfs.org.uk Reported-by: syzbot+f754e01116421e9754b9@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68d580e5.a00a0220.303701.0019.GAE@google.com/ Cc: Amir Goldstein amir73il@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c index ddc65d006063..cceae3b78698 100644 --- a/fs/squashfs/inode.c +++ b/fs/squashfs/inode.c @@ -197,6 +197,10 @@ int squashfs_read_inode(struct inode *inode, long long ino) goto failed_read;
inode->i_size = le64_to_cpu(sqsh_ino->file_size); + if (inode->i_size < 0) { + err = -EINVAL; + goto failed_read; + } frag = le32_to_cpu(sqsh_ino->fragment); if (frag != SQUASHFS_INVALID_FRAG) { /*