From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 95079250BE9; Wed, 5 Mar 2025 17:56:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197384; cv=none; b=FNUPDpdFaiBNlnYjY9ykSICeb3FG49xaIfF+D+m5xUNmnFAOeXR0WnOoobY/+rKdwrtLfsxx1euCMHgBx4ui1qFnpFbTuhy1C7NPTEhhtO0RN0XwlVV3bMCaImHRYT5htTGIjZhbiPd4vYAXKaxSknUT/q+g9IW4wLUaB6PqFVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197384; c=relaxed/simple; bh=cBcgtfEB/4giwI4PiZvnysKoBxtGEEvADolXR+s1Ye8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lOQWcYccHTizTJVK8tfNmKX0a8VEb9c+1ajI3W9n0jl+oHikukxa5N/YjNUUeSE31nQcLpi4va8R5pkZWhKVaUFJ8fKmY4C/P+sWfRF47q8A7CeR9s/aYqytmifY0NyISFUbCyT/zjON7BczhbBKGazvCDqHXi1N/zG9ifzkj4Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CxcdCGl9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CxcdCGl9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A2D9C4CED1; Wed, 5 Mar 2025 17:56:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197384; bh=cBcgtfEB/4giwI4PiZvnysKoBxtGEEvADolXR+s1Ye8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CxcdCGl9VaRkWpvCQSu4ySZ2NACozj5qhsHvP8Pr4+hagUWIsJGrCSidwE8lyYNUc X3YAI31ncpvO6xV6vVq4vlePgAoIVtTJvpjUkHq+HMAKq7HKr7+fa9OEATRFFt0o+f Sxw2QkMaRvn4ooTUjDESXt+Oqmb1vDUy9i9QiBXc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+316db8a1191938280eb6@syzkaller.appspotmail.com, Vasiliy Kovalev , Amir Goldstein , Christian Brauner , Sasha Levin Subject: [PATCH 6.1 106/176] ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up Date: Wed, 5 Mar 2025 18:47:55 +0100 Message-ID: <20250305174509.721412710@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174505.437358097@linuxfoundation.org> References: <20250305174505.437358097@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vasiliy Kovalev [ Upstream commit c84e125fff2615b4d9c259e762596134eddd2f27 ] The issue was caused by dput(upper) being called before ovl_dentry_update_reval(), while upper->d_flags was still accessed in ovl_dentry_remote(). Move dput(upper) after its last use to prevent use-after-free. BUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline] BUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 ovl_dentry_remote fs/overlayfs/util.c:162 [inline] ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 ovl_link_up fs/overlayfs/copy_up.c:610 [inline] ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223 ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136 vfs_rename+0xf84/0x20a0 fs/namei.c:4893 ... Fixes: b07d5cc93e1b ("ovl: update of dentry revalidate flags after copy up") Reported-by: syzbot+316db8a1191938280eb6@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=316db8a1191938280eb6 Signed-off-by: Vasiliy Kovalev Link: https://lore.kernel.org/r/20250214215148.761147-1-kovalev@altlinux.org Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/overlayfs/copy_up.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 86d4b6975dbcb..203b88293f6bb 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -532,7 +532,6 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) err = PTR_ERR(upper); if (!IS_ERR(upper)) { err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper); - dput(upper); if (!err) { /* Restore timestamps on parent (best effort) */ @@ -540,6 +539,7 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) ovl_dentry_set_upper_alias(c->dentry); ovl_dentry_update_reval(c->dentry, upper); } + dput(upper); } inode_unlock(udir); if (err) -- 2.39.5