linux-kernel - [RESEND PATCH v18 4/4] overlayfs: inode_owner_or

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20201022131652.2784152-1-salyzyn@android.com>
Date:   Thu, 22 Oct 2020 06:16:52 -0700
From:   Mark Salyzyn <salyzyn@...roid.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...roid.com, John Stultz <john.stultz@...aro.org>,
        Mark Salyzyn <salyzyn@...roid.com>,
        linux-fsdevel@...r.kernel.org, linux-unionfs@...r.kernel.org,
        Stephen Smalley <sds@...ho.nsa.gov>,
        linux-security-module@...r.kernel.org, selinux@...r.kernel.org
Subject: [RESEND PATCH v18 4/4] overlayfs: inode_owner_or_capable called during execv

From: John Stultz <john.stultz@...aro.org>

Using old_creds as an indication that we are not overriding the
credentials, bypass call to inode_owner_or_capable.  This solves
a problem with all execv calls being blocked when using the caller's
credentials.

Signed-off-by: John Stultz <john.stultz@...aro.org>
Signed-off-by: Mark Salyzyn <salyzyn@...roid.com>
Fixes: 05acefb4872da ("ovl: check permission to open real file")
Cc: linux-fsdevel@...r.kernel.org
Cc: linux-unionfs@...r.kernel.org
Cc: Stephen Smalley <sds@...ho.nsa.gov>
Cc: linux-kernel@...r.kernel.org
Cc: linux-security-module@...r.kernel.org
Cc: kernel-team@...roid.com
Cc: selinux@...r.kernel.org

v18 - rebase

v17 - rebase

v16 - introduced fix over rebased series
---
 fs/overlayfs/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index b1357bb067d9..9ab9663b02d8 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -53,7 +53,7 @@ static struct file *ovl_open_realfile(const struct file *file,
 	err = inode_permission(realinode, MAY_OPEN | acc_mode);
 	if (err) {
 		realfile = ERR_PTR(err);
-	} else if (!inode_owner_or_capable(realinode)) {
+	} else if (old_cred && !inode_owner_or_capable(realinode)) {
 		realfile = ERR_PTR(-EPERM);
 	} else {
 		realfile = open_with_fake_path(&file->f_path, flags, realinode,
-- 
2.29.0.rc1.297.gfa9743e501-goog