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From: Mark Salyzyn <salyzyn@android.com>
To: linux-kernel@vger.kernel.org
Cc: kernel-team@android.com, Mark Salyzyn <salyzyn@android.com>,
	John Stultz <john.stultz@linaro.org>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	linux-security-module@vger.kernel.org
Subject: [PATCH v17 4/4] overlayfs: inode_owner_or_capable called during execv
Date: Tue, 20 Oct 2020 12:17:32 -0700	[thread overview]
Message-ID: <20201020191732.4049987-5-salyzyn@android.com> (raw)
In-Reply-To: <20201020191732.4049987-1-salyzyn@android.com>

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@linaro.org>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Fixes: 05acefb4872da ("ovl: check permission to open real file")
To: linux-fsdevel@vger.kernel.org
To: linux-unionfs@vger.kernel.org
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: linux-kernel@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: kernel-team@android.com

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


  parent reply	other threads:[~2020-10-20 19:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 19:17 [PATCH v17 0/4] overlayfs override_creds=off & nested get xattr fix Mark Salyzyn
2020-10-20 19:17 ` [PATCH v17 1/4] Add flags option to get xattr method paired to __vfs_getxattr Mark Salyzyn
2020-10-21  1:17   ` Paul Moore
2020-10-21 12:07     ` Mark Salyzyn
2020-10-23  0:46       ` Paul Moore
2020-10-20 19:17 ` [PATCH v17 2/4] overlayfs: handle XATTR_NOSECURITY flag for get xattr method Mark Salyzyn
2020-10-20 22:38   ` kernel test robot
2020-10-21 12:12   ` Mark Salyzyn
2020-10-20 19:17 ` [PATCH v17 3/4] overlayfs: override_creds=off option bypass creator_cred Mark Salyzyn
2020-10-20 19:17 ` Mark Salyzyn [this message]
2020-10-20 23:10 ` [PATCH v17 0/4] overlayfs override_creds=off & nested get xattr fix Paul Moore

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