This is a note to let you know that I've just added the patch titled
nfsd: check permissions when setting ACLs
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-check-permissions-when-setting-acls.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 999653786df6954a31044528ac3f7a5dadca08f4 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Date: Wed, 22 Jun 2016 19:43:35 +0100
Subject: nfsd: check permissions when setting ACLs
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
commit 999653786df6954a31044528ac3f7a5dadca08f4 upstream.
Use set_posix_acl, which includes proper permission checks, instead of
calling ->set_acl directly. Without this anyone may be able to grant
themselves permissions to a file by setting the ACL.
Lock the inode to make the new checks atomic with respect to set_acl.
(Also, nfsd was the only caller of set_acl not locking the inode, so I
suspect this may fix other races.)
This also simplifies the code, and ensures our ACLs are checked by
posix_acl_valid.
The permission checks and the inode locking were lost with commit
4ac7249e, which changed nfsd to use the set_acl inode operation directly
instead of going through xattr handlers.
Reported-by: David Sinquin <david@xxxxxxxxxx>
[agreunba@xxxxxxxxxx: use set_posix_acl]
Fixes: 4ac7249e
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfsd/nfs2acl.c | 20 ++++++++++----------
fs/nfsd/nfs3acl.c | 16 +++++++---------
fs/nfsd/nfs4acl.c | 16 ++++++++--------
3 files changed, 25 insertions(+), 27 deletions(-)
--- a/fs/nfsd/nfs2acl.c
+++ b/fs/nfsd/nfs2acl.c
@@ -104,22 +104,21 @@ static __be32 nfsacld_proc_setacl(struct
goto out;
inode = fh->fh_dentry->d_inode;
- if (!IS_POSIXACL(inode) || !inode->i_op->set_acl) {
- error = -EOPNOTSUPP;
- goto out_errno;
- }
error = fh_want_write(fh);
if (error)
goto out_errno;
- error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);
+ fh_lock(fh);
+
+ error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
if (error)
- goto out_drop_write;
- error = inode->i_op->set_acl(inode, argp->acl_default,
- ACL_TYPE_DEFAULT);
+ goto out_drop_lock;
+ error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
if (error)
- goto out_drop_write;
+ goto out_drop_lock;
+
+ fh_unlock(fh);
fh_drop_write(fh);
@@ -131,7 +130,8 @@ out:
posix_acl_release(argp->acl_access);
posix_acl_release(argp->acl_default);
return nfserr;
-out_drop_write:
+out_drop_lock:
+ fh_unlock(fh);
fh_drop_write(fh);
out_errno:
nfserr = nfserrno(error);
--- a/fs/nfsd/nfs3acl.c
+++ b/fs/nfsd/nfs3acl.c
@@ -95,22 +95,20 @@ static __be32 nfsd3_proc_setacl(struct s
goto out;
inode = fh->fh_dentry->d_inode;
- if (!IS_POSIXACL(inode) || !inode->i_op->set_acl) {
- error = -EOPNOTSUPP;
- goto out_errno;
- }
error = fh_want_write(fh);
if (error)
goto out_errno;
- error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);
+ fh_lock(fh);
+
+ error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
if (error)
- goto out_drop_write;
- error = inode->i_op->set_acl(inode, argp->acl_default,
- ACL_TYPE_DEFAULT);
+ goto out_drop_lock;
+ error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
-out_drop_write:
+out_drop_lock:
+ fh_unlock(fh);
fh_drop_write(fh);
out_errno:
nfserr = nfserrno(error);
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -818,9 +818,6 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqst
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
- if (!inode->i_op->set_acl || !IS_POSIXACL(inode))
- return nfserr_attrnotsupp;
-
if (S_ISDIR(inode->i_mode))
flags = NFS4_ACL_DIR;
@@ -830,16 +827,19 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqst
if (host_error < 0)
goto out_nfserr;
- host_error = inode->i_op->set_acl(inode, pacl, ACL_TYPE_ACCESS);
+ fh_lock(fhp);
+
+ host_error = set_posix_acl(inode, ACL_TYPE_ACCESS, pacl);
if (host_error < 0)
- goto out_release;
+ goto out_drop_lock;
if (S_ISDIR(inode->i_mode)) {
- host_error = inode->i_op->set_acl(inode, dpacl,
- ACL_TYPE_DEFAULT);
+ host_error = set_posix_acl(inode, ACL_TYPE_DEFAULT, dpacl);
}
-out_release:
+out_drop_lock:
+ fh_unlock(fhp);
+
posix_acl_release(pacl);
posix_acl_release(dpacl);
out_nfserr:
Patches currently in stable-queue which might be from ben@xxxxxxxxxxxxxxx are
queue-3.14/nfsd-check-permissions-when-setting-acls.patch
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