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CVE-2016-1237 missing check for permissions setting ACL (rhbz 1350845 1350847)

This commit is contained in:
Josh Boyer 2016-06-28 13:21:53 -04:00
parent 8d3b8964b7
commit f0cec8a3bb
3 changed files with 218 additions and 0 deletions
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9
kernel.spec
View File

@ -656,6 +656,10 @@ Patch826: HID-hiddev-validate-num_values-for-HIDIOCGUSAGES-HID.patch
#CVE-2016-5728 rhbz 1350811 1350812
Patch827: misc-mic-Fix-for-double-fetch-security-bug-in-mic_co.patch
#CVE-2016-1237 rhbz 1350845 1350847
Patch830: posix_acl-Add-set_posix_acl.patch
Patch831: nfsd-check-permissions-when-setting-ACLs.patch
# END OF PATCH DEFINITIONS
%endif
@ -1373,6 +1377,10 @@ ApplyPatch HID-hiddev-validate-num_values-for-HIDIOCGUSAGES-HID.patch
#CVE-2016-5728 rhbz 1350811 1350812
ApplyPatch misc-mic-Fix-for-double-fetch-security-bug-in-mic_co.patch
#CVE-2016-1237 rhbz 1350845 1350847
ApplyPatch posix_acl-Add-set_posix_acl.patch
ApplyPatch nfsd-check-permissions-when-setting-ACLs.patch
# END OF PATCH APPLICATIONS
%endif
@ -2223,6 +2231,7 @@ fi
#
%changelog
* Tue Jun 28 2016 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2016-1237 missing check for permissions setting ACL (rhbz 1350845 1350847)
- CVE-2016-5728 race condition in mic driver (rhbz 1350811 1350812)
* Mon Jun 27 2016 Josh Boyer <jwboyer@fedoraproject.org>

154
nfsd-check-permissions-when-setting-ACLs.patch Normal file
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@ -0,0 +1,154 @@
From 999653786df6954a31044528ac3f7a5dadca08f4 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Wed, 22 Jun 2016 19:43:35 +0100
Subject: [PATCH] nfsd: check permissions when setting ACLs
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@sinquin.eu>
[agreunba@redhat.com: use set_posix_acl]
Fixes: 4ac7249e
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/nfsd/nfs2acl.c | 20 ++++++++++----------
fs/nfsd/nfs3acl.c | 16 +++++++---------
fs/nfsd/nfs4acl.c | 16 ++++++++--------
3 files changed, 25 insertions(+), 27 deletions(-)
diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
index 1580ea6fd64d..d08cd88155c7 100644
--- a/fs/nfsd/nfs2acl.c
+++ b/fs/nfsd/nfs2acl.c
@@ -104,22 +104,21 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst * rqstp,
goto out;
inode = d_inode(fh->fh_dentry);
- 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);
diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c
index 01df4cd7c753..0c890347cde3 100644
--- a/fs/nfsd/nfs3acl.c
+++ b/fs/nfsd/nfs3acl.c
@@ -95,22 +95,20 @@ static __be32 nfsd3_proc_setacl(struct svc_rqst * rqstp,
goto out;
inode = d_inode(fh->fh_dentry);
- 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);
diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index 6adabd6049b7..71292a0d6f09 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -770,9 +770,6 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
dentry = fhp->fh_dentry;
inode = d_inode(dentry);
- if (!inode->i_op->set_acl || !IS_POSIXACL(inode))
- return nfserr_attrnotsupp;
-
if (S_ISDIR(inode->i_mode))
flags = NFS4_ACL_DIR;
@@ -782,16 +779,19 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
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:
--
2.5.5

55
posix_acl-Add-set_posix_acl.patch Normal file
View File

@ -0,0 +1,55 @@
From c463b51e8ea1ae47a7bb8cc2777eb550ad3273e2 Mon Sep 17 00:00:00 2001
From: Andreas Gruenbacher <agruenba@redhat.com>
Date: Wed, 22 Jun 2016 23:57:25 +0200
Subject: [PATCH] posix_acl: Add set_posix_acl
Factor out part of posix_acl_xattr_set into a common function that takes
a posix_acl, which nfsd can also call.
The prototype already exists in include/linux/posix_acl.h.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: stable@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/posix_acl.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 711dd5170376..f30caace5b84 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -786,6 +786,28 @@ posix_acl_xattr_get(const struct xattr_handler *handler,
return error;
}
+int
+set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+ if (!IS_POSIXACL(inode))
+ return -EOPNOTSUPP;
+ if (!inode->i_op->set_acl)
+ return -EOPNOTSUPP;
+
+ if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+ return acl ? -EACCES : 0;
+ if (!inode_owner_or_capable(inode))
+ return -EPERM;
+
+ if (acl) {
+ int ret = posix_acl_valid(acl);
+ if (ret)
+ return ret;
+ }
+ return inode->i_op->set_acl(inode, acl, type);
+}
+EXPORT_SYMBOL(set_posix_acl);
+
static int
posix_acl_xattr_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
--
2.5.5