coda: Restrict coda messages to the initial user namespace

Remove the slight chance that uids and gids in coda messages will be
interpreted in the wrong user namespace.

- Only allow processes in the initial user namespace to open the coda
  character device to communicate with coda filesystems.
- Explicitly convert the uids in the coda header into the initial user
  namespace.
- In coda_vattr_to_attr make kuids and kgids from the initial user
  namespace uids and gids in struct coda_vattr that just came from
  userspace.
- In coda_iattr_to_vattr convert kuids and kgids into uids and gids
  in the intial user namespace and store them in struct coda_vattr for
  sending to coda userspace programs.

Nothing needs to be changed with mounts as coda does not support
being mounted in anything other than the initial user namespace.

Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/fs/coda/coda_linux.c b/fs/coda/coda_linux.c
index 854ace71268579b9a48e0b0001f1ebfe09c094ea..2849f41e72a209fb689c7b28915566ed8c70cde1 100644 (file)
--- a/fs/coda/coda_linux.c
+++ b/fs/coda/coda_linux.c
@@ -100,9 +100,9 @@ void coda_vattr_to_iattr(struct inode *inode, struct coda_vattr *attr)
        if (attr->va_mode != (u_short) -1)
                inode->i_mode = attr->va_mode | inode_type;
         if (attr->va_uid != -1) 
-               inode->i_uid = (uid_t) attr->va_uid;
+               inode->i_uid = make_kuid(&init_user_ns, (uid_t) attr->va_uid);
         if (attr->va_gid != -1)
-               inode->i_gid = (gid_t) attr->va_gid;
+               inode->i_gid = make_kgid(&init_user_ns, (gid_t) attr->va_gid);
        if (attr->va_nlink != -1)
                set_nlink(inode, attr->va_nlink);
        if (attr->va_size != -1)
@@ -171,10 +171,10 @@ void coda_iattr_to_vattr(struct iattr *iattr, struct coda_vattr *vattr)
                 vattr->va_mode = iattr->ia_mode;
        }
         if ( valid & ATTR_UID ) {
-                vattr->va_uid = (vuid_t) iattr->ia_uid;
+                vattr->va_uid = (vuid_t) from_kuid(&init_user_ns, iattr->ia_uid);
        }
         if ( valid & ATTR_GID ) {
-                vattr->va_gid = (vgid_t) iattr->ia_gid;
+                vattr->va_gid = (vgid_t) from_kgid(&init_user_ns, iattr->ia_gid);
        }
         if ( valid & ATTR_SIZE ) {
                 vattr->va_size = iattr->ia_size;

diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c
index dd60f905d4fe1c88a7fabbb6c32713ca803c2088..ebc2bae6c289038803f4542f88fc8291c5006c8d 100644 (file)
--- a/fs/coda/psdev.c
+++ b/fs/coda/psdev.c
@@ -270,6 +270,9 @@ static int coda_psdev_open(struct inode * inode, struct file * file)
        if (task_active_pid_ns(current) != &init_pid_ns)
                return -EINVAL;
 
+       if (current_user_ns() != &init_user_ns)
+               return -EINVAL;
+
        idx = iminor(inode);
        if (idx < 0 || idx >= MAX_CODADEVS)
                return -ENODEV;

diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c
index 5c6d2cd6ee86361273fa117ed7cbece495c15608..3a731976dc5e999ffb53b10458cb6dc72540fab8 100644 (file)
--- a/fs/coda/upcall.c
+++ b/fs/coda/upcall.c
@@ -52,7 +52,7 @@ static void *alloc_upcall(int opcode, int size)
         inp->ih.opcode = opcode;
        inp->ih.pid = task_pid_nr_ns(current, &init_pid_ns);
        inp->ih.pgid = task_pgrp_nr_ns(current, &init_pid_ns);
-       inp->ih.uid = current_fsuid();
+       inp->ih.uid = from_kuid(&init_user_ns, current_fsuid());
 
        return (void*)inp;
 }
@@ -157,7 +157,7 @@ int venus_lookup(struct super_block *sb, struct CodaFid *fid,
 }
 
 int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
-               vuid_t uid)
+               kuid_t uid)
 {
        union inputArgs *inp;
        union outputArgs *outp;
@@ -166,7 +166,7 @@ int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
        insize = SIZE(release);
        UPARG(CODA_CLOSE);
        
-       inp->ih.uid = uid;
+       inp->ih.uid = from_kuid(&init_user_ns, uid);
         inp->coda_close.VFid = *fid;
         inp->coda_close.flags = flags;
 

diff --git a/include/linux/coda_psdev.h b/include/linux/coda_psdev.h
index 8031d6eef102b71cdf37f2a65202cb4f226f5658..5b8721efa948ec7d93fa7caeb79a535c51e8d69b 100644 (file)
--- a/include/linux/coda_psdev.h
+++ b/include/linux/coda_psdev.h
@@ -34,7 +34,7 @@ int venus_lookup(struct super_block *sb, struct CodaFid *fid,
                 const char *name, int length, int *type, 
                 struct CodaFid *resfid);
 int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
-               vuid_t uid);
+               kuid_t uid);
 int venus_open(struct super_block *sb, struct CodaFid *fid, int flags,
               struct file **f);
 int venus_mkdir(struct super_block *sb, struct CodaFid *dirfid,