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linux-next/fs/coda/coda_linux.c
Eric W. Biederman d83f5901bc 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>
2013-02-13 06:00:53 -08:00

193 lines
5.1 KiB
C

/*
* Inode operations for Coda filesystem
* Original version: (C) 1996 P. Braam and M. Callahan
* Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
*
* Carnegie Mellon encourages users to contribute improvements to
* the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <asm/uaccess.h>
#include <linux/string.h>
#include <linux/coda.h>
#include <linux/coda_psdev.h>
#include "coda_linux.h"
/* initialize the debugging variables */
int coda_fake_statfs;
/* print a fid */
char * coda_f2s(struct CodaFid *f)
{
static char s[60];
sprintf(s, "(%08x.%08x.%08x.%08x)", f->opaque[0], f->opaque[1], f->opaque[2], f->opaque[3]);
return s;
}
/* recognize special .CONTROL name */
int coda_iscontrol(const char *name, size_t length)
{
return ((CODA_CONTROLLEN == length) &&
(strncmp(name, CODA_CONTROL, CODA_CONTROLLEN) == 0));
}
/* recognize /coda inode */
int coda_isroot(struct inode *i)
{
return ( i->i_sb->s_root->d_inode == i );
}
unsigned short coda_flags_to_cflags(unsigned short flags)
{
unsigned short coda_flags = 0;
if ((flags & O_ACCMODE) == O_RDONLY)
coda_flags |= C_O_READ;
if ((flags & O_ACCMODE) == O_RDWR)
coda_flags |= C_O_READ | C_O_WRITE;
if ((flags & O_ACCMODE) == O_WRONLY)
coda_flags |= C_O_WRITE;
if (flags & O_TRUNC)
coda_flags |= C_O_TRUNC;
if (flags & O_CREAT)
coda_flags |= C_O_CREAT;
if (flags & O_EXCL)
coda_flags |= C_O_EXCL;
return coda_flags;
}
/* utility functions below */
void coda_vattr_to_iattr(struct inode *inode, struct coda_vattr *attr)
{
int inode_type;
/* inode's i_flags, i_ino are set by iget
XXX: is this all we need ??
*/
switch (attr->va_type) {
case C_VNON:
inode_type = 0;
break;
case C_VREG:
inode_type = S_IFREG;
break;
case C_VDIR:
inode_type = S_IFDIR;
break;
case C_VLNK:
inode_type = S_IFLNK;
break;
default:
inode_type = 0;
}
inode->i_mode |= inode_type;
if (attr->va_mode != (u_short) -1)
inode->i_mode = attr->va_mode | inode_type;
if (attr->va_uid != -1)
inode->i_uid = make_kuid(&init_user_ns, (uid_t) attr->va_uid);
if (attr->va_gid != -1)
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)
inode->i_size = attr->va_size;
if (attr->va_size != -1)
inode->i_blocks = (attr->va_size + 511) >> 9;
if (attr->va_atime.tv_sec != -1)
inode->i_atime = attr->va_atime;
if (attr->va_mtime.tv_sec != -1)
inode->i_mtime = attr->va_mtime;
if (attr->va_ctime.tv_sec != -1)
inode->i_ctime = attr->va_ctime;
}
/*
* BSD sets attributes that need not be modified to -1.
* Linux uses the valid field to indicate what should be
* looked at. The BSD type field needs to be deduced from linux
* mode.
* So we have to do some translations here.
*/
void coda_iattr_to_vattr(struct iattr *iattr, struct coda_vattr *vattr)
{
unsigned int valid;
/* clean out */
vattr->va_mode = -1;
vattr->va_uid = (vuid_t) -1;
vattr->va_gid = (vgid_t) -1;
vattr->va_size = (off_t) -1;
vattr->va_atime.tv_sec = (time_t) -1;
vattr->va_atime.tv_nsec = (time_t) -1;
vattr->va_mtime.tv_sec = (time_t) -1;
vattr->va_mtime.tv_nsec = (time_t) -1;
vattr->va_ctime.tv_sec = (time_t) -1;
vattr->va_ctime.tv_nsec = (time_t) -1;
vattr->va_type = C_VNON;
vattr->va_fileid = -1;
vattr->va_gen = -1;
vattr->va_bytes = -1;
vattr->va_nlink = -1;
vattr->va_blocksize = -1;
vattr->va_rdev = -1;
vattr->va_flags = 0;
/* determine the type */
#if 0
mode = iattr->ia_mode;
if ( S_ISDIR(mode) ) {
vattr->va_type = C_VDIR;
} else if ( S_ISREG(mode) ) {
vattr->va_type = C_VREG;
} else if ( S_ISLNK(mode) ) {
vattr->va_type = C_VLNK;
} else {
/* don't do others */
vattr->va_type = C_VNON;
}
#endif
/* set those vattrs that need change */
valid = iattr->ia_valid;
if ( valid & ATTR_MODE ) {
vattr->va_mode = iattr->ia_mode;
}
if ( valid & ATTR_UID ) {
vattr->va_uid = (vuid_t) from_kuid(&init_user_ns, iattr->ia_uid);
}
if ( valid & ATTR_GID ) {
vattr->va_gid = (vgid_t) from_kgid(&init_user_ns, iattr->ia_gid);
}
if ( valid & ATTR_SIZE ) {
vattr->va_size = iattr->ia_size;
}
if ( valid & ATTR_ATIME ) {
vattr->va_atime = iattr->ia_atime;
}
if ( valid & ATTR_MTIME ) {
vattr->va_mtime = iattr->ia_mtime;
}
if ( valid & ATTR_CTIME ) {
vattr->va_ctime = iattr->ia_ctime;
}
}