qemu/hw/9pfs/virtio-9p-xattr-user.c
Chen Gang 4fa4ce7107 hw/9pfs: use g_strdup_printf() instead of PATH_MAX limitation
When path is truncated by PATH_MAX limitation, it causes QEMU to access
incorrect file. So use original full path instead of PATH_MAX within
9pfs (need check/process ENOMEM for related memory allocation).

The related test:

 - Environments (for qemu-devel):

   - Host is under fedora17 desktop with ext4fs:

     qemu-system-x86_64 -hda test.img -m 1024 \
       -net nic,vlan=4,model=virtio,macaddr=00:16:35:AF:94:04 \
       -net tap,vlan=4,ifname=tap4,script=no,downscript=no \
       -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=hostshare \
       -fsdev local,security_model=passthrough,id=fsdev0,\
         path=/upstream/vm/data/share/1234567890abcdefghijklmnopqrstuvwxyz\
           ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890acdefghijklmnopqrstuvwxyz\
           ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890/111111111111111111111111111\
           1111111111111111111111111111111111111111111111111111222222222222\
           2222222222222222222222222222222222222222222222222222222222222222\
           2222222222222222222222222222222222233333333333333333333333333333\
           3333333333333333333333333333333333

    - Guest is ubuntu12 server with 9pfs.

      mount -t 9p -o trans=virtio,version=9p2000.L hostshare /share

    - Limitations:

      full path limitation is PATH_MAX (4096B include nul) under Linux.
      file/dir node name maximized length is 256 (include nul) under ext4.

 - Special test:

    Under host, modify the file: "/upstream/vm/data/share/1234567890abcdefg\
      hijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890acdefghijklmno\
      pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890/111111111111111111111\
      111111111111111111111111111111111111111111111111111111111122222222222\
      222222222222222222222222222222222222222222222222222222222222222222222\
      222222222222222222222222222222233333333333333333333333333333333333333\
      3333333333333333333333333/4444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444/55555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      55555555/666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666/77777777777777777777777777777777777777777777777\
      777777777777777777777777777777777777777777777777777777777777777777777\
      777777777777777777777777777777777777777777777777777777777777777777777\
      77777777777777777777777777777777777777777777777777777777777/888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888/99999999999999999999999999999999999999999999999999999999999\
      999999999999999999999999999999999999999999999999999999999999999999999\
      999999999999999999999999999999999999999999999999999999999999999999999\
      99999999999999999999999999999999999999999/000000000000000000000000000\
      000000000000000000000000000000000000000000000000000000000000000000000\
      000000000000000000000000000000000000000000000000000000000000000000000\
      000000000000000000000000000000000000000000000000/aaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/ccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      cccccccccc/dddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      dddddddddddddddddddddd/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee/fffffffffffffff\
      fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff\
      fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff\
      ffffffffffffffffffffffffffffffffffffffffffffffffffffffffff/gggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggg/iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii/jjjjjjjjjjjjj\
      jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj\
      jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj/ppppppppppppppppppppp\
      ppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp\
      ppppppppppppppppppppppppppppppppppppppp/test1234567890file.log"
        (need enter dir firstly, then modify file, or can not open it).

   Under guest, still allow modify "test1234567890file.log" (will generate
   "test123456" file with contents).

   After apply this patch, can not open "test1234567890file.log" under guest
   (permission denied).

 - Common test:

   All are still OK after apply this path.

     "mkdir -p", "create/open file/dir", "modify file/dir", "rm file/dir".
     change various mount point paths under host and/or guest.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2014-03-04 00:57:57 +05:30

129 lines
3.1 KiB
C

/*
* Virtio 9p user. xattr callback
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include <sys/types.h>
#include "hw/virtio/virtio.h"
#include "virtio-9p.h"
#include "fsdev/file-op-9p.h"
#include "virtio-9p-xattr.h"
static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
const char *name, void *value, size_t size)
{
char *buffer;
ssize_t ret;
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = ENOATTR;
return -1;
}
buffer = rpath(ctx, path);
ret = lgetxattr(buffer, name, value, size);
g_free(buffer);
return ret;
}
static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
char *name, void *value, size_t size)
{
int name_size = strlen(name) + 1;
if (strncmp(name, "user.virtfs.", 12) == 0) {
/* check if it is a mapped posix acl */
if (strncmp(name, "user.virtfs.system.posix_acl_", 29) == 0) {
/* adjust the name and size */
name += 12;
name_size -= 12;
} else {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
return 0;
}
}
if (!value) {
return name_size;
}
if (size < name_size) {
errno = ERANGE;
return -1;
}
/* name_size includes the trailing NUL. */
memcpy(value, name, name_size);
return name_size;
}
static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
void *value, size_t size, int flags)
{
char *buffer;
int ret;
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
buffer = rpath(ctx, path);
ret = lsetxattr(buffer, name, value, size, flags);
g_free(buffer);
return ret;
}
static int mp_user_removexattr(FsContext *ctx,
const char *path, const char *name)
{
char *buffer;
int ret;
if (strncmp(name, "user.virtfs.", 12) == 0) {
/*
* Don't allow fetch of user.virtfs namesapce
* in case of mapped security
*/
errno = EACCES;
return -1;
}
buffer = rpath(ctx, path);
ret = lremovexattr(buffer, name);
g_free(buffer);
return ret;
}
XattrOperations mapped_user_xattr = {
.name = "user.",
.getxattr = mp_user_getxattr,
.setxattr = mp_user_setxattr,
.listxattr = mp_user_listxattr,
.removexattr = mp_user_removexattr,
};
XattrOperations passthrough_user_xattr = {
.name = "user.",
.getxattr = pt_getxattr,
.setxattr = pt_setxattr,
.listxattr = pt_listxattr,
.removexattr = pt_removexattr,
};