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Dmitri Monakhov 5b41e74ad1 vfs: fix data leak in nobh_write_end() 
Current nobh_write_end() implementation ignore partial writes(copied < len)
case if page was fully mapped and simply mark page as Uptodate, which is
totally wrong because area [pos+copied, pos+len) wasn't updated explicitly in
previous write_begin call.  It simply contains garbage from pagecache and
result in data leakage.

#TEST_CASE_BEGIN:
~~~~~~~~~~~~~~~~
In fact issue triggered by classical testcase
	open("/mnt/test", O_RDWR|O_CREAT|O_TRUNC, 0666) = 3
	ftruncate(3, 409600)                    = 0
	writev(3, [{"a", 1}, {NULL, 4095}], 2)  = 1
##TESTCASE_SOURCE:
~~~~~~~~~~~~~~~~~
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <sys/mman.h>
#include <errno.h>
int main(int argc, char **argv)
{
	int fd,  ret;
	void* p;
	struct iovec iov[2];
	fd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666);
	ftruncate(fd, 409600);
	iov[0].iov_base="a";
	iov[0].iov_len=1;
	iov[1].iov_base=NULL;
	iov[1].iov_len=4096;
	ret = writev(fd, iov, sizeof(iov)/sizeof(struct iovec));
	printf("writev  = %d, err = %d\n", ret, errno);
	return 0;
}
##TESTCASE RESULT:
~~~~~~~~~~~~~~~~~~
[root@ts63 ~]# mount | grep mnt2
/dev/mapper/test on /mnt2 type ext2 (rw,nobh)
[root@ts63 ~]#  /tmp/writev /mnt2/test
writev  = 1, err = 0
[root@ts63 ~]# hexdump -C /mnt2/test

00000000  61 65 62 6f 6f 74 00 00  f0 b9 b4 59 3a 00 00 00  |aeboot.....Y:...|
00000010  20 00 00 00 00 00 00 00  21 00 00 00 00 00 00 00  | .......!.......|
00000020  df df df df df df df df  df df df df df df df df  |................|
00000030  3a 00 00 00 2a 00 00 00  21 00 00 00 00 00 00 00  |:...*...!.......|
00000040  60 c0 8c 00 00 00 00 00  40 4a 8d 00 00 00 00 00  |`.......@J......|
00000050  00 00 00 00 00 00 00 00  41 00 00 00 00 00 00 00  |........A.......|
00000060  74 69 6d 65 20 64 64 20  69 66 3d 2f 64 65 76 2f  |time dd if=/dev/|
00000070  6c 6f 6f 70 30 20 20 6f  66 3d 2f 64 65 76 2f 6e  |loop0  of=/dev/n|
skip..
00000f50  00 00 00 00 00 00 00 00  31 00 00 00 00 00 00 00  |........1.......|
00000f60  6d 6b 66 73 2e 65 78 74  33 20 2f 64 65 76 2f 76  |mkfs.ext3 /dev/v|
00000f70  7a 76 67 2f 74 65 73 74  20 2d 62 34 30 39 36 00  |zvg/test -b4096.|
00000f80  a0 fe 8c 00 00 00 00 00  21 00 00 00 00 00 00 00  |........!.......|
00000f90  23 31 32 30 35 39 35 30  34 30 34 00 3a 00 00 00  |#1205950404.:...|
00000fa0  20 00 8d 00 00 00 00 00  21 00 00 00 00 00 00 00  | .......!.......|
00000fb0  d0 cf 8c 00 00 00 00 00  10 d0 8c 00 00 00 00 00  |................|
00000fc0  00 00 00 00 00 00 00 00  41 00 00 00 00 00 00 00  |........A.......|
00000fd0  6d 6f 75 6e 74 20 2f 64  65 76 2f 76 7a 76 67 2f  |mount /dev/vzvg/|
00000fe0  74 65 73 74 20 20 2f 76  7a 20 2d 6f 20 64 61 74  |test  /vz -o dat|
00000ff0  61 3d 77 72 69 74 65 62  61 63 6b 00 00 00 00 00  |a=writeback.....|
00001000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

As you can see file's page contains garbage from pagecache instead of zeros.
#TEST_CASE_END

Attached patch:
- Add sanity check BUG_ON in order to prevent incorrect usage by caller,
  This is function invariant because page can has buffers and in no zero
  *fadata pointer at the same time.
- Always attach buffers to page is it is partial write case.
- Always switch back to generic_write_end if page has buffers.
  This is reasonable because if page already has buffer then generic_write_begin
  was called previously.

Signed-off-by: Dmitri Monakhov <dmonakhov@openvz.org>
Reviewed-by: Nick Piggin <npiggin@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-28 14:45:21 -07:00
..
9p Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p) 2008-02-07 08:42:26 -08:00
adfs mount options: fix adfs 2008-02-08 09:22:39 -08:00
affs mount options: fix affs 2008-02-08 09:22:39 -08:00
afs Use path_put() in a few places instead of {mnt,d}put() 2008-02-14 21:13:33 -08:00
autofs mount options: fix autofs 2008-02-08 09:22:40 -08:00
autofs4 Introduce path_put() 2008-02-14 21:13:33 -08:00
befs mount options: fix befs 2008-02-08 09:22:40 -08:00
bfs iget: stop BFS from using iget() and read_inode() 2008-02-07 08:42:27 -08:00
cifs [CIFS] Fix mem leak on dfs referral 2008-03-22 22:57:44 +00:00
coda Introduce path_put() 2008-02-14 21:13:33 -08:00
configfs Introduce path_put() 2008-02-14 21:13:33 -08:00
cramfs
debugfs debugfs: fix sparse warnings 2008-03-04 14:47:06 -08:00
devpts mount options: fix devpts 2008-02-08 09:22:40 -08:00
dlm dlm: fix rcom_names message to self 2008-02-21 15:19:54 -06:00
ecryptfs eCryptfs: Swap dput() and mntput() 2008-03-19 18:53:36 -07:00
efs efs: move headers out of include/linux/ 2008-02-23 17:12:15 -08:00
exportfs
ext2 mount options: fix ext2 2008-02-08 09:22:40 -08:00
ext3 ext3: fix wrong gfp type under transaction 2008-03-19 18:53:36 -07:00
ext4 ext4: add missing ext4_journal_stop() 2008-02-25 15:37:42 -05:00
fat mount options: fix fat 2008-02-08 09:22:40 -08:00
freevxfs iget: stop FreeVXFS from using iget() and read_inode() 2008-02-07 08:42:28 -08:00
fuse fuse: fix permission checking 2008-02-23 17:12:13 -08:00
gfs2 Introduce path_put() 2008-02-14 21:13:33 -08:00
hfs hfs_bnode_find() can fail, resulting in hfs_bnode_split() breakage 2008-03-17 09:46:55 -07:00
hfsplus fs/hfsplus/unicode.c: fix uninitialized var warning 2008-02-08 09:22:36 -08:00
hostfs uml: fix hostfs tv_usec calculations 2008-02-05 09:44:30 -08:00
hpfs mount options: fix hpfs 2008-02-08 09:22:40 -08:00
hppfs [PATCH] sanitize hppfs 2008-03-19 06:42:18 -04:00
hugetlbfs [PATCH] double iput() on failure exit in hugetlb 2008-03-19 06:55:01 -04:00
isofs zisofs: fix readpage() outside i_size 2008-03-19 18:53:36 -07:00
jbd fs: fix kernel-doc notation warnings 2008-03-19 18:53:36 -07:00
jbd2 jbd2: correctly unescape journal data blocks 2008-03-19 18:53:36 -07:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2008-02-07 10:20:31 -08:00
jfs BKL-removal: Implement a compat_ioctl handler for JFS 2008-02-07 13:45:29 -06:00
lockd Wrap buffers used for rpc debug printks into RPC_IFDEBUG 2008-02-21 18:42:29 -05:00
minix iget: stop the MINIX filesystem from using iget() and read_inode() 2008-02-07 08:42:28 -08:00
msdos
ncpfs mount options: fix ncpfs 2008-02-08 09:22:40 -08:00
nfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2008-03-21 07:57:45 -07:00
nfs_common
nfsd nfsd: fix oops on access from high-numbered ports 2008-03-14 16:49:15 -07:00
nls
ntfs is_vmalloc_addr(): Check if an address is within the vmalloc boundaries 2008-02-05 09:44:14 -08:00
ocfs2 ocfs2: Fix NULL pointer dereferences in o2net 2008-03-10 15:14:19 -07:00
openpromfs iget: stop OPENPROMFS from using iget() and read_inode() 2008-02-07 08:42:29 -08:00
partitions Enhanced partition statistics: remove old partition statistics 2008-02-08 12:42:01 +01:00
proc Change pagemap output format to allow for future reporting of huge pages 2008-03-22 17:03:10 -07:00
qnx4 iget: stop QNX4 from using iget() and read_inode() 2008-02-07 08:42:28 -08:00
ramfs
reiserfs [PATCH] reiserfs: eliminate private use of struct file in xattr 2008-03-19 06:49:36 -04:00
romfs ROMFS: Fix up an error in iget removal 2008-03-19 18:53:36 -07:00
smbfs fs/smbfs/inode.c: fix warning message deprecating smbfs 2008-02-13 16:21:19 -08:00
sysfs driver core: debug for bad dev_attr_show() return value. 2008-03-24 22:33:49 -07:00
sysv iget: stop the SYSV filesystem from using iget() and read_inode() 2008-02-07 08:42:29 -08:00
udf udf: fix udf_add_free_space 2008-02-13 16:21:20 -08:00
ufs fs/ufs/balloc.c: fix sparc64 printk warning 2008-03-19 18:53:37 -07:00
vfat Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p) 2008-02-07 08:42:26 -08:00
xfs [XFS] fix inode leak in xfs_iget_core() 2008-03-06 16:38:50 +11:00
aio.c aio: bad AIO race in aio_complete() leads to process hang 2008-03-19 18:53:35 -07:00
anon_inodes.c [PATCH] fix up new filp allocators 2008-03-19 06:54:05 -04:00
attr.c
bad_inode.c iget: introduce a function to register iget failure 2008-02-07 08:42:26 -08:00
binfmt_aout.c aout: suppress A.OUT library support if !CONFIG_ARCH_SUPPORTS_AOUT 2008-02-08 09:22:30 -08:00
binfmt_elf.c core dump: user_regset writeback 2008-03-04 16:35:10 -08:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c FLAT binaries: drop BINFMT_FLAT bad header magic warning 2008-02-14 20:58:05 -08:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c aout: remove unnecessary inclusions of {asm, linux}/a.out.h 2008-02-08 09:22:30 -08:00
bio.c Revert "unexport bio_{,un}map_user" 2008-03-17 21:14:40 +01:00
block_dev.c fs/block_dev.c: remove #if 0'ed code 2008-02-19 10:04:00 +01:00
buffer.c vfs: fix data leak in nobh_write_end() 2008-03-28 14:45:21 -07:00
char_dev.c fs/char_dev.c: chrdev_open marked static and removed from fs.h 2008-02-08 09:22:42 -08:00
compat.c Merge branch 'linus_origin' into hotfixes 2008-02-15 13:36:30 -05:00
compat_binfmt_elf.c x86: compat_binfmt_elf 2008-01-30 13:31:46 +01:00
compat_ioctl.c d_path: Make d_path() use a struct path 2008-02-14 21:17:09 -08:00
dcache.c dentries: Extract common code to remove dentry from lru 2008-02-14 21:17:09 -08:00
dcookies.c d_path: Make d_path() use a struct path 2008-02-14 21:17:09 -08:00
direct-io.c Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user 2008-02-05 09:44:13 -08:00
dnotify.c
dquot.c quota: add possibly missing iput() when quotaon and quotaoff races 2008-03-19 18:53:35 -07:00
drop_caches.c
eventfd.c fs/eventfd.c should #include <linux/syscalls.h> 2008-02-06 10:41:03 -08:00
eventpoll.c lockdep: annotate epoll 2008-02-05 09:44:07 -08:00
exec.c Allow ARG_MAX execve string space even with a small stack limit 2008-03-03 10:12:14 -08:00
fcntl.c fs: remove fastcall, it is always empty 2008-02-08 09:22:31 -08:00
fifo.c
file.c get rid of NR_OPEN and introduce a sysctl_nr_open 2008-02-06 10:41:06 -08:00
file_table.c [PATCH] fix up new filp allocators 2008-03-19 06:54:05 -04:00
filesystems.c
fs-writeback.c fs: fix kernel-doc notation warnings 2008-03-19 18:53:36 -07:00
generic_acl.c
inode.c iget: remove iget() and the read_inode() super op as being obsolete 2008-02-07 08:42:29 -08:00
inotify.c inotify: remove debug code 2008-02-06 10:41:07 -08:00
inotify_user.c Introduce path_put() 2008-02-14 21:13:33 -08:00
internal.h
ioctl.c fix up kerneldoc in fs/ioctl.c a little bit 2008-02-09 11:08:33 -08:00
ioprio.c cfq-iosched: relax IOPRIO_CLASS_IDLE restrictions 2008-01-28 11:38:15 +01:00
Kconfig deprecate smbfs in favour of cifs 2008-02-05 14:37:15 -08:00
Kconfig.binfmt aout: suppress A.OUT library support if !CONFIG_ARCH_SUPPORTS_AOUT 2008-02-08 09:22:30 -08:00
libfs.c Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user 2008-02-05 09:44:13 -08:00
locks.c fs: fix kernel-doc notation warnings 2008-03-19 18:53:36 -07:00
Makefile x86: compat_binfmt_elf Kconfig 2008-01-30 13:31:46 +01:00
mbcache.c
mpage.c docbook: fix filesystems.tmpl source files 2008-03-03 10:47:13 -08:00
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-03-25 08:57:47 -07:00
namespace.c d_path: Make seq_path() use a struct path argument 2008-02-14 21:17:08 -08:00
nfsctl.c Introduce path_put() 2008-02-14 21:13:33 -08:00
no-block.c
open.c [PATCH] check for null vfsmount in dentry_open() 2008-03-19 06:50:44 -04:00
pipe.c [PATCH] fix up new filp allocators 2008-03-19 06:54:05 -04:00
pnode.c MNT_UNBINDABLE fix 2008-02-06 10:41:02 -08:00
pnode.h
posix_acl.c
quota.c Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p) 2008-02-07 08:42:26 -08:00
quota_v1.c
quota_v2.c
read_write.c remove the unused exports of sys_open/sys_read 2008-02-08 09:22:36 -08:00
read_write.h
readdir.c Use mutex_lock_killable in vfs_readdir 2007-12-06 17:39:54 -05:00
select.c make sys_poll() wait at least timeout ms 2008-02-06 10:41:09 -08:00
seq_file.c d_path: Make d_path() use a struct path 2008-02-14 21:17:09 -08:00
signalfd.c fs/signalfd.c should #include <linux/syscalls.h> 2008-02-06 10:41:03 -08:00
splice.c splice: only return -EAGAIN if there's hope of more data 2008-03-04 11:14:39 +01:00
stack.c
stat.c Introduce path_put() 2008-02-14 21:13:33 -08:00
super.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-03-25 08:57:47 -07:00
sync.c
timerfd.c timerfd: new timerfd API 2008-02-05 09:44:07 -08:00
utimes.c Introduce path_put() 2008-02-14 21:13:33 -08:00
xattr.c Introduce path_put() 2008-02-14 21:13:33 -08:00
xattr_acl.c