linux-toradex.git/drivers/md/dm-crypt.c, branch v3.4.2

dm: reject trailing characters in sccanf input

2012-03-28T17:41:26+00:00

Device mapper uses sscanf to convert arguments to numbers. The problem is that
the way we use it ignores additional unmatched characters in the scanned string.

For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number,
but also it will match number with some garbage appended, like "123abc".

As a result, device mapper accepts garbage after some numbers. For example
the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"'
will pass without an error.

This patch fixes all sscanf uses in device mapper. It appends "%c" with
a pointer to a dummy character variable to every sscanf statement.

The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds
only if string is a null-terminated number (optionally preceded by some
whitespace characters). If there is some character appended after the number,
sscanf matches "%c", writes the character to the dummy variable and returns 2.
We check the return value for 1 and consequently reject numbers with some
garbage appended.

Signed-off-by: Mikulas Patocka 
Acked-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm crypt: add missing error handling

2012-03-28T17:41:22+00:00

Always set io->error to -EIO when an error is detected in dm-crypt.

There were cases where an error code would be set only if we finish
processing the last sector. If there were other encryption operations in
flight, the error would be ignored and bio would be returned with
success as if no error happened.

This bug is present in kcryptd_crypt_write_convert, kcryptd_crypt_read_convert
and kcryptd_async_done.

Signed-off-by: Mikulas Patocka 
Cc: stable@kernel.org
Reviewed-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: fix mempool deadlock

2012-03-28T17:41:22+00:00

This patch fixes a possible deadlock in dm-crypt's mempool use.

Currently, dm-crypt reserves a mempool of MIN_BIO_PAGES reserved pages.
It allocates first MIN_BIO_PAGES with non-failing allocation (the allocation
cannot fail and waits until the mempool is refilled). Further pages are
allocated with different gfp flags that allow failing.

Because allocations may be done in parallel, this code can deadlock. Example:
There are two processes, each tries to allocate MIN_BIO_PAGES and the processes
run simultaneously.
It may end up in a situation where each process allocates (MIN_BIO_PAGES / 2)
pages. The mempool is exhausted. Each process waits for more pages to be freed
to the mempool, which never happens.

To avoid this deadlock scenario, this patch changes the code so that only
the first page is allocated with non-failing gfp mask. Allocation of further
pages may fail.

Signed-off-by: Mikulas Patocka 
Cc: stable@kernel.org
Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm: remove the second argument of k[un]map_atomic()

2012-03-20T13:48:28+00:00

Acked-by: Milan Broz 
Signed-off-by: Cong Wang

dm crypt: always disable discard_zeroes_data

2011-09-25T22:26:21+00:00

If optional discard support in dm-crypt is enabled, discards requests
bypass the crypt queue and blocks of the underlying device are discarded.
For the read path, discarded blocks are handled the same as normal
ciphertext blocks, thus decrypted.

So if the underlying device announces discarded regions return zeroes,
dm-crypt must disable this flag because after decryption there is just
random noise instead of zeroes.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: optionally support discard requests

2011-08-02T11:32:08+00:00

Add optional parameter field to dmcrypt table and support
"allow_discards" option.

Discard requests bypass crypt queue processing. Bio is simple remapped
to underlying device.

Note that discard will be never enabled by default because of security
consequences.  It is up to the administrator to enable it for encrypted
devices.

(Note that userspace cryptsetup does not understand new optional
parameters yet.  Support for this will come later.  Until then, you
should use 'dmsetup' to enable and disable this.)

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm table: share target argument parsing functions

2011-08-02T11:32:04+00:00

Move multipath target argument parsing code into dm-table so other
targets can share it.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm: suppress endian warnings

2011-08-02T11:32:01+00:00

Suppress sparse warnings about cpu_to_le32() by using __le32 types for
on-disk data etc.

Signed-off-by: Alasdair G Kergon

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in 
(atomic_inc_not_zero() for now) to 

Signed-off-by: Arun Sharma 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Cc: Eric Dumazet 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

2011-03-26T03:51:44+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm stripe: implement merge method
  dm mpath: allow table load with no priority groups
  dm mpath: fail message ioctl if specified path is not valid
  dm ioctl: add flag to wipe buffers for secure data
  dm ioctl: prepare for crypt key wiping
  dm crypt: wipe keys string immediately after key is set
  dm: add flakey target
  dm: fix opening log and cow devices for read only tables