password: Fix warning with empty default password ...

When CONFIG_PASSWORD_DEFAULT is unset, the default_passwd buffer is set
to the empty string. The read_default_passwd() function wants to read at
least two characters from that buffer, causing GCC to generate an array
bounds warning:

barebox/common/password.c: In function 'login':
barebox/common/password.c:173:5: warning: array subscript [1, 2147483647] is outside array bounds of 'const char[1]' [-Warray-bounds]
In file included from barebox/common/password.c:30:
include/generated/passwd.h:1:19: note: while referencing 'default_passwd'

Add an ARRAY_SIZE check to default_passwd so that the loop is optimized
away and the warning is no longer generated. Since the
read_default_passwd() function is only called when default_passwd is not
the empty string, this is not a functional change.

Signed-off-by: David Dgien <dgienda125@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: don't export read_default_passwd() ...

This function is used only in common/password.c itself, so it doesn't
need to be exported.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

treewide: remove references to CREDITS ...

The CREDITS file was removed from barebox in 2015 by commit 6570288f2d97
("Remove the CREDITS file"). Remove references to it from several files.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Revert "globalvar: make globalvar functions more consistent" ...

This reverts commit 1b4a05c.

globalvar: make globalvar functions more consistent ...

Similar to the device parameter functions also make the globalvar
functions more consistent. This also adds support for readonly
globalvars and changes several existing globalvars which should
really be readonly to readonly.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

common: password: make use of get_crypto_bytes ...

get_random_bytes is providing prng, if we have HWRNG we should be
able to use it over get_crypto_bytes

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

stdio: rename getc to getchar ...

The function we have implemented as getc has the semantics of the
standard function getchar, so rename it accorgingly.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

include: move run_command prototype to command.h ...

run_command fits much better into command.h, move it there.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login: make some locally used functions static ...

This patch continues cleanup password code from

  commit 40596b8
  Author: Sascha Hauer <s.hauer@pengutronix.de>
  Date:   Thu Aug 27 15:58:50 2015 +0200

      login: cleanup password code

Signed-off-by: Sergey Koshechkin <tritel59@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

passwd: avoid NULL ptr usage ...

Fixes
common/password.c: In function 'check_passwd':
common/password.c:292:4: warning: reading through null pointer (argument 3)
    pr_err("No such digest: %s\n", PASSWD_SUM);

if no algo is enabled in which case PASSWD_SUM is defined to NULL.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login: check return value of digest_alloc ...

digest_alloc can fail, check the return value.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login: cleanup password code ...

- make some locally used functions static
- remove read_passwd which is unused
- some refactoring to make code pathes clearer

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login: rework login mechanism ...

We used to have the login functionality in the /env/bin/init script.
This is hard to review and it's too easy to break the login functionality
with changes to this script. Move the places to ask for a password to
C code where we have only a few places where we have to ask for a password.
Mainly these are run_shell() and the menutree command.

This patch introduces a login() function which will only return if the correct
password has been entered. Following calls will return immediately without
asking for a password again.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: add pbkdf2 support ...

We will use random 32 bytes salt and 10000 round to generate a
32 bytes key.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: add support for sha512 ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

digest: make it multi-instance ...

Now you need to call digest_alloc and when you finish to use it digest_free.

We need this for upcomming aes encryption support and secure boot
as we will need multiple instance of the same digest.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

digest: introduce digest_{init/update/final/length} ...

This will allow to move from a one at a time digest to a multi-instance
with too much impact on the code using it

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

input: Add BB_ prefix to KEY_ defines ...

Our KEY_ defines conflict with the standard Linux KEY_ defines, so
add a BB_ prefix to them.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login/passwd: add default password support ...

even if the env is broken you will have a password

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: fixed underflow on <backspace> ...

due to missing/misplaced boundary check, deleting characters could
underflow the password buffer.

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Treewide: remove address of the Free Software Foundation ...

The FSF address has changed in the past. Instead of updating it
each time the address changes, just drop it completely treewide.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: remove not used variable 'second' ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

login: add timeout support ...

If a timeout is specified and expired the command will be executed
by default boot

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

password: fix command support as module ...

add missing EXPORT_SYMBOL for nan static function

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

add password framework ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>