[U-Boot] [RESEND][PATCH] cmd: nvedit: add whitelist option for env import

[Alex Kiernan]

On Tue, May 15, 2018 at 7:25 PM Joe Hershberger <joe.hershberger at gmail.com>
wrote:

> On Tue, May 15, 2018 at 5:03 AM, Quentin Schulz
> <quentin.schulz at bootlin.com> wrote:
> > While the `env export` can take as parameters variables to be exported,
> > `env import` does not have such a mechanism of variable selection.
> >
> > Let's add a `-w` option that asks `env import` to look for the
> > `whitelisted_vars` env variable for a space-separated list of variables
> > that are whitelisted.
> >
> > Every env variable present in env at `addr` and in `whitelisted_vars`
> > env variable will override the value of the variable in the current env.
> > All the remaining variables are left untouched.
> >
> > One of its use case could be to load a secure environment from the
> > signed U-Boot binary and load only a handful of variables from an
> > other, unsecure, environment without completely losing control of
> > U-Boot.
> >
> > Signed-off-by: Quentin Schulz <quentin.schulz at bootlin.com>
> > ---
> >  cmd/nvedit.c | 66
++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
> >  1 file changed, 62 insertions(+), 4 deletions(-)
> >
> > diff --git a/cmd/nvedit.c b/cmd/nvedit.c
> > index 4e79d03856..4637ec656c 100644
> > --- a/cmd/nvedit.c
> > +++ b/cmd/nvedit.c
> > @@ -971,7 +971,7 @@ sep_err:
> >
> >  #ifdef CONFIG_CMD_IMPORTENV
> >  /*
> > - * env import [-d] [-t [-r] | -b | -c] addr [size]
> > + * env import [-d] [-t [-r] | -b | -c] [-w] addr [size]
> >   *     -d:     delete existing environment before importing;
> >   *             otherwise overwrite / append to existing definitions
> >   *     -t:     assume text format; either "size" must be given or the
> > @@ -982,6 +982,10 @@ sep_err:
> >   *             for line endings. Only effective in addition to -t.
> >   *     -b:     assume binary format ('\0' separated, "\0\0" terminated)
> >   *     -c:     assume checksum protected environment format
> > + *     -w:     specify that whitelisting of variables should be used
when
> > + *             importing environment. The space-separated list of
variables
> > + *             that should override the ones in current environment is
stored
> > + *             in `whitelisted_vars`.
> >   *     addr:   memory address to read from
> >   *     size:   length of input data; if missing, proper '\0'
> >   *             termination is mandatory
> > @@ -991,17 +995,21 @@ static int do_env_import(cmd_tbl_t *cmdtp, int
flag,
> >  {
> >         ulong   addr;
> >         char    *cmd, *ptr;
> > +       char    **array = NULL;
> >         char    sep = '\n';
> >         int     chk = 0;
> >         int     fmt = 0;
> >         int     del = 0;
> >         int     crlf_is_lf = 0;
> > +       int     wl = 0;
> > +       int     wl_count = 0;
> > +       unsigned int i;
> >         size_t  size;
> >
> >         cmd = *argv;
> >
> >         while (--argc > 0 && **++argv == '-') {
> > -               char *arg = *argv;
> > +               char *arg = *argv, *str, *token, *tmp;
> >                 while (*++arg) {
> >                         switch (*arg) {
> >                         case 'b':               /* raw binary format */
> > @@ -1026,6 +1034,43 @@ static int do_env_import(cmd_tbl_t *cmdtp, int
flag,
> >                         case 'd':
> >                                 del = 1;
> >                                 break;
> > +                       case 'w':
> > +                               wl = 1;
> > +                               wl_count = 1;
> > +
> > +                               str = env_get("whitelisted_vars");

> I don't like how this is grabbing the list from the env. I think a
> comma-separated list should be a parameter following the '-w'.


I posted a patch, independently in that vein as I hadn't spotted Quentin's
patch:

http://patchwork.ozlabs.org/patch/891422/

I could clean it up to take parameters in an option.

-- 
Alex Kiernan