Hi Simon, On Tue, May 15, 2018 at 12:28:14PM -0600, Simon Glass wrote: > Hi Quentin, > > On 15 May 2018 at 20:03, Quentin Schulz <quentin.sch...@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.sch...@bootlin.com> > > --- > > cmd/nvedit.c | 66 > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++---- > > 1 file changed, 62 insertions(+), 4 deletions(-) > > Is this something you could write a sandbox test for? I think it would > be useful. >
I don't know about sandbox tests but I don't see why not.
> >
> > 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");
> > + if (!str) {
> > + puts("## Error: whitelisted_vars is
> > not set.\n");
> > + return CMD_RET_USAGE;
> > + }
> > +
> > + tmp = malloc(sizeof(char) * (strlen(str) +
> > 1));
>
> strdup() ?
>
Thanks for the discovery :)
> Also should check for NULL
>
Indeed.
> > + strcpy(tmp, str);
> > +
> > + token = strchr(tmp, ' ');
> > + while (!token) {
> > + wl_count++;
> > + token = strchr(token + 1, ' ');
> > + }
> > +
> > + strcpy(tmp, str);
> > +
> > + array = malloc(sizeof(char *) * wl_count);
> > + wl_count = 0;
> > +
> > + token = strtok(tmp, " ");
> > + while (token) {
> > + unsigned int size = strlen(token);
> > +
> > + array[wl_count] =
> > malloc(sizeof(char) *
> > + (size +
> > 1));
>
> Check for NULL
>
> > + strcpy(array[wl_count], token);
> > + wl_count++;
> > + token = strtok(NULL, " ");
> > + }
> > +
> > + free(tmp);
> > + break;
> > default:
> > return CMD_RET_USAGE;
> > }
> > @@ -1083,12 +1128,25 @@ static int do_env_import(cmd_tbl_t *cmdtp, int flag,
> > }
> >
> > if (himport_r(&env_htab, ptr, size, sep, del ? 0 : H_NOCLEAR,
> > - crlf_is_lf, 0, NULL) == 0) {
> > + crlf_is_lf, wl ? wl_count : 0, wl ? array : NULL) ==
> > 0) {
> > pr_err("Environment import failed: errno = %d\n", errno);
> > +
> > + if (wl) {
> > + for (i = 0; i < wl_count; i++)
> > + free(array[i]);
> > + free(array);
> > + }
> > +
> > return 1;
> > }
> > gd->flags |= GD_FLG_ENV_READY;
> >
> > + if (wl) {
> > + for (i = 0; i < wl_count; i++)
> > + free(array[i]);
> > + free(array);
> > + }
> > +
>
> Is there a way to avoid repeating that code twice, perhaps goto or
> function call.
>
As told to Joe, I think I could use a goto and keep the appropriate
return value and that'd be cleaner indeed.
Thanks,
Quentin
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