Re: [PATCH 1/4] param: Move function next_arg to lib/cmdline.c for later reuse

[Kees Cook]

On Mon, Apr 17, 2017 at 6:34 AM, Baoquan He <bhe@xxxxxxxxxx> wrote:
> next_arg will be used to parse cmdline in x86/boot/compressed code,
> so move it to lib/cmdline.c for better code reuse.
>
> No change in functionality.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Jessica Yu <jeyu@xxxxxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> Cc: zijun_hu <zijun_hu@xxxxxxx>
> Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
> Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> Cc: "Niklas SÃderlund" <niklas.soderlund+renesas@xxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  include/linux/kernel.h |  1 +
>  kernel/params.c        | 52 ---------------------------------------------
>  lib/cmdline.c          | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 58 insertions(+), 52 deletions(-)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 4c26dc3..7ae2567 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -438,6 +438,7 @@ extern int get_option(char **str, int *pint);
>  extern char *get_options(const char *str, int nints, int *ints);
>  extern unsigned long long memparse(const char *ptr, char **retptr);
>  extern bool parse_option_str(const char *str, const char *option);
> +extern char *next_arg(char *args, char **param, char **val);
>
>  extern int core_kernel_text(unsigned long addr);
>  extern int core_kernel_data(unsigned long addr);
> diff --git a/kernel/params.c b/kernel/params.c
> index a6d6149..60b2d81 100644
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -160,58 +160,6 @@ static int parse_one(char *param,
>         return -ENOENT;
>  }
>
> -/* You can use " around spaces, but can't escape ". */
> -/* Hyphens and underscores equivalent in parameter names. */
> -static char *next_arg(char *args, char **param, char **val)
> -{
> -       unsigned int i, equals = 0;
> -       int in_quote = 0, quoted = 0;
> -       char *next;
> -
> -       if (*args == '"') {
> -               args++;
> -               in_quote = 1;
> -               quoted = 1;
> -       }
> -
> -       for (i = 0; args[i]; i++) {
> -               if (isspace(args[i]) && !in_quote)
> -                       break;
> -               if (equals == 0) {
> -                       if (args[i] == '=')
> -                               equals = i;
> -               }
> -               if (args[i] == '"')
> -                       in_quote = !in_quote;
> -       }
> -
> -       *param = args;
> -       if (!equals)
> -               *val = NULL;
> -       else {
> -               args[equals] = '\0';
> -               *val = args + equals + 1;
> -
> -               /* Don't include quotes in value. */
> -               if (**val == '"') {
> -                       (*val)++;
> -                       if (args[i-1] == '"')
> -                               args[i-1] = '\0';
> -               }
> -       }
> -       if (quoted && args[i-1] == '"')
> -               args[i-1] = '\0';
> -
> -       if (args[i]) {
> -               args[i] = '\0';
> -               next = args + i + 1;
> -       } else
> -               next = args + i;
> -
> -       /* Chew up trailing spaces. */
> -       return skip_spaces(next);
> -}
> -
>  /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
>  char *parse_args(const char *doing,
>                  char *args,
> diff --git a/lib/cmdline.c b/lib/cmdline.c
> index 8f13cf7..6e3abfb 100644
> --- a/lib/cmdline.c
> +++ b/lib/cmdline.c
> @@ -15,6 +15,7 @@
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/string.h>
> +#include <linux/ctype.h>
>
>  /*
>   *     If a hyphen was found in get_option, this will handle the
> @@ -189,3 +190,59 @@ bool parse_option_str(const char *str, const char *option)
>
>         return false;
>  }
> +
> +/*
> + * Parse a string to get a param value pair.
> + * You can use " around spaces, but can't escape ".
> + * Hyphens and underscores equivalent in parameter names.
> + */
> +char *next_arg(char *args, char **param, char **val)
> +{
> +       unsigned int i, equals = 0;
> +       int in_quote = 0, quoted = 0;
> +       char *next;
> +
> +       if (*args == '"') {
> +               args++;
> +               in_quote = 1;
> +               quoted = 1;
> +       }
> +
> +       for (i = 0; args[i]; i++) {
> +               if (isspace(args[i]) && !in_quote)
> +                       break;
> +               if (equals == 0) {
> +                       if (args[i] == '=')
> +                               equals = i;
> +               }
> +               if (args[i] == '"')
> +                       in_quote = !in_quote;
> +       }
> +
> +       *param = args;
> +       if (!equals)
> +               *val = NULL;
> +       else {
> +               args[equals] = '\0';
> +               *val = args + equals + 1;
> +
> +               /* Don't include quotes in value. */
> +               if (**val == '"') {
> +                       (*val)++;
> +                       if (args[i-1] == '"')
> +                               args[i-1] = '\0';
> +               }
> +       }
> +       if (quoted && args[i-1] == '"')
> +               args[i-1] = '\0';
> +
> +       if (args[i]) {
> +               args[i] = '\0';
> +               next = args + i + 1;
> +       } else
> +               next = args + i;
> +
> +       /* Chew up trailing spaces. */
> +       return skip_spaces(next);
> +       //return next;
> +}
> --
> 2.5.5
>



-- 
Kees Cook
Pixel Security