[syslinux] [PATCH 6/6] hdt: fix sizeof(char *) misuse

[Gene Cumm]

On Mon, Feb 9, 2015 at 10:01 PM, Jonathan Boeing via Syslinux
<syslinux at zytor.com> wrote:
> The code was passing sizeof(const char *) - not the length of the string
> or the size of the buffer - as the length to strncmp().  These two cases
> don't need the length, so switch to strcmp.

Can we trust that the data will not allow strcmp() to compare more
data than necessary?  In other words, can we trust that there will be
null-terminators?

-- 
-Gene

> Fixes the warning: argument to 'sizeof' in 'strncmp' call is the same
> expression as the second source; did you mean to provide an explicit
> length?
>
> Signed-off-by: Jonathan Boeing <jonathan.n.boeing at gmail.com>
> ---
>  com32/hdt/hdt-cli.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/com32/hdt/hdt-cli.c b/com32/hdt/hdt-cli.c
> index 2895b13..776c8e8 100644
> --- a/com32/hdt/hdt-cli.c
> +++ b/com32/hdt/hdt-cli.c
> @@ -211,7 +211,7 @@ cli_mode_t mode_s_to_mode_t(char *name)
>      int i = 0;
>
>      while (list_modes[i]) {
> -       if (!strncmp(name, list_modes[i]->name, sizeof(list_modes[i]->name)))
> +       if (!strcmp(name, list_modes[i]->name))
>             break;
>         i++;
>      }
> @@ -288,8 +288,7 @@ static void expand_aliases(char *line __unused, char **command, char **module,
>      /* Simple aliases mapping a single command to another one */
>      for (i = 0; i < MAX_ALIASES; i++) {
>         for (j = 0; j < hdt_aliases[i].nb_aliases; j++) {
> -           if (!strncmp(*command, hdt_aliases[i].aliases[j],
> -                        sizeof(hdt_aliases[i].aliases[j]))) {
> +           if (!strcmp(*command, hdt_aliases[i].aliases[j])) {
>                 dprintf("CLI DEBUG: ALIAS %s ", *command);
>                 strlcpy(*command, hdt_aliases[i].command,
>                         sizeof(hdt_aliases[i].command) + 1);
> --
> 2.3.0