Re: [PATCH v2] iio: frequency: admv1013: fix NULL pointer dereference on str

Andy Shevchenko
2026-03-03T11:33:48Z

On Tue, Mar 03, 2026 at 11:52:28AM +0200, Antoniu Miclaus wrote:
> When device_property_read_string() fails, str is left uninitialized
> but the code falls through to strcmp(str, ...), dereferencing a garbage
> pointer. Replace manual read/strcmp with
> device_property_match_property_string() which reads the property as a
> single string value and matches it against an array of known valid
> strings, handling the missing property case internally.

...

> +static const char * const admv1013_input_modes[] = { "iq", "if" };

This array has to be indexed.

static const char * const admv1013_input_modes[] = {
[ADMV1013_IQ_MODE] = "iq",
[ADMV1013_IF_MODE] = "if",
};

...

> +static const char * const admv1013_quad_se_modes[] = { "diff", "se-pos", "se-neg" };

Also this one.
Taking into account the indices are not sequential, this may require another
enumerator.

Ideally you need to list all possible modes and choose only supported by
assigning an empty string to unsupported ones.

I haven't checked datasheet to understand why only 6, 9, 12 are in use.
Maybe they can be simply 1, 2, 3 with a formula like 3 + x * 3 ? Dunno.

...

> + switch (ret) {
> + case 1:
> st->quad_se_mode = ADMV1013_SE_MODE_POS;
> - else if (!strcmp(str, "se-neg"))
> + break;
> + case 2:
> st->quad_se_mode = ADMV1013_SE_MODE_NEG;
> + break;

This (the default) should take

case 0:

as well

> + default:
> + st->quad_se_mode = ADMV1013_SE_MODE_DIFF;
> + break;
> + }