ALSA: core: add isascii() check to card ID generator

The card identifier should contain only safe ASCII characters. The isalnum()
returns true also for characters for non-ASCII characters.

Link: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4135
Link: https://lore.kernel.org/linux-sound/yk3WTvKkwheOon_LzZlJ43PPInz6byYfBzpKkbasww1yzuiMRqn7n6Y8vZcXB-xwFCu_vb8hoNjv7DTNwH5TWjpEuiVsyn9HPCEXqwF4120=@protonmail.com/
Cc: stable@vger.kernel.org
Reported-by: Barnabás Pőcze <pobrn@protonmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://patch.msgid.link/20241002194649.1944696-1-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/init.c b/sound/core/init.c
index b92aa71..114fb87 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -654,13 +654,19 @@ void snd_card_free(struct snd_card *card)
 }
 EXPORT_SYMBOL(snd_card_free);
 
+/* check, if the character is in the valid ASCII range */
+static inline bool safe_ascii_char(char c)
+{
+       return isascii(c) && isalnum(c);
+}
+
 /* retrieve the last word of shortname or longname */
 static const char *retrieve_id_from_card_name(const char *name)
 {
        const char *spos = name;
 
        while (*name) {
-               if (isspace(*name) && isalnum(name[1]))
+               if (isspace(*name) && safe_ascii_char(name[1]))
                        spos = name + 1;
                name++;
        }
@@ -687,12 +693,12 @@ static void copy_valid_id_string(struct snd_card *card, const char *src,
 {
        char *id = card->id;
 
-       while (*nid && !isalnum(*nid))
+       while (*nid && !safe_ascii_char(*nid))
                nid++;
        if (isdigit(*nid))
                *id++ = isalpha(*src) ? *src : 'D';
        while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
-               if (isalnum(*nid))
+               if (safe_ascii_char(*nid))
                        *id++ = *nid;
                nid++;
        }
@@ -787,7 +793,7 @@ static ssize_t id_store(struct device *dev, struct device_attribute *attr,
 
        for (idx = 0; idx < copy; idx++) {
                c = buf[idx];
-               if (!isalnum(c) && c != '_' && c != '-')
+               if (!safe_ascii_char(c) && c != '_' && c != '-')
                        return -EINVAL;
        }
        memcpy(buf1, buf, copy);