backend-native: Fix stack corruption reading RFCOMM AT+BIA= response

On-stack buffer size is too short for sscanf to read AT+BIA= and AT+BAC=
response strings which have variable length.

Fix this by replacing sscanf with proper copy of input string.

Fixes: cca0d6937 ("bluetooth: add AT+BIA support")
Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/755>
This commit is contained in:
Igor V. Kovalenko 2022-11-24 02:26:02 +03:00
parent e650c2b33e
commit 3c63f8e6dc

View file

@ -617,7 +617,7 @@ static bool hfp_rfcomm_handle(int fd, pa_bluetooth_transport *t, const char *buf
struct transport_data *trd = t->userdata;
pa_bluetooth_backend *b = trd->backend;
int indicator, mode, val;
char str[5];
char *str;
const char *r;
size_t len;
const char *state = NULL;
@ -635,9 +635,10 @@ static bool hfp_rfcomm_handle(int fd, pa_bluetooth_transport *t, const char *buf
c->state = 1;
return true;
} else if (sscanf(buf, "AT+BIA=%s", str) == 1) {
} else if (pa_startswith(buf, "AT+BIA=")) {
/* Indicators start with index 1 and follow the order of the AT+CIND=? response */
str = pa_xstrdup(buf + 7);
for (indicator = 1; (r = pa_split_in_place(str, ",", &len, &state)); indicator++) {
/* Ignore updates to mandatory indicators which are always ON */
if (indicator == CIND_CALL_INDICATOR
@ -656,21 +657,25 @@ static bool hfp_rfcomm_handle(int fd, pa_bluetooth_transport *t, const char *buf
else {
pa_log_error("Unable to parse indicator of AT+BIA command: %s", buf);
rfcomm_write_response(fd, "ERROR");
pa_xfree(str);
return false;
}
}
pa_xfree(str);
return true;
} else if (sscanf(buf, "AT+BAC=%3s", str) == 1) {
} else if (pa_startswith(buf, "AT+BAC=")) {
c->support_msbc = false;
/* check if codec id 2 (mSBC) is in the list of supported codecs */
str = pa_xstrdup(buf + 7);
while ((r = pa_split_in_place(str, ",", &len, &state))) {
if (len == 1 && r[0] == '2') {
c->support_msbc = true;
break;
}
}
pa_xfree(str);
c->support_codec_negotiation = true;