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provisioning: use memcpy instead of strncpy for copying SSID

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Per WiFi library requirement, SSID can be non-null terminated string
if its length goes to 32 bytes (maximum). Use of strncpy in this case,
along with compiler optimization level -O2 results in some warnings
for potential use of non-null terminated strings.

Fix here ensures use of memcpy to copy SSID string upto appropriate
desired length. This helps to avoid compiler specific workaround
flags added earlier.

Closes https://github.com/espressif/esp-idf/issues/5866
Closes IDFGH-3983
This commit is contained in:
Mahavir Jain
2020-09-15 12:17:52 +05:30
parent 1a1e1911f9
commit 6a3d50c952
8 changed files with 37 additions and 22 deletions
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11
components/wifi_provisioning/src/handlers.c
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@@ -105,10 +105,15 @@ static esp_err_t set_config_handler(const wifi_prov_config_set_data_t *req_data,
ESP_LOGD(TAG, "Wi-Fi Credentials Received");
/* Using strncpy allows the max SSID length to be 32 bytes (as per 802.11 standard).
/* Using memcpy allows the max SSID length to be 32 bytes (as per 802.11 standard).
* But this doesn't guarantee that the saved SSID will be null terminated, because
* wifi_cfg->sta.ssid is also 32 bytes long (without extra 1 byte for null character) */
strncpy((char *) wifi_cfg->sta.ssid, req_data->ssid, sizeof(wifi_cfg->sta.ssid));
* wifi_cfg->sta.ssid is also 32 bytes long (without extra 1 byte for null character).
* Although, this is not a matter for concern because esp_wifi library reads the SSID
* upto 32 bytes in absence of null termination */
const size_t ssid_len = strnlen(req_data->ssid, sizeof(wifi_cfg->sta.ssid));
/* Ensure SSID less than 32 bytes is null terminated */
memset(wifi_cfg->sta.ssid, 0, sizeof(wifi_cfg->sta.ssid));
memcpy(wifi_cfg->sta.ssid, req_data->ssid, ssid_len);
/* Using strlcpy allows both max passphrase length (63 bytes) and ensures null termination
* because size of wifi_cfg->sta.password is 64 bytes (1 extra byte for null character) */