esp_http_client exception on 401 without Www-Authenticate header

[kluverp]

Environment

• Development Kit: [none]
• Kit version (for WroverKit/PicoKit/DevKitC): -
• Core (if using chip or module): [ESP-WROOM3]
• IDF version: be81d2c
• Development Env: [Eclipse]
• Operating System: [Ubuntu 16.04]
• Power Supply: [external 3.3V]

Problem Description

When the server gives back a 401 response and the "Www-Authenticate" header is missing, a null pointer Exception occurs in the function "http_utils_trim_whitespace()".

On line 70 in "/components/esp_http_client/lib/http_utils.c" a NULL pointer may be passed in, when header is missing:

...
char *end;
    char *start = *str;

    // Trim leading space
    while (isspace((unsigned char)*start)) start ++;
...

Expected Behavior

Maybe issue warning?

Debug Logs

I (12025) HTTP_CLIENT: Posting to https://192.168.1.130/
Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.
Core 1 register dump:
PC : 0x4010d4dc PS : 0x00060930 A0 : 0x8010c01f A1 : 0x3ffcabe0
0x4010d4dc: http_utils_trim_whitespace at /home/peter/esp/esp-idf-master/components/esp_http_client/lib/http_utils.c:74 (discriminator 1)

A2 : 0x3ffcac00 A3 : 0x00000000 A4 : 0x3ff96354 A5 : 0x0000ca11
A6 : 0x00000191 A7 : 0x00000000 A8 : 0x00000000 A9 : 0x00000000
A10 : 0x00000000 A11 : 0x3ffd4b04 A12 : 0x00000010 A13 : 0x00000000
A14 : 0x3ffcb230 A15 : 0xff000000 SAR : 0x00000010 EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000000 LBEG : 0x4000c2e0 LEND : 0x4000c2f6 LCOUNT : 0x00000000

Backtrace: 0x4010d4dc:0x3ffcabe0 0x4010c01c:0x3ffcac00 0x4010c392:0x3ffcac30 0x400d6aef:0x3ffcac50 0x400d6b87:0x3ffcace0
0x4010d4dc: http_utils_trim_whitespace at /home/peter/esp/esp-idf-master/components/esp_http_client/lib/http_utils.c:74 (discriminator 1)

0x4010c01c: esp_http_check_response at /home/peter/esp/esp-idf-master/components/esp_http_client/esp_http_client.c:981

0x4010c392: esp_http_client_perform at /home/peter/esp/esp-idf-master/components/esp_http_client/esp_http_client.c:981

0x400d6aef: http_rest() at /home/peter/esp/WTW_controller/main/API/http_client.cpp:109

0x400d6b87: http_test_task(void*) at /home/peter/esp/WTW_controller/main/API/http_client.cpp:498 (discriminator 8)

[tuanpmt]

Thanks for discovering this issue, the fix is pending internal review and will be updated shortly