Segmentation fault using libcurl to perform an IDLE command in IMAP

[ehlertjd]

I did this

1. Create an IMAP connection using CURLOPT_CONNECT_ONLY.
2. Using curl_easy_send and curl_easy_receive, select the INBOX and perform an IDLE command
3. Send a DONE command and call curl_easy_cleanup
4. Program aborts with a segfault

frame #0: 0x0000000100033d59 libcurl.4.dylib:imap_endofresp + 245'
frame #1: 0x00000001000374c0 libcurl.4.dylib:Curl_pp_readresp + 480
frame #2: 0x0000000100033b06 libcurl.4.dylib:imap_statemach_act + 2045
frame #3: 0x0000000100034758 libcurl.4.dylib:imap_block_statemach + 42
frame #4: 0x00000001000332b7 libcurl.4.dylib:imap_disconnect + 75
frame #5: 0x0000000100019653 libcurl.4.dylib:Curl_disconnect + 103
frame #6: 0x000000010002c55c libcurl.4.dylib:curl_multi_cleanup + 78
frame #7: 0x0000000100014668 libcurl.4.dylib:Curl_close + 60
frame #8: 0x0000000100000d10 test_imap_connect_only:main + 368
frame #9: 0x00007fff90ed15ad libdyld.dylib:start + 1
frame #10: 0x00007fff90ed15ad libdyld.dylib:start + 1

Sample program that crashes here:
imap_idle.cpp

I expected the following

Program should not crash, connection cleanup should occur cleanly.

curl/libcurl version

7.48.0

operating system

OSX 10.11

[captain-caveman2k]

Presumably we have an uninitialised variable as the normal program flow hasn't been followed.

I agree libcurl shouldn't crash but do you know which variable is causing the crash or are you able to debug your program and find out?

[ehlertjd]

Found this at the end of the day yesterday. I plan on digging in a bit more
today.

On Fri, Apr 1, 2016, 3:58 AM Steve Holme notifications@github.com wrote:

Presumably we have an uninitialised variable as the normal program flow
hasn't been followed.

I agree libcurl shouldn't crash but do you know which variable is causing
the crash or are you able to debug your program and find out?

—
You are receiving this because you authored the thread.
Reply to this email directly or view it on GitHub
#747 (comment)

[ehlertjd]

Turns out that the imap pointer on line 372 of imap.c is NULL. Adding a check there resolves the problem. Pull request incoming.

[captain-caveman2k]

Cool - thank you.