Memory leak when using schannel ssl_backend #5855
Description
I did this
Build curl with schannel interface as ssl_backend interface on linux.
Test it with valgrind and get something like:
{
<insert_a_suppression_name_here>
Memcheck:Leak
match-leak-kinds: definite
...
fun:_tcsdup
fun:get_cert_location
fun:schannel_connect_step1
fun:schannel_connect_common
fun:Curl_schannel_connect_nonblocking
fun:Curl_ssl_connect_nonblocking
fun:https_connecting
fun:Curl_http_connect
fun:Curl_protocol_connect
fun:multi_runsingle
fun:curl_multi_perform
fun:easy_transfer
fun:easy_perform
fun:curl_easy_perform
fun:operate_do
fun:operate
fun:main
}
I expected the following
No memory leak
curl/libcurl version
master
operating system
uname -a:
Linux test-x64-ub16 4.4.0-97-generic #120-Ubuntu SMP Tue Sep 19 17:28:18 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
explanation
get_cert_location() can return CURLE_SSL_CERTPROBLEM and allocate memory for store_path. In this case, we lost memory in cert_store_path here:
Line 618 in 259a815
Perhaps get_cert_location() is slightly incorrect?
Perhaps change the code something like this (or better)?:
diff --git a/lib/vtls/schannel.c b/lib/vtls/schannel.c
index 1c1432d75..a656c8a55 100644
--- a/lib/vtls/schannel.c
+++ b/lib/vtls/schannel.c
@@ -346,6 +346,8 @@ set_ssl_ciphers(SCHANNEL_CRED *schannel_cred, char *ciphers)
}
#ifdef HAS_CLIENT_CERT_PATH
+
+// Function allocate memory for store_path if CURLE_OK is returned!
static CURLcode
get_cert_location(TCHAR *path, DWORD *store_name, TCHAR **store_path,
TCHAR **thumbprint)
@@ -388,16 +390,16 @@ get_cert_location(TCHAR *path, DWORD *store_name, TCHAR **store_path,
if(sep == NULL)
return CURLE_SSL_CERTPROBLEM;
+ *thumbprint = sep + 1;
+ if(_tcslen(*thumbprint) != CERT_THUMBPRINT_STR_LEN)
+ return CURLE_SSL_CERTPROBLEM;
+
*sep = TEXT('\0');
*store_path = _tcsdup(store_path_start);
*sep = TEXT('\\');
if(*store_path == NULL)
return CURLE_OUT_OF_MEMORY;
- *thumbprint = sep + 1;
- if(_tcslen(*thumbprint) != CERT_THUMBPRINT_STR_LEN)
- return CURLE_SSL_CERTPROBLEM;
-
return CURLE_OK;
}
#endif