Module: monitoring-plugins
Branch: master
Commit: db2983da7e8175ca3928998d4547acdf75d55dc0
Author: Lorenz Kästle <[email protected]>
Committer: GitHub <[email protected]>
Date: Fri Nov 28 12:21:08 2025 +0100
URL:
https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=db2983da
Fix/check curl sticky redir (#2188)
* check_curl: avoid freeing memory when we don't know where it came from
* check_curl: when using -f sticky conserve IPv6 addresses properly
When running the check on an ipv6 address with a sticky onredirect
policy like in this example:
check_curl -6 -H example.com -I ::1 -f sticky
It results in a getaddrinfo error:
HTTP CRITICAL - Unable to lookup IP address for '[::1]': getaddrinfo returned
-3 - Temporary failure in name resolution
This happens because in check_http() if the content of server_addr is an
ipv6 address enclosing brackets are added and on redirection a
subsequent call to check_http() will pass this now bracketed value to
getaddrinfo resulting in the error.
To work around this, strip the brackets from the address prior to the
lookup_host() call.
* add Michael Jeanson to thanks
---
THANKS.in | 1 +
plugins/check_curl.c | 10 +++-------
plugins/check_curl.d/check_curl_helpers.c | 14 +++++++++++++-
plugins/check_curl.d/check_curl_helpers.h | 4 ++++
4 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/THANKS.in b/THANKS.in
index 66397ad1..5dbb1b39 100644
--- a/THANKS.in
+++ b/THANKS.in
@@ -426,3 +426,4 @@ Eunice Remoquillo
Louis Sautier
Sven Hartge
Alvar Penning
+Michael Jeanson
diff --git a/plugins/check_curl.c b/plugins/check_curl.c
index ba856a11..e3e514ff 100644
--- a/plugins/check_curl.c
+++ b/plugins/check_curl.c
@@ -68,10 +68,6 @@ const char *email = "[email protected]";
#include <netdb.h>
-enum {
- MAX_IPV4_HOSTLENGTH = 255,
-};
-
enum {
REGS = 2,
};
@@ -789,21 +785,21 @@ redir_wrapper redir(curlhelp_write_curlbuf *header_buf,
const check_curl_config
/* set new values for redirected request */
if (!(config.followsticky & STICKY_HOST)) {
- free(working_state.server_address);
+ // free(working_state.server_address);
working_state.server_address = strndup(new_host,
MAX_IPV4_HOSTLENGTH);
}
if (!(config.followsticky & STICKY_PORT)) {
working_state.serverPort = (unsigned short)new_port;
}
- free(working_state.host_name);
+ // free(working_state.host_name);
working_state.host_name = strndup(new_host, MAX_IPV4_HOSTLENGTH);
/* reset virtual port */
working_state.virtualPort = working_state.serverPort;
free(new_host);
- free(working_state.server_url);
+ // free(working_state.server_url);
working_state.server_url = new_url;
uriFreeUriMembersA(&uri);
diff --git a/plugins/check_curl.d/check_curl_helpers.c
b/plugins/check_curl.d/check_curl_helpers.c
index d49d8f07..e4e7bef6 100644
--- a/plugins/check_curl.d/check_curl_helpers.c
+++ b/plugins/check_curl.d/check_curl_helpers.c
@@ -128,8 +128,20 @@ check_curl_configure_curl(const
check_curl_static_curl_config config,
char dnscache[DEFAULT_BUFFER_SIZE];
char addrstr[DEFAULT_BUFFER_SIZE / 2];
if (working_state.use_ssl && working_state.host_name != NULL) {
+ char *tmp_mod_address;
+
+ /* lookup_host() requires an IPv6 address without the brackets.
*/
+ if ((strnlen(working_state.server_address, MAX_IPV4_HOSTLENGTH)
> 2) &&
+ (working_state.server_address[0] == '[')) {
+ // Duplicate and strip the leading '['
+ tmp_mod_address =
+ strndup(working_state.server_address + 1,
strlen(working_state.server_address) - 2);
+ } else {
+ tmp_mod_address = working_state.server_address;
+ }
+
int res;
- if ((res = lookup_host(working_state.server_address, addrstr,
DEFAULT_BUFFER_SIZE / 2,
+ if ((res = lookup_host(tmp_mod_address, addrstr,
DEFAULT_BUFFER_SIZE / 2,
config.sin_family))
!= 0) {
die(STATE_CRITICAL,
_("Unable to lookup IP address for '%s':
getaddrinfo returned %d - %s"),
diff --git a/plugins/check_curl.d/check_curl_helpers.h
b/plugins/check_curl.d/check_curl_helpers.h
index 87e45a9d..e7b80f7e 100644
--- a/plugins/check_curl.d/check_curl_helpers.h
+++ b/plugins/check_curl.d/check_curl_helpers.h
@@ -7,6 +7,10 @@
# include <openssl/opensslv.h>
#endif
+enum {
+ MAX_IPV4_HOSTLENGTH = 255,
+};
+
/* for buffers for header and body */
typedef struct {
size_t buflen;
