Sortix nightly manual
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CURLOPT_SSH_KEYFUNCTION(3) | libcurl | CURLOPT_SSH_KEYFUNCTION(3) |
NAME
CURLOPT_SSH_KEYFUNCTION - callback for known host matching logicSYNOPSIS
#include <curl/curl.h>
enum curl_khstat {
CURLKHSTAT_FINE_ADD_TO_FILE,
CURLKHSTAT_FINE,
CURLKHSTAT_REJECT, /* reject the connection, return an error */
CURLKHSTAT_DEFER, /* do not accept it, but we cannot answer right
now. Causes a CURLE_PEER_FAILED_VERIFICATION error but
the connection is left intact */
CURLKHSTAT_FINE_REPLACE
};
enum curl_khmatch {
CURLKHMATCH_OK, /* match */
CURLKHMATCH_MISMATCH, /* host found, key mismatch! */
CURLKHMATCH_MISSING, /* no matching host/key found */
};
struct curl_khkey {
const char *key; /* points to a null-terminated string encoded with
base64 if len is zero, otherwise to the "raw"
data */
size_t len;
enum curl_khtype keytype;
};
int ssh_keycallback(CURL *easy,
const struct curl_khkey *knownkey,
const struct curl_khkey *foundkey,
enum curl_khmatch match,
void *clientp);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KEYFUNCTION,
ssh_keycallback);
DESCRIPTION
Pass a pointer to your callback function, which should match the prototype shown above.- CURLKHSTAT_FINE_REPLACE
- The new host+key is accepted and libcurl replaces the old host+key into the known_hosts file before continuing with the connection. This also adds the new host+key combo to the known_host pool kept in memory if it was not already present there. The adding of data to the file is done by completely replacing the file with a new copy, so the permissions of the file must allow this. (Added in 7.73.0)
- CURLKHSTAT_FINE_ADD_TO_FILE
- The host+key is accepted and libcurl appends it to the known_hosts file before continuing with the connection. This also adds the host+key combo to the known_host pool kept in memory if it was not already present there. The adding of data to the file is done by completely replacing the file with a new copy, so the permissions of the file must allow this.
- CURLKHSTAT_FINE
- The host+key is accepted libcurl continues with the connection. This also adds the host+key combo to the known_host pool kept in memory if it was not already present there.
- CURLKHSTAT_REJECT
- The host+key is rejected. libcurl denies the connection to continue and it is closed.
- CURLKHSTAT_DEFER
- The host+key is rejected, but the SSH connection is asked to be kept alive. This feature could be used when the app wants to somehow return back and act on the host+key situation and then retry without needing the overhead of setting it up from scratch again.
DEFAULT
NULLPROTOCOLS
SFTP and SCPEXAMPLE
struct mine {
void *custom;
};
static int keycb(CURL *easy,
const struct curl_khkey *knownkey,
const struct curl_khkey *foundkey,
enum curl_khmatch match,
void *clientp)
{
/* 'clientp' points to the callback_data struct */
/* investigate the situation and return the correct value */
return CURLKHSTAT_FINE_ADD_TO_FILE;
}
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
struct mine callback_data;
curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/thisfile.txt");
curl_easy_setopt(curl, CURLOPT_SSH_KEYFUNCTION, keycb);
curl_easy_setopt(curl, CURLOPT_SSH_KEYDATA, &callback_data);
curl_easy_setopt(curl, CURLOPT_SSH_KNOWNHOSTS, "/home/user/known_hosts");
curl_easy_perform(curl);
}
}
AVAILABILITY
Added in 7.19.6RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.SEE ALSO
CURLOPT_SSH_KEYDATA(3), CURLOPT_SSH_KNOWNHOSTS(3)December 4, 2023 | ibcurl 8.5.0 |