CURLOPT_PROXY_PINNEDPUBLICKEY(3)

1CURLOPT_PROXY_PINNEDPUBLICKEcYu(r3l)_easy_setopt optCiUoRnLsOPT_PROXY_PINNEDPUBLICKEY(3)
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NAME

6       CURLOPT_PROXY_PINNEDPUBLICKEY - set pinned public key for https proxy
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SYNOPSIS

9       #include <curl/curl.h>
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11       CURLcode  curl_easy_setopt(CURL *handle, CURLOPT_PROXY_PINNEDPUBLICKEY,
12       char *pinnedpubkey);
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DESCRIPTION

15       Pass a pointer to a zero terminated string as parameter. The string can
16       be the file name of your pinned public key. The file format expected is
17       "PEM" or "DER".  The string can also be any number  of  base64  encoded
18       sha256 hashes preceded by "sha256//" and separated by ";"
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20       When  negotiating a TLS or SSL connection, the https proxy sends a cer‐
21       tificate indicating its identity. A public key is extracted  from  this
22       certificate and if it does not exactly match the public key provided to
23       this option, curl will abort the connection before sending or receiving
24       any data.
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26       On mismatch, CURLE_SSL_PINNEDPUBKEYNOTMATCH is returned.
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28       The  application  does not have to keep the string around after setting
29       this option.
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DEFAULT

32       NULL
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PROTOCOLS

35       All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
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EXAMPLE

38       CURL *curl = curl_easy_init();
39       if(curl) {
40         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
41         curl_easy_setopt(curl, CURLOPT_PROXY, "https://proxy:443");
42         curl_easy_setopt(curl, CURLOPT_PROXY_PINNEDPUBLICKEY,
43         "sha256//YhKJKSzoTt2b5FP18fvpHo7fJYqQCjAa3HWY3tvRMwE=;sha256//t62CeU2tQiqkexU74Gxa2eg7fRbEgoChTociMee9wno=");
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45         /* Perform the request */
46         curl_easy_perform(curl);
47       }
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PUBLIC KEY EXTRACTION

50       If you do not have the https proxy server's public  key  file  you  can
51       extract it from the https proxy server's certificate.
52       # retrieve the server's certificate if you don't already have it
53       #
54       # be sure to examine the certificate to see if it is what you expected
55       #
56       # Windows-specific:
57       # - Use NUL instead of /dev/null.
58       # - OpenSSL may wait for input instead of disconnecting. Hit enter.
59       # - If you don't have sed, then just copy the certificate into a file:
60       #   Lines from -----BEGIN CERTIFICATE----- to -----END CERTIFICATE-----.
61       #
62       openssl s_client -servername www.example.com -connect www.example.com:443 < /dev/null | sed -n "/-----BEGIN/,/-----END/p" > www.example.com.pem
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64       # extract public key in pem format from certificate
65       openssl x509 -in www.example.com.pem -pubkey -noout > www.example.com.pubkey.pem
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67       # convert public key from pem to der
68       openssl asn1parse -noout -inform pem -in www.example.com.pubkey.pem -out www.example.com.pubkey.der
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70       # sha256 hash and base64 encode der to string for use
71       openssl dgst -sha256 -binary www.example.com.pubkey.der | openssl base64
72       The  public  key  in  PEM  format  contains a header, base64 data and a
73       footer:
74       -----BEGIN PUBLIC KEY-----
75       [BASE 64 DATA]
76       -----END PUBLIC KEY-----
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AVAILABILITY

79       PEM/DER support:
80
81         7.52.0: GSKit, GnuTLS, NSS, OpenSSL, mbedtls, wolfSSL
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83       sha256 support:
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85         7.52.0: GnuTLS, NSS, OpenSSL, mbedtls, wolfSSL
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87       Other SSL backends not supported.
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RETURN VALUE

90       Returns CURLE_OK  if  TLS  enabled,  CURLE_UNKNOWN_OPTION  if  not,  or
91       CURLE_OUT_OF_MEMORY if there was insufficient heap space.
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