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<!DOCTYPE HTML> <html lang="en" class="light" dir="ltr"> <head>  <meta charset="UTF-8"> <title>Security - everything curl</title>  <meta name="description" content="everything there is to know about curl, libcurl and the cURL project"> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="theme-color" content="#ffffff"> <link rel="icon" href="../favicon.svg"> <link rel="shortcut icon" href="../favicon.png"> <link rel="stylesheet" href="../css/variables.css"> <link rel="stylesheet" href="../css/general.css"> <link rel="stylesheet" href="../css/chrome.css"> <link rel="stylesheet" href="../css/print.css" media="print">  <link rel="stylesheet" href="../FontAwesome/css/font-awesome.css"> <link rel="stylesheet" href="../fonts/fonts.css">  <link rel="stylesheet" href="../highlight.css"> <link rel="stylesheet" href="../tomorrow-night.css"> <link rel="stylesheet" href="../ayu-highlight.css">  </head> <body class="sidebar-visible no-js"> <div id="body-container">  <script> var path_to_root = "../"; var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light"; </script>  <script> try { var theme = localStorage.getItem('mdbook-theme'); var sidebar = localStorage.getItem('mdbook-sidebar'); if (theme.startsWith('"') && theme.endsWith('"')) { localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1)); } if (sidebar.startsWith('"') && sidebar.endsWith('"')) { localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1)); } } catch (e) { } </script>  <script> var theme; try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { } if (theme === null || theme === undefined) { theme = default_theme; } var html = document.querySelector('html'); html.classList.remove('light') html.classList.add(theme); var body = document.querySelector('body'); body.classList.remove('no-js') body.classList.add('js'); </script> <input type="checkbox" id="sidebar-toggle-anchor" class="hidden">  <script> var body = document.querySelector('body'); var sidebar = null; var sidebar_toggle = document.getElementById("sidebar-toggle-anchor"); if (document.body.clientWidth >= 1080) { try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { } sidebar = sidebar || 'visible'; } else { sidebar = 'hidden'; } sidebar_toggle.checked = sidebar === 'visible'; body.classList.remove('sidebar-visible'); body.classList.add("sidebar-" + sidebar); </script> <nav id="sidebar" class="sidebar" aria-label="Table of contents"> <div class="sidebar-scrollbox"> <ol class="chapter"><li class="chapter-item "><a href="../index.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item "><a href="../how-to-read.html"><strong aria-hidden="true">2.</strong> How to read</a></li><li class="chapter-item expanded "><a href="../project/index.html"><strong aria-hidden="true">3.</strong> The cURL project</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../project/started.html"><strong aria-hidden="true">3.1.</strong> How it started</a></li><li class="chapter-item "><a href="../project/name.html"><strong aria-hidden="true">3.2.</strong> The name</a></li><li class="chapter-item "><a href="../project/does.html"><strong aria-hidden="true">3.3.</strong> What does curl do?</a></li><li class="chapter-item "><a href="../project/comm.html"><strong aria-hidden="true">3.4.</strong> Project communication</a></li><li class="chapter-item "><a href="../project/etiquette.html"><strong aria-hidden="true">3.5.</strong> Mailing list etiquette</a></li><li class="chapter-item "><a href="../project/maillists.html"><strong aria-hidden="true">3.6.</strong> Mailing lists</a></li><li class="chapter-item "><a href="../project/bugs.html"><strong aria-hidden="true">3.7.</strong> Reporting bugs</a></li><li class="chapter-item "><a href="../project/support.html"><strong aria-hidden="true">3.8.</strong> Commercial support</a></li><li class="chapter-item "><a href="../project/releases.html"><strong aria-hidden="true">3.9.</strong> Releases</a></li><li class="chapter-item expanded "><a href="../project/security.html" class="active"><strong aria-hidden="true">3.10.</strong> Security</a></li><li class="chapter-item "><a href="../project/trust.html"><strong aria-hidden="true">3.11.</strong> Trust</a></li><li class="chapter-item "><a href="../project/coc.html"><strong aria-hidden="true">3.12.</strong> Code of Conduct</a></li><li class="chapter-item "><a href="../project/devel.html"><strong aria-hidden="true">3.13.</strong> Development</a></li><li class="chapter-item "><a href="../project/devteam.html"><strong aria-hidden="true">3.14.</strong> The development team</a></li><li class="chapter-item "><a href="../project/users.html"><strong aria-hidden="true">3.15.</strong> Users of curl</a></li><li class="chapter-item "><a href="../project/future.html"><strong aria-hidden="true">3.16.</strong> Future</a></li></ol></li><li class="chapter-item "><a href="../protocols/index.html"><strong aria-hidden="true">4.</strong> Network and protocols</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../protocols/network.html"><strong aria-hidden="true">4.1.</strong> Networking simplified</a></li><li class="chapter-item "><a href="../protocols/protocols.html"><strong aria-hidden="true">4.2.</strong> Protocols</a></li><li class="chapter-item "><a href="../protocols/curl.html"><strong aria-hidden="true">4.3.</strong> curl protocols</a></li><li class="chapter-item "><a href="../protocols/http.html"><strong aria-hidden="true">4.4.</strong> HTTP basics</a></li></ol></li><li class="chapter-item "><a href="../install/index.html"><strong aria-hidden="true">5.</strong> Install curl and libcurl</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../install/linux.html"><strong aria-hidden="true">5.1.</strong> Linux</a></li><li class="chapter-item "><a href="../install/windows/index.html"><strong aria-hidden="true">5.2.</strong> Windows</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../install/windows/win-msys2.html"><strong aria-hidden="true">5.2.1.</strong> MSYS2</a></li><li class="chapter-item "><a href="../install/windows/win-vcpkg.html"><strong aria-hidden="true">5.2.2.</strong> vcpkg</a></li></ol></li><li class="chapter-item "><a href="../install/macos.html"><strong aria-hidden="true">5.3.</strong> macOS</a></li><li class="chapter-item "><a href="../install/container.html"><strong aria-hidden="true">5.4.</strong> Container</a></li></ol></li><li class="chapter-item "><a href="../source/index.html"><strong aria-hidden="true">6.</strong> Source code</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../source/opensource/index.html"><strong aria-hidden="true">6.1.</strong> Open Source</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../source/opensource/license.html"><strong aria-hidden="true">6.1.1.</strong> License</a></li><li class="chapter-item "><a href="../source/opensource/copyright.html"><strong aria-hidden="true">6.1.2.</strong> Copyright</a></li></ol></li><li class="chapter-item "><a href="../source/layout.html"><strong aria-hidden="true">6.2.</strong> Code layout</a></li><li class="chapter-item "><a href="../source/options.html"><strong aria-hidden="true">6.3.</strong> Handling build options</a></li><li class="chapter-item "><a href="../source/style.html"><strong aria-hidden="true">6.4.</strong> Code style</a></li><li class="chapter-item "><a href="../source/contributing.html"><strong aria-hidden="true">6.5.</strong> Contributing</a></li><li class="chapter-item "><a href="../source/reportvuln.html"><strong aria-hidden="true">6.6.</strong> Reporting vulnerabilities</a></li><li class="chapter-item "><a href="../source/web.html"><strong aria-hidden="true">6.7.</strong> Website</a></li></ol></li><li class="chapter-item "><a href="../build/index.html"><strong aria-hidden="true">7.</strong> Build curl and libcurl</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../build/autotools.html"><strong aria-hidden="true">7.1.</strong> Autotools</a></li><li class="chapter-item "><a href="../build/cmake.html"><strong aria-hidden="true">7.2.</strong> CMake</a></li><li class="chapter-item "><a href="../build/separate.html"><strong aria-hidden="true">7.3.</strong> Separate install</a></li><li class="chapter-item "><a href="../build/windows.html"><strong aria-hidden="true">7.4.</strong> Windows</a></li><li class="chapter-item "><a href="../build/deps.html"><strong aria-hidden="true">7.5.</strong> Dependencies</a></li><li class="chapter-item "><a href="../build/tls.html"><strong aria-hidden="true">7.6.</strong> TLS libraries</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../build/boringssl.html"><strong aria-hidden="true">7.6.1.</strong> BoringSSL</a></li></ol></li></ol></li><li class="chapter-item "><a href="../cmdline/index.html"><strong aria-hidden="true">8.</strong> Command line concepts</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cmdline/differences.html"><strong aria-hidden="true">8.1.</strong> Differences</a></li><li class="chapter-item "><a href="../cmdline/options/index.html"><strong aria-hidden="true">8.2.</strong> Command line options</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cmdline/options/short.html"><strong aria-hidden="true">8.2.1.</strong> Short options</a></li><li class="chapter-item "><a href="../cmdline/options/long.html"><strong aria-hidden="true">8.2.2.</strong> Long options</a></li><li class="chapter-item "><a href="../cmdline/options/args.html"><strong aria-hidden="true">8.2.3.</strong> Arguments to options</a></li><li class="chapter-item "><a href="../cmdline/options/negative.html"><strong aria-hidden="true">8.2.4.</strong> Negative options</a></li></ol></li><li class="chapter-item "><a href="../cmdline/versions.html"><strong aria-hidden="true">8.3.</strong> Options depend on version</a></li><li class="chapter-item "><a href="../cmdline/urls/index.html"><strong aria-hidden="true">8.4.</strong> URLs</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cmdline/urls/scheme.html"><strong aria-hidden="true">8.4.1.</strong> Scheme</a></li><li class="chapter-item "><a href="../cmdline/urls/auth.html"><strong aria-hidden="true">8.4.2.</strong> Name and password</a></li><li class="chapter-item "><a href="../cmdline/urls/host.html"><strong aria-hidden="true">8.4.3.</strong> Host</a></li><li class="chapter-item "><a href="../cmdline/urls/port.html"><strong aria-hidden="true">8.4.4.</strong> Port number</a></li><li class="chapter-item "><a href="../cmdline/urls/path.html"><strong aria-hidden="true">8.4.5.</strong> Path</a></li><li class="chapter-item "><a href="../cmdline/urls/query.html"><strong aria-hidden="true">8.4.6.</strong> Query</a></li><li class="chapter-item "><a href="../cmdline/urls/ftptype.html"><strong aria-hidden="true">8.4.7.</strong> FTP type</a></li><li class="chapter-item "><a href="../cmdline/urls/fragment.html"><strong aria-hidden="true">8.4.8.</strong> Fragment</a></li><li class="chapter-item "><a href="../cmdline/urls/browsers.html"><strong aria-hidden="true">8.4.9.</strong> Browsers</a></li><li class="chapter-item "><a href="../cmdline/urls/options.html"><strong aria-hidden="true">8.4.10.</strong> Many options and URLs</a></li><li class="chapter-item "><a href="../cmdline/urls/globbing.html"><strong aria-hidden="true">8.4.11.</strong> URL globbing</a></li><li class="chapter-item "><a href="../cmdline/urls/connreuse.html"><strong aria-hidden="true">8.4.12.</strong> Connection reuse</a></li><li class="chapter-item "><a href="../cmdline/urls/parallel.html"><strong aria-hidden="true">8.4.13.</strong> Parallel transfers</a></li><li class="chapter-item "><a href="../cmdline/urls/trurl.html"><strong aria-hidden="true">8.4.14.</strong> trurl</a></li></ol></li><li class="chapter-item "><a href="../cmdline/listopts.html"><strong aria-hidden="true">8.5.</strong> List options</a></li><li class="chapter-item "><a href="../cmdline/configfile.html"><strong aria-hidden="true">8.6.</strong> Config file</a></li><li class="chapter-item "><a href="../cmdline/variables.html"><strong aria-hidden="true">8.7.</strong> Variables</a></li><li class="chapter-item "><a href="../cmdline/passwords.html"><strong aria-hidden="true">8.8.</strong> Passwords</a></li><li class="chapter-item "><a href="../cmdline/progressmeter.html"><strong aria-hidden="true">8.9.</strong> Progress meter</a></li><li class="chapter-item "><a href="../cmdline/curlver.html"><strong aria-hidden="true">8.10.</strong> Version</a></li><li class="chapter-item "><a href="../cmdline/exitcode.html"><strong aria-hidden="true">8.11.</strong> Exit code</a></li><li class="chapter-item "><a href="../cmdline/copyas.html"><strong aria-hidden="true">8.12.</strong> Copy as curl</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/index.html"><strong aria-hidden="true">9.</strong> Command line transfers</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/verbose/index.html"><strong aria-hidden="true">9.1.</strong> Verbose</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/verbose/trace.html"><strong aria-hidden="true">9.1.1.</strong> Trace options</a></li><li class="chapter-item "><a href="../usingcurl/verbose/writeout.html"><strong aria-hidden="true">9.1.2.</strong> Write out</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/downloads/index.html"><strong aria-hidden="true">9.2.</strong> Downloads</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/downloads/whatis.html"><strong aria-hidden="true">9.2.1.</strong> What is downloading?</a></li><li class="chapter-item "><a href="../usingcurl/downloads/storing.html"><strong aria-hidden="true">9.2.2.</strong> Storing downloads</a></li><li class="chapter-item "><a href="../usingcurl/downloads/url-named.html"><strong aria-hidden="true">9.2.3.</strong> Download to a file named by the URL</a></li><li class="chapter-item "><a href="../usingcurl/downloads/content-disp.html"><strong aria-hidden="true">9.2.4.</strong> Use the target filename from the server</a></li><li class="chapter-item "><a href="../usingcurl/downloads/charsets.html"><strong aria-hidden="true">9.2.5.</strong> HTML and charsets</a></li><li class="chapter-item "><a href="../usingcurl/downloads/redirects.html"><strong aria-hidden="true">9.2.6.</strong> Shell redirects</a></li><li class="chapter-item "><a href="../usingcurl/downloads/multiple.html"><strong aria-hidden="true">9.2.7.</strong> Multiple downloads</a></li><li class="chapter-item "><a href="../usingcurl/downloads/browsers.html"><strong aria-hidden="true">9.2.8.</strong> My browser shows something else</a></li><li class="chapter-item "><a href="../usingcurl/downloads/max-filesize.html"><strong aria-hidden="true">9.2.9.</strong> Maximum filesize</a></li><li class="chapter-item "><a href="../usingcurl/downloads/metadata-fs.html"><strong aria-hidden="true">9.2.10.</strong> Storing metadata in file system</a></li><li class="chapter-item "><a href="../usingcurl/downloads/raw.html"><strong aria-hidden="true">9.2.11.</strong> Raw</a></li><li class="chapter-item "><a href="../usingcurl/downloads/retry.html"><strong aria-hidden="true">9.2.12.</strong> Retry</a></li><li class="chapter-item "><a href="../usingcurl/downloads/resume.html"><strong aria-hidden="true">9.2.13.</strong> Resuming and ranges</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/uploads.html"><strong aria-hidden="true">9.3.</strong> Uploads</a></li><li class="chapter-item "><a href="../usingcurl/transfers/index.html"><strong aria-hidden="true">9.4.</strong> Transfer controls</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/transfers/tooslow.html"><strong aria-hidden="true">9.4.1.</strong> Stop slow transfers</a></li><li class="chapter-item "><a href="../usingcurl/transfers/rate-limiting.html"><strong aria-hidden="true">9.4.2.</strong> Rate limiting</a></li><li class="chapter-item "><a href="../usingcurl/transfers/request-rate.html"><strong aria-hidden="true">9.4.3.</strong> Request rate limiting</a></li><li class="chapter-item "><a href="../usingcurl/transfers/compression.html"><strong aria-hidden="true">9.4.4.</strong> Compression</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/connections/index.html"><strong aria-hidden="true">9.5.</strong> Connections</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/connections/name.html"><strong aria-hidden="true">9.5.1.</strong> Name resolve tricks</a></li><li class="chapter-item "><a href="../usingcurl/connections/timeout.html"><strong aria-hidden="true">9.5.2.</strong> Connection timeout</a></li><li class="chapter-item "><a href="../usingcurl/connections/happy.html"><strong aria-hidden="true">9.5.3.</strong> Happy Eyeballs</a></li><li class="chapter-item "><a href="../usingcurl/connections/interface.html"><strong aria-hidden="true">9.5.4.</strong> Network interface</a></li><li class="chapter-item "><a href="../usingcurl/connections/local-port.html"><strong aria-hidden="true">9.5.5.</strong> Local port number</a></li><li class="chapter-item "><a href="../usingcurl/connections/keepalive.html"><strong aria-hidden="true">9.5.6.</strong> Keep alive</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/timeouts.html"><strong aria-hidden="true">9.6.</strong> Timeouts</a></li><li class="chapter-item "><a href="../usingcurl/netrc.html"><strong aria-hidden="true">9.7.</strong> .netrc</a></li><li class="chapter-item "><a href="../usingcurl/proxies/index.html"><strong aria-hidden="true">9.8.</strong> Proxies</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/proxies/discover.html"><strong aria-hidden="true">9.8.1.</strong> Discover your proxy</a></li><li class="chapter-item "><a href="../usingcurl/proxies/pac.html"><strong aria-hidden="true">9.8.2.</strong> PAC</a></li><li class="chapter-item "><a href="../usingcurl/proxies/captive.html"><strong aria-hidden="true">9.8.3.</strong> Captive portals</a></li><li class="chapter-item "><a href="../usingcurl/proxies/type.html"><strong aria-hidden="true">9.8.4.</strong> Proxy type</a></li><li class="chapter-item "><a href="../usingcurl/proxies/http.html"><strong aria-hidden="true">9.8.5.</strong> HTTP proxy</a></li><li class="chapter-item "><a href="../usingcurl/proxies/socks.html"><strong aria-hidden="true">9.8.6.</strong> SOCKS proxy</a></li><li class="chapter-item "><a href="../usingcurl/proxies/mitm.html"><strong aria-hidden="true">9.8.7.</strong> MITM proxy</a></li><li class="chapter-item "><a href="../usingcurl/proxies/auth.html"><strong aria-hidden="true">9.8.8.</strong> Proxy authentication</a></li><li class="chapter-item "><a href="../usingcurl/proxies/https.html"><strong aria-hidden="true">9.8.9.</strong> HTTPS proxy</a></li><li class="chapter-item "><a href="../usingcurl/proxies/env.html"><strong aria-hidden="true">9.8.10.</strong> Proxy environment variables</a></li><li class="chapter-item "><a href="../usingcurl/proxies/headers.html"><strong aria-hidden="true">9.8.11.</strong> Proxy headers</a></li><li class="chapter-item "><a href="../usingcurl/proxies/haproxy.html"><strong aria-hidden="true">9.8.12.</strong> haproxy</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/tls.html"><strong aria-hidden="true">9.9.</strong> TLS</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/tls/ciphers.html"><strong aria-hidden="true">9.9.1.</strong> Ciphers</a></li><li class="chapter-item "><a href="../usingcurl/tls/enable.html"><strong aria-hidden="true">9.9.2.</strong> Enable TLS</a></li><li class="chapter-item "><a href="../usingcurl/tls/versions.html"><strong aria-hidden="true">9.9.3.</strong> TLS versions</a></li><li class="chapter-item "><a href="../usingcurl/tls/verify.html"><strong aria-hidden="true">9.9.4.</strong> Verifying server certificates</a></li><li class="chapter-item "><a href="../usingcurl/tls/pinning.html"><strong aria-hidden="true">9.9.5.</strong> Certificate pinning</a></li><li class="chapter-item "><a href="../usingcurl/tls/stapling.html"><strong aria-hidden="true">9.9.6.</strong> OCSP stapling</a></li><li class="chapter-item "><a href="../usingcurl/tls/clientcert.html"><strong aria-hidden="true">9.9.7.</strong> Client certificates</a></li><li class="chapter-item "><a href="../usingcurl/tls/auth.html"><strong aria-hidden="true">9.9.8.</strong> TLS auth</a></li><li class="chapter-item "><a href="../usingcurl/tls/backends.html"><strong aria-hidden="true">9.9.9.</strong> TLS backends</a></li><li class="chapter-item "><a href="../usingcurl/tls/sslkeylogfile.html"><strong aria-hidden="true">9.9.10.</strong> SSLKEYLOGFILE</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/ssh/index.html"><strong aria-hidden="true">9.10.</strong> SCP and SFTP</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usingcurl/ssh/url.html"><strong aria-hidden="true">9.10.1.</strong> URLs</a></li><li class="chapter-item "><a href="../usingcurl/ssh/auth.html"><strong aria-hidden="true">9.10.2.</strong> Authentication</a></li><li class="chapter-item "><a href="../usingcurl/ssh/knownhosts.html"><strong aria-hidden="true">9.10.3.</strong> Known hosts</a></li></ol></li><li class="chapter-item "><a href="../usingcurl/reademail.html"><strong aria-hidden="true">9.11.</strong> Reading email</a></li><li class="chapter-item "><a href="../usingcurl/smtp.html"><strong aria-hidden="true">9.12.</strong> Sending email</a></li><li class="chapter-item "><a href="../usingcurl/dict.html"><strong aria-hidden="true">9.13.</strong> DICT</a></li><li class="chapter-item "><a href="../usingcurl/ipfs.html"><strong aria-hidden="true">9.14.</strong> IPFS</a></li><li class="chapter-item "><a href="../usingcurl/mqtt.html"><strong aria-hidden="true">9.15.</strong> MQTT</a></li><li class="chapter-item "><a href="../usingcurl/telnet.html"><strong aria-hidden="true">9.16.</strong> TELNET</a></li><li class="chapter-item "><a href="../usingcurl/tftp.html"><strong aria-hidden="true">9.17.</strong> TFTP</a></li></ol></li><li class="chapter-item "><a href="../http/index.html"><strong aria-hidden="true">10.</strong> Command line HTTP</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/method.html"><strong aria-hidden="true">10.1.</strong> Method</a></li><li class="chapter-item "><a href="../http/response.html"><strong aria-hidden="true">10.2.</strong> Responses</a></li><li class="chapter-item "><a href="../http/auth.html"><strong aria-hidden="true">10.3.</strong> Authentication</a></li><li class="chapter-item "><a href="../http/versions/index.html"><strong aria-hidden="true">10.4.</strong> HTTP versions</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/versions/http09.html"><strong aria-hidden="true">10.4.1.</strong> HTTP/0.9</a></li><li class="chapter-item "><a href="../http/versions/http2.html"><strong aria-hidden="true">10.4.2.</strong> HTTP/2</a></li><li class="chapter-item "><a href="../http/versions/http3.html"><strong aria-hidden="true">10.4.3.</strong> HTTP/3</a></li></ol></li><li class="chapter-item "><a href="../http/post/index.html"><strong aria-hidden="true">10.5.</strong> HTTP POST</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/post/simple.html"><strong aria-hidden="true">10.5.1.</strong> Simple POST</a></li><li class="chapter-item "><a href="../http/post/content-type.html"><strong aria-hidden="true">10.5.2.</strong> Content-Type</a></li><li class="chapter-item "><a href="../http/post/binary.html"><strong aria-hidden="true">10.5.3.</strong> Posting binary</a></li><li class="chapter-item "><a href="../http/post/json.html"><strong aria-hidden="true">10.5.4.</strong> JSON</a></li><li class="chapter-item "><a href="../http/post/url-encode.html"><strong aria-hidden="true">10.5.5.</strong> URL encode data</a></li><li class="chapter-item "><a href="../http/post/convert-to-get.html"><strong aria-hidden="true">10.5.6.</strong> Convert to GET</a></li><li class="chapter-item "><a href="../http/post/expect100.html"><strong aria-hidden="true">10.5.7.</strong> Expect 100-continue</a></li><li class="chapter-item "><a href="../http/post/chunked.html"><strong aria-hidden="true">10.5.8.</strong> Chunked encoded POSTs</a></li><li class="chapter-item "><a href="../http/post/hiddenfields.html"><strong aria-hidden="true">10.5.9.</strong> Hidden form fields</a></li><li class="chapter-item "><a href="../http/post/browsersends.html"><strong aria-hidden="true">10.5.10.</strong> Figure out what a browser sends</a></li><li class="chapter-item "><a href="../http/post/javascript.html"><strong aria-hidden="true">10.5.11.</strong> JavaScript and forms</a></li><li class="chapter-item "><a href="../http/post/multipart.html"><strong aria-hidden="true">10.5.12.</strong> Multipart formposts</a></li><li class="chapter-item "><a href="../http/post/postvspost.html"><strong aria-hidden="true">10.5.13.</strong> -d vs -F</a></li></ol></li><li class="chapter-item "><a href="../http/put.html"><strong aria-hidden="true">10.6.</strong> HTTP PUT</a></li><li class="chapter-item "><a href="../http/redirects.html"><strong aria-hidden="true">10.7.</strong> Redirects</a></li><li class="chapter-item "><a href="../http/modify/index.html"><strong aria-hidden="true">10.8.</strong> Customize your HTTP</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/modify/method.html"><strong aria-hidden="true">10.8.1.</strong> Request method</a></li><li class="chapter-item "><a href="../http/modify/target.html"><strong aria-hidden="true">10.8.2.</strong> Request target</a></li><li class="chapter-item "><a href="../http/modify/fragment.html"><strong aria-hidden="true">10.8.3.</strong> Fragment</a></li><li class="chapter-item "><a href="../http/modify/headers.html"><strong aria-hidden="true">10.8.4.</strong> Customize headers</a></li><li class="chapter-item "><a href="../http/modify/referer.html"><strong aria-hidden="true">10.8.5.</strong> Referer</a></li><li class="chapter-item "><a href="../http/modify/user-agent.html"><strong aria-hidden="true">10.8.6.</strong> User-agent</a></li><li class="chapter-item "><a href="../http/modify/ranges.html"><strong aria-hidden="true">10.8.7.</strong> Ranges</a></li><li class="chapter-item "><a href="../http/modify/conditionals.html"><strong aria-hidden="true">10.8.8.</strong> Conditionals</a></li><li class="chapter-item "><a href="../http/modify/compression.html"><strong aria-hidden="true">10.8.9.</strong> Compression</a></li></ol></li><li class="chapter-item "><a href="../http/cookies/index.html"><strong aria-hidden="true">10.9.</strong> Cookies</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/cookies/engine.html"><strong aria-hidden="true">10.9.1.</strong> Cookie engine</a></li><li class="chapter-item "><a href="../http/cookies/reading.html"><strong aria-hidden="true">10.9.2.</strong> Reading cookies from file</a></li><li class="chapter-item "><a href="../http/cookies/writing.html"><strong aria-hidden="true">10.9.3.</strong> Writing cookies to file</a></li><li class="chapter-item "><a href="../http/cookies/newsession.html"><strong aria-hidden="true">10.9.4.</strong> New cookie session</a></li><li class="chapter-item "><a href="../http/cookies/fileformat.html"><strong aria-hidden="true">10.9.5.</strong> Cookie file format</a></li></ol></li><li class="chapter-item "><a href="../http/https.html"><strong aria-hidden="true">10.10.</strong> HTTPS</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../http/https/hsts.html"><strong aria-hidden="true">10.10.1.</strong> HSTS</a></li><li class="chapter-item "><a href="../http/https/altsvc.html"><strong aria-hidden="true">10.10.2.</strong> Alternative Services</a></li></ol></li><li class="chapter-item "><a href="../http/browserlike.html"><strong aria-hidden="true">10.11.</strong> Scripting browser-like tasks</a></li></ol></li><li class="chapter-item "><a href="../ftp/index.html"><strong aria-hidden="true">11.</strong> Command line FTP</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../ftp/dirlist.html"><strong aria-hidden="true">11.1.</strong> FTP Directory listing</a></li><li class="chapter-item "><a href="../ftp/upload.html"><strong aria-hidden="true">11.2.</strong> Uploading with FTP</a></li><li class="chapter-item "><a href="../ftp/cmds.html"><strong aria-hidden="true">11.3.</strong> Custom FTP commands</a></li><li class="chapter-item "><a href="../ftp/twoconnections.html"><strong aria-hidden="true">11.4.</strong> Two connections</a></li><li class="chapter-item "><a href="../ftp/traversedir.html"><strong aria-hidden="true">11.5.</strong> Directory traversing</a></li><li class="chapter-item "><a href="../ftp/ftps.html"><strong aria-hidden="true">11.6.</strong> FTPS</a></li></ol></li><li class="chapter-item "><a href="../libcurl/index.html"><strong aria-hidden="true">12.</strong> libcurl</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../libcurl/headers.html"><strong aria-hidden="true">12.1.</strong> Header files</a></li><li class="chapter-item "><a href="../libcurl/globalinit.html"><strong aria-hidden="true">12.2.</strong> Global initialization</a></li><li class="chapter-item "><a href="../libcurl/api.html"><strong aria-hidden="true">12.3.</strong> API compatibility</a></li><li class="chapter-item "><a href="../libcurl/--libcurl.html"><strong aria-hidden="true">12.4.</strong> --libcurl</a></li><li class="chapter-item "><a href="../libcurl/threading.html"><strong aria-hidden="true">12.5.</strong> multi-threading</a></li><li class="chapter-item "><a href="../libcurl/curlcode.html"><strong aria-hidden="true">12.6.</strong> CURLcode return codes</a></li><li class="chapter-item "><a href="../libcurl/verbose.html"><strong aria-hidden="true">12.7.</strong> Verbose operations</a></li><li class="chapter-item "><a href="../libcurl/caches.html"><strong aria-hidden="true">12.8.</strong> Caches</a></li><li class="chapter-item "><a href="../libcurl/performance.html"><strong aria-hidden="true">12.9.</strong> Performance</a></li><li class="chapter-item "><a href="../libcurl/cplusplus.html"><strong aria-hidden="true">12.10.</strong> for C++ programmers</a></li></ol></li><li class="chapter-item "><a href="../transfers/index.html"><strong aria-hidden="true">13.</strong> libcurl transfers</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/easyhandle.html"><strong aria-hidden="true">13.1.</strong> Easy handle</a></li><li class="chapter-item "><a href="../transfers/options/index.html"><strong aria-hidden="true">13.2.</strong> curl easy options</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/options/num.html"><strong aria-hidden="true">13.2.1.</strong> Set numerical options</a></li><li class="chapter-item "><a href="../transfers/options/strings.html"><strong aria-hidden="true">13.2.2.</strong> Set string options</a></li><li class="chapter-item "><a href="../transfers/options/tls.html"><strong aria-hidden="true">13.2.3.</strong> TLS options</a></li><li class="chapter-item "><a href="../transfers/options/all.html"><strong aria-hidden="true">13.2.4.</strong> All options</a></li><li class="chapter-item "><a href="../transfers/options/info.html"><strong aria-hidden="true">13.2.5.</strong> Get option information</a></li></ol></li><li class="chapter-item "><a href="../transfers/drive/index.html"><strong aria-hidden="true">13.3.</strong> Drive transfers</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/drive/easy.html"><strong aria-hidden="true">13.3.1.</strong> Drive with easy</a></li><li class="chapter-item "><a href="../transfers/drive/multi.html"><strong aria-hidden="true">13.3.2.</strong> Drive with multi</a></li><li class="chapter-item "><a href="../transfers/drive/multi-socket.html"><strong aria-hidden="true">13.3.3.</strong> Drive with multi_socket</a></li></ol></li><li class="chapter-item "><a href="../transfers/callbacks/index.html"><strong aria-hidden="true">13.4.</strong> Callbacks</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/callbacks/write.html"><strong aria-hidden="true">13.4.1.</strong> Write data</a></li><li class="chapter-item "><a href="../transfers/callbacks/read.html"><strong aria-hidden="true">13.4.2.</strong> Read data</a></li><li class="chapter-item "><a href="../transfers/callbacks/progress.html"><strong aria-hidden="true">13.4.3.</strong> Progress information</a></li><li class="chapter-item "><a href="../transfers/callbacks/header.html"><strong aria-hidden="true">13.4.4.</strong> Header data</a></li><li class="chapter-item "><a href="../transfers/callbacks/debug.html"><strong aria-hidden="true">13.4.5.</strong> Debug</a></li><li class="chapter-item "><a href="../transfers/callbacks/sockopt.html"><strong aria-hidden="true">13.4.6.</strong> sockopt</a></li><li class="chapter-item "><a href="../transfers/callbacks/sslcontext.html"><strong aria-hidden="true">13.4.7.</strong> SSL context</a></li><li class="chapter-item "><a href="../transfers/callbacks/seek.html"><strong aria-hidden="true">13.4.8.</strong> Seek and ioctl</a></li><li class="chapter-item "><a href="../transfers/callbacks/conversions.html"><strong aria-hidden="true">13.4.9.</strong> Network data conversion</a></li><li class="chapter-item "><a href="../transfers/callbacks/openclosesocket.html"><strong aria-hidden="true">13.4.10.</strong> Opensocket and closesocket</a></li><li class="chapter-item "><a href="../transfers/callbacks/sshkey.html"><strong aria-hidden="true">13.4.11.</strong> SSH key</a></li><li class="chapter-item "><a href="../transfers/callbacks/rtsp.html"><strong aria-hidden="true">13.4.12.</strong> RTSP interleaved data</a></li><li class="chapter-item "><a href="../transfers/callbacks/ftpmatch.html"><strong aria-hidden="true">13.4.13.</strong> FTP wildcard matching</a></li><li class="chapter-item "><a href="../transfers/callbacks/resolver.html"><strong aria-hidden="true">13.4.14.</strong> Resolver start</a></li><li class="chapter-item "><a href="../transfers/callbacks/trailers.html"><strong aria-hidden="true">13.4.15.</strong> Sending trailers</a></li><li class="chapter-item "><a href="../transfers/callbacks/hsts.html"><strong aria-hidden="true">13.4.16.</strong> HSTS</a></li><li class="chapter-item "><a href="../transfers/callbacks/prereq.html"><strong aria-hidden="true">13.4.17.</strong> Prereq</a></li></ol></li><li class="chapter-item "><a href="../transfers/conn/index.html"><strong aria-hidden="true">13.5.</strong> Connection control</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/conn/how.html"><strong aria-hidden="true">13.5.1.</strong> How libcurl connects</a></li><li class="chapter-item "><a href="../transfers/conn/local.html"><strong aria-hidden="true">13.5.2.</strong> Local address and port number</a></li><li class="chapter-item "><a href="../transfers/conn/reuse.html"><strong aria-hidden="true">13.5.3.</strong> Connection reuse</a></li><li class="chapter-item "><a href="../transfers/conn/keepalive.html"><strong aria-hidden="true">13.5.4.</strong> Keep alive</a></li><li class="chapter-item "><a href="../transfers/conn/names.html"><strong aria-hidden="true">13.5.5.</strong> Name resolving</a></li><li class="chapter-item "><a href="../transfers/conn/proxies.html"><strong aria-hidden="true">13.5.6.</strong> Proxies</a></li></ol></li><li class="chapter-item "><a href="../transfers/control/index.html"><strong aria-hidden="true">13.6.</strong> Transfer control</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../transfers/control/stop.html"><strong aria-hidden="true">13.6.1.</strong> Stop</a></li><li class="chapter-item "><a href="../transfers/control/stopslow.html"><strong aria-hidden="true">13.6.2.</strong> Stop slow transfers</a></li><li class="chapter-item "><a href="../transfers/control/ratelimit.html"><strong aria-hidden="true">13.6.3.</strong> Rate limit</a></li><li class="chapter-item "><a href="../transfers/control/meter.html"><strong aria-hidden="true">13.6.4.</strong> Progress meter</a></li><li class="chapter-item "><a href="../transfers/control/progress-callback.html"><strong aria-hidden="true">13.6.5.</strong> Progress callback</a></li></ol></li><li class="chapter-item "><a href="../transfers/auth.html"><strong aria-hidden="true">13.7.</strong> Authentication</a></li><li class="chapter-item "><a href="../transfers/cleanup.html"><strong aria-hidden="true">13.8.</strong> Cleanup</a></li><li class="chapter-item "><a href="../transfers/getinfo.html"><strong aria-hidden="true">13.9.</strong> Post transfer info</a></li></ol></li><li class="chapter-item "><a href="../libcurl-http/index.html"><strong aria-hidden="true">14.</strong> libcurl HTTP</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../libcurl-http/responses.html"><strong aria-hidden="true">14.1.</strong> Responses</a></li><li class="chapter-item "><a href="../libcurl-http/requests.html"><strong aria-hidden="true">14.2.</strong> Requests</a></li><li class="chapter-item "><a href="../libcurl-http/versions.html"><strong aria-hidden="true">14.3.</strong> Versions</a></li><li class="chapter-item "><a href="../libcurl-http/ranges.html"><strong aria-hidden="true">14.4.</strong> Ranges</a></li><li class="chapter-item "><a href="../libcurl-http/auth.html"><strong aria-hidden="true">14.5.</strong> Authentication</a></li><li class="chapter-item "><a href="../libcurl-http/cookies.html"><strong aria-hidden="true">14.6.</strong> Cookies</a></li><li class="chapter-item "><a href="../libcurl-http/download.html"><strong aria-hidden="true">14.7.</strong> Download</a></li><li class="chapter-item "><a href="../libcurl-http/upload.html"><strong aria-hidden="true">14.8.</strong> Upload</a></li><li class="chapter-item "><a href="../libcurl-http/multiplexing.html"><strong aria-hidden="true">14.9.</strong> Multiplexing</a></li><li class="chapter-item "><a href="../libcurl-http/hsts.html"><strong aria-hidden="true">14.10.</strong> HSTS</a></li><li class="chapter-item "><a href="../libcurl-http/alt-svc.html"><strong aria-hidden="true">14.11.</strong> alt-svc</a></li></ol></li><li class="chapter-item "><a href="../helpers/index.html"><strong aria-hidden="true">15.</strong> libcurl helpers</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../helpers/sharing.html"><strong aria-hidden="true">15.1.</strong> Share data between handles</a></li><li class="chapter-item "><a href="../helpers/url/index.html"><strong aria-hidden="true">15.2.</strong> URL API</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../helpers/url/include.html"><strong aria-hidden="true">15.2.1.</strong> Include files</a></li><li class="chapter-item "><a href="../helpers/url/init.html"><strong aria-hidden="true">15.2.2.</strong> Create, cleanup, duplicate</a></li><li class="chapter-item "><a href="../helpers/url/parse.html"><strong aria-hidden="true">15.2.3.</strong> Parse a URL</a></li><li class="chapter-item "><a href="../helpers/url/redirect.html"><strong aria-hidden="true">15.2.4.</strong> Redirect to URL</a></li><li class="chapter-item "><a href="../helpers/url/get.html"><strong aria-hidden="true">15.2.5.</strong> Get a URL</a></li><li class="chapter-item "><a href="../helpers/url/get-part.html"><strong aria-hidden="true">15.2.6.</strong> Get URL parts</a></li><li class="chapter-item "><a href="../helpers/url/set-part.html"><strong aria-hidden="true">15.2.7.</strong> Set URL parts</a></li><li class="chapter-item "><a href="../helpers/url/append-query.html"><strong aria-hidden="true">15.2.8.</strong> Append to the query</a></li><li class="chapter-item "><a href="../helpers/url/setopt.html"><strong aria-hidden="true">15.2.9.</strong> CURLOPT_CURLU</a></li></ol></li><li class="chapter-item "><a href="../helpers/ws/index.html"><strong aria-hidden="true">15.3.</strong> WebSocket</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../helpers/ws/support.html"><strong aria-hidden="true">15.3.1.</strong> Support</a></li><li class="chapter-item "><a href="../helpers/ws/urls.html"><strong aria-hidden="true">15.3.2.</strong> URLs</a></li><li class="chapter-item "><a href="../helpers/ws/concept.html"><strong aria-hidden="true">15.3.3.</strong> Concept</a></li><li class="chapter-item "><a href="../helpers/ws/options.html"><strong aria-hidden="true">15.3.4.</strong> Options</a></li><li class="chapter-item "><a href="../helpers/ws/read.html"><strong aria-hidden="true">15.3.5.</strong> Read</a></li><li class="chapter-item "><a href="../helpers/ws/meta.html"><strong aria-hidden="true">15.3.6.</strong> Meta</a></li><li class="chapter-item "><a href="../helpers/ws/write.html"><strong aria-hidden="true">15.3.7.</strong> Write</a></li></ol></li><li class="chapter-item "><a href="../helpers/headerapi/index.html"><strong aria-hidden="true">15.4.</strong> Headers API</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../helpers/headerapi/struct.html"><strong aria-hidden="true">15.4.1.</strong> Header struct</a></li><li class="chapter-item "><a href="../helpers/headerapi/get.html"><strong aria-hidden="true">15.4.2.</strong> Get a header</a></li><li class="chapter-item "><a href="../helpers/headerapi/iterate.html"><strong aria-hidden="true">15.4.3.</strong> Iterate over headers</a></li></ol></li></ol></li><li class="chapter-item "><a href="../examples/index.html"><strong aria-hidden="true">16.</strong> libcurl examples</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../examples/get.html"><strong aria-hidden="true">16.1.</strong> Get a simple HTTP page</a></li><li class="chapter-item "><a href="../examples/getinmem.html"><strong aria-hidden="true">16.2.</strong> Get a response into memory</a></li><li class="chapter-item "><a href="../examples/login.html"><strong aria-hidden="true">16.3.</strong> Submit a login form over HTTP</a></li><li class="chapter-item "><a href="../examples/ftplist.html"><strong aria-hidden="true">16.4.</strong> Get an FTP directory listing</a></li><li class="chapter-item "><a href="../examples/http-ul-nonblock.html"><strong aria-hidden="true">16.5.</strong> Non-blocking HTTP form-post</a></li></ol></li><li class="chapter-item "><a href="../bindings/index.html"><strong aria-hidden="true">17.</strong> libcurl bindings</a></li><li class="chapter-item "><a href="../internals/index.html"><strong aria-hidden="true">18.</strong> libcurl internals</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../internals/easy.html"><strong aria-hidden="true">18.1.</strong> Easy handles and connections</a></li><li class="chapter-item "><a href="../internals/multi.html"><strong aria-hidden="true">18.2.</strong> Everything is multi</a></li><li class="chapter-item "><a href="../internals/statemachines.html"><strong aria-hidden="true">18.3.</strong> State machines</a></li><li class="chapter-item "><a href="../internals/handler.html"><strong aria-hidden="true">18.4.</strong> Protocol handler</a></li><li class="chapter-item "><a href="../internals/backends.html"><strong aria-hidden="true">18.5.</strong> Backends</a></li><li class="chapter-item "><a href="../internals/caches.html"><strong aria-hidden="true">18.6.</strong> Caches and state</a></li><li class="chapter-item "><a href="../internals/timeouts.html"><strong aria-hidden="true">18.7.</strong> Timeouts</a></li><li class="chapter-item "><a href="../internals/windows-vs-unix.html"><strong aria-hidden="true">18.8.</strong> Windows vs Unix</a></li><li class="chapter-item "><a href="../internals/memory-debugging.html"><strong aria-hidden="true">18.9.</strong> Memory debugging</a></li><li class="chapter-item "><a href="../internals/content-encoding.html"><strong aria-hidden="true">18.10.</strong> Content Encoding</a></li><li class="chapter-item "><a href="../internals/structs.html"><strong aria-hidden="true">18.11.</strong> Structs</a></li><li class="chapter-item "><a href="../internals/resolving.html"><strong aria-hidden="true">18.12.</strong> Resolving hostnames</a></li><li class="chapter-item "><a href="../internals/tests/index.html"><strong aria-hidden="true">18.13.</strong> Tests</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../internals/tests/file-format.html"><strong aria-hidden="true">18.13.1.</strong> Test file format</a></li><li class="chapter-item "><a href="../internals/tests/build.html"><strong aria-hidden="true">18.13.2.</strong> Build tests</a></li><li class="chapter-item "><a href="../internals/tests/run.html"><strong aria-hidden="true">18.13.3.</strong> Run tests</a></li><li class="chapter-item "><a href="../internals/tests/debug.html"><strong aria-hidden="true">18.13.4.</strong> Debug builds</a></li><li class="chapter-item "><a href="../internals/tests/servers.html"><strong aria-hidden="true">18.13.5.</strong> Test servers</a></li><li class="chapter-item "><a href="../internals/tests/curl.html"><strong aria-hidden="true">18.13.6.</strong> curl tests</a></li><li class="chapter-item "><a href="../internals/tests/libcurl.html"><strong aria-hidden="true">18.13.7.</strong> libcurl tests</a></li><li class="chapter-item "><a href="../internals/tests/unit.html"><strong aria-hidden="true">18.13.8.</strong> Unit tests</a></li><li class="chapter-item "><a href="../internals/tests/valgrind.html"><strong aria-hidden="true">18.13.9.</strong> Valgrind</a></li><li class="chapter-item "><a href="../internals/tests/ci.html"><strong aria-hidden="true">18.13.10.</strong> Continuous Integration</a></li><li class="chapter-item "><a href="../internals/tests/autobuilds.html"><strong aria-hidden="true">18.13.11.</strong> Autobuilds</a></li><li class="chapter-item "><a href="../internals/tests/torture.html"><strong aria-hidden="true">18.13.12.</strong> Torture</a></li></ol></li></ol></li><li class="chapter-item "><a href="../bookindex.html"><strong aria-hidden="true">19.</strong> Index</a></li></ol> </div> <div id="sidebar-resize-handle" class="sidebar-resize-handle"> <div class="sidebar-resize-indicator"></div> </div> </nav>  <script> var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox'); sidebarScrollbox.addEventListener('click', function(e) { if (e.target.tagName === 'A') { sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop); } }, { passive: true }); var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll'); sessionStorage.removeItem('sidebar-scroll'); if (sidebarScrollTop) { // preserve sidebar scroll position when navigating via links within sidebar sidebarScrollbox.scrollTop = sidebarScrollTop; } else { // scroll sidebar to current active section when navigating via "next/previous chapter" buttons var activeSection = document.querySelector('#sidebar .active'); if (activeSection) { activeSection.scrollIntoView({ block: 'center' }); } } </script> <div id="page-wrapper" class="page-wrapper"> <div class="page"> <div id="menu-bar-hover-placeholder"></div> <div id="menu-bar" class="menu-bar sticky"> <div class="left-buttons"> <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar"> <i class="fa fa-bars"></i> </label> <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list"> <i class="fa fa-paint-brush"></i> </button> <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu"> <li role="none"><button role="menuitem" class="theme" id="light">Light</button></li> <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li> <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li> <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li> <li 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(Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> <i class="fa fa-search"></i> </button> </div> <h1 class="menu-title">everything curl</h1> <div class="right-buttons"> <a href="../print.html" title="Print this book" aria-label="Print this book"> <i id="print-button" class="fa fa-print"></i> </a> </div> </div> <div id="search-wrapper" class="hidden"> <form id="searchbar-outer" class="searchbar-outer"> <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header"> </form> <div id="searchresults-outer" class="searchresults-outer hidden"> <div id="searchresults-header" class="searchresults-header"></div> <ul id="searchresults"> </ul> </div> </div>  <script> document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible'); document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible'); Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) { link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1); }); </script> <div id="content" class="content"> <main> <h1 id="security"><a class="header" href="#security">Security</a></h1> <p>Security is a primary concern for us in the curl project. We take it seriously and we work hard on providing secure and safe implementations of all protocols and related code. As soon as we get knowledge about a security related problem or just a suspected problem, we deal with it and we attempt to provide a fix and security notice no later than in the next pending release.</p> <p>We use a responsible disclosure policy, meaning that we prefer to discuss and work on security fixes out of the public eye and we alert the vendors on the openwall.org list a few days before we announce the problem and fix to the world. This, in an attempt to shorten the time span the bad guys can take advantage of a problem until a fixed version has been deployed.</p> <h2 id="past-security-problems"><a class="header" href="#past-security-problems">Past security problems</a></h2> <p>During the years we have had our fair share of security related problems. We work hard on <a href="https://curl.se/docs/security.html">documenting every problem</a> thoroughly with all details listed and clearly stated to aid users. Users of curl should be able to figure out what problems their particular curl versions and use cases are vulnerable to.</p> <p>To help with this, we present <a href="https://curl.se/docs/vulnerabilities.html">this waterfall chart</a> showing how all vulnerabilities affect which curl versions and we have this complete list of all known security problems since the birth of this project.</p> <h2 id="backdoors-and-supply-chain-risks"><a class="header" href="#backdoors-and-supply-chain-risks">Backdoors and supply chain risks</a></h2> <p>With libcurl being installed and running in billions of installations all over the world and in countless different environments, we recognize that it is an ideal target for someone who wants a backdoor somewhere.</p> <p>A new or old maintainer might at any point propose a change that sounds innocent and well-meaning but has a disguised malicious intent.</p> <p>To mitigate such risks, we apply established procedures and techniques:</p> <ul> <li><strong>GitHub</strong>. The curl project uses <a href="https://github.com/curl/curl">https://github.com/curl/curl</a> as its main source code git repository since 2010. We rely on their hosting to secure access as per our configuration.</li> <li><strong>2FA required</strong>. We require all maintainers with push access to git to have two-factor authentication enabled, to reduce the risk that attackers can impersonate them and use their credentials to push source code changes. We rely on GitHub's 2FA setup.</li> <li><strong>Reviews</strong>. Every contribution that are proposed for inclusion in the project is reviewed by a maintainer. All changes are always done publicly in the open to allow all interested parties to participate. No invitation needed. All changes are also automatically checked, tested and scanned by numerous tools before accepted.</li> <li><strong>Readable code</strong>. We believe in readable code that follows our code style. Easy to read makes it easy to debug. If code is hard to read it should be improved until it gets easy to read. With easy to read code, smuggling malicious payloads or hiding nefarious functionality is excruciatingly hard.</li> <li><strong>Tests</strong>. We have a large test suite that is always growing and we do not accept changes that break existing tests and new functionality need to bring new tests for the new functionality. We run <em>several hundred thousands</em> tests on each proposed changed to make sure existing functionality remains. This includes fuzzers, static code analyzers, fault injectors and more.</li> <li><strong>No binary blobs</strong>. All files stored in version control, in the git repository is readable or is otherwise small and documented. There is no place anywhere for any hidden encrypted payload. We run a scanner on all files on every change to detect binary files and the few files that need to remain looking binary are manually vetted and verified against a checksum.</li> <li><strong>Reproducible builds</strong>. curl releases are shipped as tarballs that are hosted on the curl website (<a href="https://curl.se">https://curl.se</a>). We provide documentation, docker setups and configurations etc to allow anyone wanting to easily reproduce our release builds to generate identical images - proving that what we ship is only contents taken from the git repository plus other correct and properly generated contents.</li> <li><strong>Signed commits</strong>. Over 90% - not all - of recent commits were signed to help prove provenance. Signing commits is not yet a mandatory requirement for committers but we hope to gradually increase the share over time and make it mandatory soon.</li> <li><strong>Signed releases</strong>. Every release, every uploaded tarball, is signed by Daniel. This helps to prove that the files have not been tampered with since they were produced. We have opted to not sign them by multiple persons only because of the added complexity for the relatively small extra protection.</li> <li><strong>Signed tags</strong>. Every release is generated from the exact state of the git tree where a corresponding <em>signed</em> tag is set. The name of the release tag is the same as the release version.</li> <li><strong>Fix all vulnerabilities quickly</strong>. Whenever we receive a security vulnerability report, we create and ship a fix in the next pending release. Sometimes sooner than previously planned. Only in extremely rare cases does it take longer than a release cycle, but in the name of accuracy and correctness we do reserve the right to spend time on research to get it right. With every fixed security vulnerability we release a detailed description of the flaw including exact commit that introduced the problem, recommendations for users and more. Further, the security advisories get announced to the world.</li> </ul> </main> <nav class="nav-wrapper" aria-label="Page navigation">  <a rel="prev" href="../project/releases.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> <i class="fa fa-angle-left"></i> </a> <a rel="next prefetch" href="../project/trust.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> <div style="clear: both"></div> </nav> </div> </div> <nav class="nav-wide-wrapper" aria-label="Page navigation"> <a rel="prev" href="../project/releases.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> <i class="fa fa-angle-left"></i> </a> <a rel="next prefetch" href="../project/trust.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> </nav> </div> <script> window.playground_copyable = true; </script> <script src="../elasticlunr.min.js"></script> <script src="../mark.min.js"></script> <script src="../searcher.js"></script> <script src="../clipboard.min.js"></script> <script src="../highlight.js"></script> <script src="../book.js"></script>  </div> </body> </html>