Automated, reproducible, transparent, Windows builds for curl, nghttp2, brotli, libssh2 and OpenSSL 1.1

• SECURITY NOTICE: It is strongly recommended to upgrade to curl 7.65.1_2 and OpenSSL 1.1.1c_2, released on 2019-06-20, or newer. Previous releases were discovered to have a code injection (and potential privilege escalation) vulnerability triggered via OpenSSL's build configuration defaults when using certain Windows compilers, including MinGW. The issue has been fixed by applying a local OpenSSL patch along with the required build configuration change.
  Further information: CVE-2019-5443
• Packaging aims to follow popular binary releases found on the internet.
• Both x64 and x86 packages are built using the same process.
• Binary packages are downloadable in .zip and .tar.xz formats.
  .xz files and the resulting .tar archive can also be extracted using 7-Zip on Windows.
• Standalone curl.exe (only msvcrt.dll is required).
• curl/libcurl are built with HTTP/2 support enabled.
• curl/libcurl features enabled by default:
  dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp
AsynchDNS HTTP2 HTTPS-proxy IDN IPv6 Kerberos Largefile MultiSSL NTLM SPNEGO SSL SSPI TLS-SRP brotli libz
• The build process is fully transparent by using publicly available open source code, C compiler, build scripts and running the build in public, with open, auditable build logs.
• C compiler toolchain is latest MinGW-w64 (non-multilib, x64 and x86) either via Homebrew (on macOS), APT (on Debian via Docker) or MSYS2 (on Windows). C compiler is GCC or LLVM/Clang for projects supporting it.
• Binaries are cross-built and published from Linux (via AppVeyor CI), using LLVM/Clang for curl, libssh2, nghttp2, c-ares, brotli and zlib, and GCC for OpenSSL.
  Exact OS image used for the builds is debian:testing (a reproducible image) via Docker.
• Binaries are built with supported hardening options enabled.
• Binaries are using DWARF in x86 and SEH in x64 builds.
• Components are verified using SHA-256 hashes and also GPG signatures where available.
• Generated binaries are reproducible, meaning they will have the same hash given the same input sources and C compiler.
• Because the build environment is updated before each build, subsequent builds may use different versions/builds of the compiler toolchain. This may result in different generated binaries given otherwise unchanged source code and configuration, sometimes thus breaking reproducibility. This trade-off was decided to be tolerable for more ideal binaries and allowing this project to automatically benefit from continuous C compiler updates.
• Patching policy: No locally maintained patches. Patches are only applied locally if already merged upstream or — in case it's necessary for a successful build — had them submitted upstream with fair confidence of getting accepted.
• curl/libcurl are built in MultiSSL mode, with both OpenSSL and WinSSL available as SSL backends.
• Optional support for C-ares.
• Generated binaries are uploaded to VirusTotal.
• If you need a download with a stable checksum, link to the penultimate version (or the revisioned binaries on the official download page). Only the current latest versions are kept updated with newer dependencies.
• To verify the correct checksum for the latest build, you can look up the correct ones in the build log as they are generated. Watch for master branch job Image: Ubuntu, log lines starting with SHA256( or SHA512(: https://ci.appveyor.com/project/curlorg/curl-for-win/branch/master
• The build process is multi-platform and able to cross-build Windows executables from *nix hosts (Linux and macOS tested.)
• Packages created across different host platforms won't currently have identical hashes. The reason for this is the slightly different build options and versions of the mingw-w64 and binutils tools.
• Binaries distributed via Bintray are GPG signed with Bintray's key pair: 8756 C4F7 65C9 AC3C B6B8 5D62 379C E192 D401 AB61
• Code signing is implemented and enabled with a self-signed certificate. The signature intentionally omits a trusted timestamp to retain reproducibility. Signing is done using a custom patched osslsigncode build to enforce a stable non-trusted timestamp for reproducibility.

Binary package downloads

• Official page:
  https://curl.haxx.se/windows/
• Bintray:
  • curl
  • OpenSSL
  • libssh2
  • nghttp2
  • brotli
  • zlib

Live build logs

• https://ci.appveyor.com/project/curlorg/curl-for-win/branch/master (Image: Ubuntu) (for published binaries)
• https://ci.appveyor.com/project/vszakats/curl-for-win/branch/master (historical)
• https://travis-ci.org/curl/curl-for-win

Guarantees and Liability

THIS SOFTWARE (INCLUDING RESULTING BINARIES) IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Information in this document is subject to change without notice and does not represent or imply any future commitment by the participants of the project.

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This document © 2014–present Viktor Szakats