This commit makes some of the TLS options that are used for
impersonation configurable via libcurl options and command line flags to
curl-impersonate. The goal is to give more flexibility in configuring
the TLS extensions instead of hardcoding everything into the binary.
This will enable using the same binary for impersonating different
browsers (e.g. Safari).
The following options are now present:
* CURLOPT_SSL_EC_CURVES and the '--curves' flag are now usable. These
were present in the upstream curl but only for OpenSSL builds. This
commit also enables them for BoringSSL. They configure TLS extension
'supported_groups' (no. 10).
* CURLOPT_SSL_ENABLE_NPN and the '--no-npn' flags are usable. These were
present in the upstream curl but were disabled in a previous commit by
commenting out the relevant code (as Chrome disables NPN). They now work
and the wrapper scripts use the '--no-npn' flag.
* CURLOPT_SSL_ENABLE_ALPS and the '--alps' flag were added. These
control the ALPS TLS extension that Chrome uses.
* CURLOPT_SSL_SIG_HASH_ALGS and the '--signature-hashes' option were
added. These control the clien't list of supported signature & hash
algorithms, i.e. TLS extension 'signature_algorithms' (no. 13).
Patch generated from e8cd43c8eb
Add curl_easy_impersonate() API function that sets the needed options
on the curl 'easy' handle. It sets the various TLS options needed for
impersonation and the HTTP headers that the browser sends by default.
In addition, libcurl will check for the environment variable
CURL_IMPERSONATE when curl_easy_init() is called, and if it exists it
will call curl_easy_impersonate() internally. This theoretically allows
replacing an existing libcurl by setting the LD_LIBRARY_PATH and
CURL_IMPERSONATE env vars, without having to recompile the app.
Consolidate all of curl's patch files into a single file (one for each
browser). The modified curl source code is now maintained in Git (at
https://github.com/lwthiker/curl) and it is easier to just
generate the needed patch with 'git --diff'.
