Verify TLS certificate before downloading binaries

The --insecure flag to curl tells curl not to bother checking if the TLS
certificate presented by the server actually matches the hostname
requested, and actually is issued by a trusted CA chain.  This almost
entirely negates any benefit from using TLS in the first place.

This removes the --insecure flag to ensure we actually have a secure
connection to the intended hostname before downloading binaries.

Manually tested locally within a dev-shell; was able to download
binaries from https://cache.nixos.org without issue.

[Note: --insecure was only used for fetching NARs, whose integrity is
verified by Nix anyway using the hash from the .narinfo. But if we can
fetch the .narinfo without --insecure, we can also fetch the .nar, so
there is not much point to using --insecure. --Eelco]

1 files changed, 1 insertions, 2 deletions

diff --git a/scripts/download-using-manifests.pl.in b/scripts/download-using-manifests.pl.in
index 591cd6b43a3a..ffc49f8fffde 100755
--- a/scripts/download-using-manifests.pl.in
+++ b/scripts/download-using-manifests.pl.in
@@ -17,8 +17,7 @@ my $logFile = "$Nix::Config::logDir/downloads";
 # estimating the expected download size.
 my $fast = 1;
 
-# ‘--insecure’ is fine because Nix verifies the hash of the result.
-my $curl = "$Nix::Config::curl --fail --location --insecure";
+my $curl = "$Nix::Config::curl --fail --location";
 
 
 # Open the manifest cache and update it if necessary.