wget: add a big explanation what TLS code implements and what does not

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/networking/wget.c b/networking/wget.c
index 90eedaf7a..252f94dc6 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -58,6 +58,39 @@
 //config:         On NOMMU machines, ssl_helper applet should be available
 //config:         in the $PATH for this to work. Make sure to select that applet.
 //config:
+//config:         Note: currently, TLS code only makes TLS I/O work, it
+//config:         does *not* check that the peer is who it claims to be, etc.
+//config:         IOW: it uses peer-supplied public keys to establish encryption
+//config:         and signing keys, then encrypts and signs outgoing data and
+//config:         decrypts incoming data.
+//config:         It does not check signature hashes on the incoming data:
+//config:         this means that attackers manipulating TCP packets can
+//config:         send altered data and we unknowingly receive garbage.
+//config:         (This check might be relatively easy to add).
+//config:         It does not check public key's certificate:
+//config:         this means that the peer may be an attacker impersonating
+//config:         the server we think we are talking to.
+//config:
+//config:         If you think this is unacceptable, consider this. As more and more
+//config:         servers switch to HTTPS-only operation, without such "crippled"
+//config:         TLS code it is *impossible* to simply download a kernel source
+//config:         from kernel.org. Which can in real world translate into
+//config:         "my small automatic tooling to build cross-compilers from sources
+//config:         no longer works, I need to additionally keep a local copy
+//config:         of ~4 megabyte source tarball of a SSL library and ~2 megabyte
+//config:         source of wget, need to compile and built both before I can
+//config:         download anything. All this despite the fact that the build
+//config:         is done in a QEMU sandbox on a machine with absolutely nothing
+//config:         worth stealing, so I don't care if someone would go to a lot
+//config:         of trouble to intercept my HTTPS download to send me an altered
+//config:         kernel tarball".
+//config:
+//config:         If you still think this is unacceptable, send patches.
+//config:
+//config:         If you still think this is unacceptable, do not want to send
+//config:         patches, but do want to waste bandwidth expaining how wrong
+//config:         it is, you will be ignored.
+//config:
 //config:config FEATURE_WGET_OPENSSL
 //config:       bool "Try to connect to HTTPS using openssl"
 //config:       default y