smtp: verify the certificate of the SMTP server for STARTTLS/SMTPS
Before this patch, the certificate of the SMTP server for STARTTLS or
SMTPS isn't verified.
This may cause man-in-the-middle security problem (stealing
authentication information), even though SMTP channel itself is
encrypted by SSL.
When "[smtp] tls" is configured as "smtps" or "starttls", this patch:
- uses classes introduced by preceding patches instead of "SMTP" or
"SMTP_SSL" of smtplib, and
- verifies the certificate of the SMTP server, if "[smtp]
verifycert" is configured as other than False
"[smtp] verifycert" can be configured in 3 levels:
- "strict":
This verifies peer certificate, and aborts if:
- peer certification is not valid, or
- no configuration in "[hostfingerprints]" and "[web] cacerts"
This is default value of "[smtp] verifycert" for security.
- "loose":
This verifies peer certificate, and aborts if peer certification is
not valid.
This just shows warning message ("certificate not verified"), if
there is no configuration in "[hostfingerprints]" and "[web]
cacerts".
This is as same as verification for HTTPS connection.
- False(no verification):
Peer certificate is not verified.
This is as same as the behavior before this patch series.
"hg email --insecure" uses "loose" level, and ignores "[web] cacerts"
as same as push/pull/etc... with --insecure.
Ignoring "[web] cacerts" configuration for "hg email --insecure" is
already done in "dispatch._dispatch()" by looking "insecure" up in the
table of command options.
DOCUMENT_ROOT="/var/www/hg"; export DOCUMENT_ROOT
GATEWAY_INTERFACE="CGI/1.1"; export GATEWAY_INTERFACE
HTTP_ACCEPT="text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"; export HTTP_ACCEPT
HTTP_ACCEPT_CHARSET="ISO-8859-1,utf-8;q=0.7,*;q=0.7"; export HTTP_ACCEPT_CHARSET
HTTP_ACCEPT_ENCODING="gzip,deflate"; export HTTP_ACCEPT_ENCODING
HTTP_ACCEPT_LANGUAGE="en-us,en;q=0.5"; export HTTP_ACCEPT_LANGUAGE
HTTP_CACHE_CONTROL="max-age=0"; export HTTP_CACHE_CONTROL
HTTP_CONNECTION="keep-alive"; export HTTP_CONNECTION
HTTP_HOST="hg.omnifarious.org"; export HTTP_HOST
HTTP_KEEP_ALIVE="300"; export HTTP_KEEP_ALIVE
HTTP_USER_AGENT="Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8.0.4) Gecko/20060608 Ubuntu/dapper-security Firefox/1.5.0.4"; export HTTP_USER_AGENT
PATH_INFO="/"; export PATH_INFO
PATH_TRANSLATED="/var/www/hg/index.html"; export PATH_TRANSLATED
QUERY_STRING=""; export QUERY_STRING
REMOTE_ADDR="127.0.0.2"; export REMOTE_ADDR
REMOTE_PORT="44703"; export REMOTE_PORT
REQUEST_METHOD="GET"; export REQUEST_METHOD
REQUEST_URI="/test/"; export REQUEST_URI
SCRIPT_FILENAME="/home/hopper/hg_public/test.cgi"; export SCRIPT_FILENAME
SCRIPT_NAME="/test"; export SCRIPT_NAME
SCRIPT_URI="http://hg.omnifarious.org/test/"; export SCRIPT_URI
SCRIPT_URL="/test/"; export SCRIPT_URL
SERVER_ADDR="127.0.0.1"; export SERVER_ADDR
SERVER_ADMIN="eric@localhost"; export SERVER_ADMIN
SERVER_NAME="hg.omnifarious.org"; export SERVER_NAME
SERVER_PORT="80"; export SERVER_PORT
SERVER_PROTOCOL="HTTP/1.1"; export SERVER_PROTOCOL
SERVER_SIGNATURE="<address>Apache/2.0.53 (Fedora) Server at hg.omnifarious.org Port 80</address>"; export SERVER_SIGNATURE
SERVER_SOFTWARE="Apache/2.0.53 (Fedora)"; export SERVER_SOFTWARE