michael/webmin
1
0
Fork 0
mirror of https://github.com/webmin/webmin.git synced 2026-05-14 18:50:29 +01:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

Merge pull request #2692 from swelljoe/session-dbm
Some checks failed
webmin.dev: webmin/webmin / build (push) Has been cancelled
Details

Browse Source 
Prefer SHA over MD5 or crypt for session hash, other minor session tweaks
This commit is contained in:
Jamie Cameron
2026-05-10 22:03:47 -07:00
committed by GitHub
parent ce1ab74c6f 7aeb5e4dd7
commit 2c8ff4ba15
1 changed files with 102 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

116
miniserv.pl
View File

@@ -104,6 +104,14 @@ if (&unix_crypt_supports_sha512()) {
push(@startup_msg, "Using SHA512 via crypt() function");
}
# Check if Digest::SHA with hmac_sha256_hex is available, for keying
# the session-ID lookup table.
eval "use Digest::SHA qw(hmac_sha256_hex); hmac_sha256_hex('x', 'y');";
if (!$@) {
$use_hmac_sha256 = 1;
push(@startup_msg, "Using HMAC-SHA256 for session ID hashing");
}
# Get miniserv's perl path and location
$miniserv_path = $0;
open(SOURCE, $miniserv_path);
@@ -605,17 +613,7 @@ if ($config{'logclear'}) {
# Setup the logout time dbm if needed
if ($config{'session'}) {
eval "use SDBM_File";
dbmopen(%sessiondb, $config{'sessiondb'}, 0700);
eval "\$sessiondb{'1111111111'} = 'foo bar';";
if ($@) {
dbmclose(%sessiondb);
eval "use NDBM_File";
dbmopen(%sessiondb, $config{'sessiondb'}, 0700);
}
else {
delete($sessiondb{'1111111111'});
}
&open_session_db();
}
# Run the main loop
@@ -4999,7 +4997,7 @@ print DEBUG "in reload_config_file\n";
&parse_websockets_config();
if ($config{'session'}) {
dbmclose(%sessiondb);
dbmopen(%sessiondb, $config{'sessiondb'}, 0700);
&open_session_db();
}
print DEBUG "done reload_config_file\n";
}
@@ -5083,6 +5081,12 @@ my $var_dir = $1;
if (!$config{'sessiondb'}) {
$config{'sessiondb'} = "$var_dir/sessiondb";
}
if ($config{'session'}) {
if (!$config{'session_keyfile'}) {
$config{'session_keyfile'} = "$var_dir/session.key";
}
&load_session_secret();
}
if (!$config{'errorlog'}) {
$config{'logfile'} =~ /^(.*)\/[^\/]+$/;
$config{'errorlog'} = "$1/miniserv.error";
@@ -6525,12 +6529,19 @@ return -1; # This should never be reached
}
# hash_session_id(sid)
# Returns an MD5 or Unix-crypted session ID
# Returns a keyed hash of a session ID, used as the lookup key in the
# session DBM. HMAC-SHA256 with a per-install secret is preferred; the
# legacy MD5 / Unix crypt paths remain only as fallbacks for systems that
# lack Digest::SHA.
sub hash_session_id
{
local ($sid) = @_;
if (!$hash_session_id_cache{$sid}) {
if ($use_md5) {
if ($use_hmac_sha256 && $session_hmac_key) {
$hash_session_id_cache{$sid} =
Digest::SHA::hmac_sha256_hex($sid, $session_hmac_key);
}
elsif ($use_md5) {
# Take MD5 hash
$hash_session_id_cache{$sid} = &encrypt_md5($sid);
}
@@ -6542,6 +6553,83 @@ if (!$hash_session_id_cache{$sid}) {
return $hash_session_id_cache{$sid};
}
# load_session_secret()
# Reads a per-install HMAC key from $config{'session_keyfile'}, or generates
# a new 32-byte key from /dev/urandom and writes it with mode 0600 if the
# file is missing. Sets $session_hmac_key. Idempotent across config reloads.
sub load_session_secret
{
my $kf = $config{'session_keyfile'};
return if (!$kf);
my $oldumask = umask(0077);
if (-r $kf) {
chmod(0600, $kf);
if (open(my $fh, "<", $kf)) {
binmode($fh);
local $/;
$session_hmac_key = <$fh>;
close($fh);
}
}
if (!$session_hmac_key || length($session_hmac_key) < 16) {
my $key;
if (open(my $rh, "<", "/dev/urandom")) {
binmode($rh);
read($rh, $key, 32);
close($rh);
}
if (!$key || length($key) < 32) {
# /dev/urandom unusable; fall back to a hashed mix of
# Perl's rand() and the PID/time. Weaker, but the file
# still ends up 0600 and is per-install.
my $mix = '';
$mix .= pack("N", int(rand(0xffffffff))) for (1..8);
$mix .= pack("NN", $$, time());
if ($use_hmac_sha256) {
$key = Digest::SHA::sha256($mix);
}
else {
$key = $mix;
}
}
if (open(my $wh, ">", $kf)) {
binmode($wh);
chmod(0600, $kf);
print $wh $key;
close($wh);
$session_hmac_key = $key;
}
else {
&log_error("Failed to write session key file $kf : $!");
}
}
umask($oldumask);
}
# open_session_db()
# Opens the session DBM with a tight umask, then forces 0600 on the
# resulting on-disk files so pre-existing loose perms from older installs
# are corrected. Tries SDBM first, falling back to NDBM.
sub open_session_db
{
my $oldumask = umask(0077);
eval "use SDBM_File";
dbmopen(%sessiondb, $config{'sessiondb'}, 0600);
eval "\$sessiondb{'1111111111'} = 'foo bar';";
if ($@) {
dbmclose(%sessiondb);
eval "use NDBM_File";
dbmopen(%sessiondb, $config{'sessiondb'}, 0600);
}
else {
delete($sessiondb{'1111111111'});
}
foreach my $f (glob("$config{'sessiondb'}*")) {
chmod(0600, $f);
}
umask($oldumask);
}
# encrypt_md5(string, [salt])
# Returns a string encrypted in MD5 format
sub encrypt_md5