From cea37260f3d63a4e497f0e5803d2a40c6f89dc0d Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Fri, 22 Jan 2021 20:01:19 +0000
Subject: treewide: reseed RNG in child processes

This prevents name conflicts leading to retries and slowdowns in
temporary file name generation.  No actual data corruption
resulted because all temporary files are opened with O_EXCL
anyways.

This may increase security for IMAP, NNTP, and HTTPS sessions
using TLS, but it's all public data anyways.
---
 lib/PublicInbox/Daemon.pm | 3 +++
 lib/PublicInbox/IPC.pm    | 6 +++++-
 lib/PublicInbox/Watch.pm  | 6 ++++++
 lib/PublicInbox/Xapcmd.pm | 4 +++-
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index f5543c85..b5f97d81 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -533,10 +533,13 @@ EOF
 		if ($n <= $want) {
 			PublicInbox::DS::block_signals() if !$sigfd;
 			for my $i ($n..$want) {
+				my $seed = rand(0xffffffff);
 				my $pid = fork;
 				if (!defined $pid) {
 					warn "failed to fork worker[$i]: $!\n";
 				} elsif ($pid == 0) {
+					srand($seed);
+					eval { Net::SSLeay::randomize() };
 					$set_user->() if $set_user;
 					return $p0; # run normal work code
 				} else {
diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm
index dbb87e4e..6efaff38 100644
--- a/lib/PublicInbox/IPC.pm
+++ b/lib/PublicInbox/IPC.pm
@@ -105,8 +105,10 @@ sub ipc_worker_spawn {
 	pipe(my ($r_res, $w_res)) or die "pipe: $!";
 	my $sigset = $oldset // PublicInbox::DS::block_signals();
 	$self->ipc_atfork_prepare;
-	defined(my $pid = fork) or die "fork: $!";
+	my $seed = rand(0xffffffff);
+	my $pid = fork // die "fork: $!";
 	if ($pid == 0) {
+		srand($seed);
 		eval { PublicInbox::DS->Reset };
 		delete @$self{qw(-wq_s1 -wq_workers -wq_ppid)};
 		$w_req = $r_res = undef;
@@ -286,8 +288,10 @@ sub wq_do { # always async
 
 sub _wq_worker_start ($$) {
 	my ($self, $oldset) = @_;
+	my $seed = rand(0xffffffff);
 	my $pid = fork // die "fork: $!";
 	if ($pid == 0) {
+		srand($seed);
 		eval { PublicInbox::DS->Reset };
 		delete @$self{qw(-wq_s1 -wq_workers -wq_ppid)};
 		$SIG{$_} = 'IGNORE' for (qw(PIPE TTOU TTIN));
diff --git a/lib/PublicInbox/Watch.pm b/lib/PublicInbox/Watch.pm
index 9a729140..1de5018d 100644
--- a/lib/PublicInbox/Watch.pm
+++ b/lib/PublicInbox/Watch.pm
@@ -625,8 +625,11 @@ sub imap_idle_fork ($$) {
 	my ($self, $url_intvl) = @_;
 	my ($url, $intvl) = @$url_intvl;
 	pipe(my ($r, $w)) or die "pipe: $!";
+	my $seed = rand(0xffffffff);
 	defined(my $pid = fork) or die "fork: $!";
 	if ($pid == 0) {
+		srand($seed);
+		eval { Net::SSLeay::randomize() };
 		close $r;
 		watch_atfork_child($self);
 		watch_imap_idle_1($self, $url, $intvl);
@@ -704,8 +707,11 @@ sub poll_fetch_fork ($) { # DS::add_timer callback
 	return if $self->{quit};
 	pipe(my ($r, $w)) or die "pipe: $!";
 	my $oldset = watch_atfork_parent($self);
+	my $seed = rand(0xffffffff);
 	my $pid = fork;
 	if (defined($pid) && $pid == 0) {
+		srand($seed);
+		eval { Net::SSLeay::randomize() };
 		close $r;
 		watch_atfork_child($self);
 		if ($urls->[0] =~ m!\Aimaps?://!i) {
diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 8de516ef..269aa99a 100644
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -89,8 +89,10 @@ sub commit_changes ($$$$) {
 
 sub cb_spawn {
 	my ($cb, $args, $opt) = @_; # $cb = cpdb() or compact()
-	defined(my $pid = fork) or die "fork: $!";
+	my $seed = rand(0xffffffff);
+	my $pid = fork // die "fork: $!";
 	return $pid if $pid > 0;
+	srand($seed);
 	$cb->($args, $opt);
 	POSIX::_exit(0);
 }
-- 
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