Fix file operations in c_rehash.

CVE-2022-2068

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>

1 files changed, 52 insertions, 54 deletions

diff --git a/tools/c_rehash.in b/tools/c_rehash.in
index 081b34aec8..2f735d68c9 100644
--- a/tools/c_rehash.in
+++ b/tools/c_rehash.in
@@ -104,18 +104,41 @@ foreach (@dirlist) {
 }
 exit($errorcount);
 
+sub copy_file {
+    my ($src_fname, $dst_fname) = @_;
+
+    if (open(my $in, "<", $src_fname)) {
+        if (open(my $out, ">", $dst_fname)) {
+            print $out $_ while (<$in>);
+            close $out;
+        } else {
+            warn "Cannot open $dst_fname for write, $!";
+        }
+        close $in;
+    } else {
+        warn "Cannot open $src_fname for read, $!";
+    }
+}
+
 sub hash_dir {
+    my $dir = shift;
     my %hashlist;
-    print "Doing $_[0]\n";
-    chdir $_[0];
-    opendir(DIR, ".");
+
+    print "Doing $dir\n";
+
+    if (!chdir $dir) {
+        print STDERR "WARNING: Cannot chdir to '$dir', $!\n";
+        return;
+    }
+
+    opendir(DIR, ".") || print STDERR "WARNING: Cannot opendir '.', $!\n";
     my @flist = sort readdir(DIR);
     closedir DIR;
     if ( $removelinks ) {
         # Delete any existing symbolic links
         foreach (grep {/^[\da-f]+\.r{0,1}\d+$/} @flist) {
             if (-l $_) {
-                print "unlink $_" if $verbose;
+                print "unlink $_\n" if $verbose;
                 unlink $_ || warn "Can't unlink $_, $!\n";
             }
         }
@@ -130,13 +153,16 @@ sub hash_dir {
         link_hash_cert($fname) if ($cert);
         link_hash_crl($fname) if ($crl);
     }
+
+    chdir $pwd;
 }
 
 sub check_file {
     my ($is_cert, $is_crl) = (0,0);
     my $fname = $_[0];
-    open IN, $fname;
-    while(<IN>) {
+
+    open(my $in, "<", $fname);
+    while(<$in>) {
         if (/^-----BEGIN (.*)-----/) {
             my $hdr = $1;
             if ($hdr =~ /^(X509 |TRUSTED |)CERTIFICATE$/) {
@@ -148,7 +174,7 @@ sub check_file {
             }
         }
     }
-    close IN;
+    close $in;
     return ($is_cert, $is_crl);
 }
 
@@ -177,51 +203,22 @@ sub compute_hash {
 # certificate fingerprints
 
 sub link_hash_cert {
-    my $fname = $_[0];
-    my ($hash, $fprint) = compute_hash($openssl, "x509", $x509hash,
-                                       "-fingerprint", "-noout",
-                                       "-in", $fname);
-    chomp $hash;
-    chomp $fprint;
-    return if !$hash;
-    $fprint =~ s/^.*=//;
-    $fprint =~ tr/://d;
-    my $suffix = 0;
-    # Search for an unused hash filename
-    while(exists $hashlist{"$hash.$suffix"}) {
-        # Hash matches: if fingerprint matches its a duplicate cert
-        if ($hashlist{"$hash.$suffix"} eq $fprint) {
-            print STDERR "WARNING: Skipping duplicate certificate $fname\n";
-            return;
-        }
-        $suffix++;
-    }
-    $hash .= ".$suffix";
-    if ($symlink_exists) {
-        print "link $fname -> $hash\n" if $verbose;
-        symlink $fname, $hash || warn "Can't symlink, $!";
-    } else {
-        print "copy $fname -> $hash\n" if $verbose;
-        if (open($in, "<", $fname)) {
-            if (open($out,">", $hash)) {
-                print $out $_ while (<$in>);
-                close $out;
-            } else {
-                warn "can't open $hash for write, $!";
-            }
-            close $in;
-        } else {
-            warn "can't open $fname for read, $!";
-        }
-    }
-    $hashlist{$hash} = $fprint;
+    link_hash($_[0], 'cert');
 }
 
 # Same as above except for a CRL. CRL links are of the form <hash>.r<n>
 
 sub link_hash_crl {
-    my $fname = $_[0];
-    my ($hash, $fprint) = compute_hash($openssl, "crl", $crlhash,
+    link_hash($_[0], 'crl');
+}
+
+sub link_hash {
+    my ($fname, $type) = @_;
+    my $is_cert = $type eq 'cert';
+
+    my ($hash, $fprint) = compute_hash($openssl,
+                                       $is_cert ? "x509" : "crl",
+                                       $is_cert ? $x509hash : $crlhash,
                                        "-fingerprint", "-noout",
                                        "-in", $fname);
     chomp $hash;
@@ -231,22 +228,23 @@ sub link_hash_crl {
     $fprint =~ tr/://d;
     my $suffix = 0;
     # Search for an unused hash filename
-    while(exists $hashlist{"$hash.r$suffix"}) {
+    my $crlmark = $is_cert ? "" : "r";
+    while(exists $hashlist{"$hash.$crlmark$suffix"}) {
         # Hash matches: if fingerprint matches its a duplicate cert
-        if ($hashlist{"$hash.r$suffix"} eq $fprint) {
-            print STDERR "WARNING: Skipping duplicate CRL $fname\n";
+        if ($hashlist{"$hash.$crlmark$suffix"} eq $fprint) {
+            my $what = $is_cert ? 'certificate' : 'CRL';
+            print STDERR "WARNING: Skipping duplicate $what $fname\n";
             return;
         }
         $suffix++;
     }
-    $hash .= ".r$suffix";
+    $hash .= ".$crlmark$suffix";
     if ($symlink_exists) {
         print "link $fname -> $hash\n" if $verbose;
         symlink $fname, $hash || warn "Can't symlink, $!";
     } else {
-        print "cp $fname -> $hash\n" if $verbose;
-        system ("cp", $fname, $hash);
-        warn "Can't copy, $!" if ($? >> 8) != 0;
+        print "copy $fname -> $hash\n" if $verbose;
+        copy_file($fname, $hash);
     }
     $hashlist{$hash} = $fprint;
 }