[pmg-devel] [PATCH pmg-api v3 2/5] utils: content-type: don't fallback to header information for magic

[Stoiko Ivanov]

file-type detection based on content/magic is the single piece of
information not determined by the headers of the e-mail, and thus not
directly controlled by the sender.

this patch removes the fallback to the content-type header mime-type
in case magic_mime_type_for_file does not detect the type.

Reported-by: Friedrich Weber <f.weber at proxmox.com>
Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
---
 src/PMG/RuleDB/ArchiveFilter.pm     |  2 +-
 src/PMG/RuleDB/ContentTypeFilter.pm |  2 +-
 src/PMG/Utils.pm                    | 12 ++++--------
 3 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/src/PMG/RuleDB/ArchiveFilter.pm b/src/PMG/RuleDB/ArchiveFilter.pm
index 3d9890c..d7f6399 100644
--- a/src/PMG/RuleDB/ArchiveFilter.pm
+++ b/src/PMG/RuleDB/ArchiveFilter.pm
@@ -59,7 +59,7 @@ sub parse_entity {
     if (my $id = $entity->head->mime_attr ('x-proxmox-tmp-aid')) {
 	chomp $id;
 
-	my $header_ct = $entity->head->mime_attr ('content-type');
+	my $header_ct = $entity->{PMX_header_ct};
 
 	my $magic_ct = $entity->{PMX_magic_ct};
 
diff --git a/src/PMG/RuleDB/ContentTypeFilter.pm b/src/PMG/RuleDB/ContentTypeFilter.pm
index 0199311..fb45e95 100644
--- a/src/PMG/RuleDB/ContentTypeFilter.pm
+++ b/src/PMG/RuleDB/ContentTypeFilter.pm
@@ -72,7 +72,7 @@ sub parse_entity {
     if (my $id = $entity->head->mime_attr ('x-proxmox-tmp-aid')) {
 	chomp $id;
 
-	my $header_ct = $entity->head->mime_attr ('content-type');
+	my $header_ct = $entity->{PMX_header_ct};
 
 	my $magic_ct = $entity->{PMX_magic_ct};
 
diff --git a/src/PMG/Utils.pm b/src/PMG/Utils.pm
index 0b8945f..b2a75fb 100644
--- a/src/PMG/Utils.pm
+++ b/src/PMG/Utils.pm
@@ -598,7 +598,7 @@ sub magic_mime_type_for_file {
     my $bufsize = Xdgmime::xdg_mime_get_max_buffer_extents();
     die "got strange value for max_buffer_extents" if $bufsize > 4096*10;
 
-    my $ct = "application/octet-stream";
+    my $ct;
 
     my $fh = IO::File->new("<$filename") ||
 	die "unable to open file '$filename' - $!";
@@ -611,6 +611,7 @@ sub magic_mime_type_for_file {
 
     die "unable to read file '$filename' - $!" if ($len < 0);
 
+    $ct ||= "application/octet-stream";
     return $ct;
 }
 
@@ -619,14 +620,9 @@ sub add_ct_marks {
 
     if (my $path = $entity->{PMX_decoded_path}) {
 
-	# set a reasonable default if magic does not give a result
-	$entity->{PMX_magic_ct} = $entity->head->mime_attr('content-type');
+	$entity->{PMX_header_ct} = $entity->head->mime_attr('content-type');
 
-	if (my $ct = magic_mime_type_for_file($path)) {
-	    if ($ct ne 'application/octet-stream' || !$entity->{PMX_magic_ct}) {
-		$entity->{PMX_magic_ct} = $ct;
-	    }
-	}
+	$entity->{PMX_magic_ct} = magic_mime_type_for_file($path);
 
 	my $filename = $entity->head->recommended_filename;
 	$filename = basename($path) if !defined($filename) || $filename eq '';
-- 
2.39.5