[pve-devel] [PATCH v3 http-server 2/3] fix multipart upload: ignore additional headers

[Matthias Heiserer <m.heiserer@proxmox.com>]

Reported in the forum: https://forum.proxmox.com/threads/image-upload-fails-after-upgrading-from-7-1-to-7-3.119051/#post-516517

When additional headers existed in the request body, the upload failed.
With this patch, all additional headers get ignored.

Example: The following upload would fail because no
headers were expected after Content-Disposition.

```
--EPIHyQJFC5ftgoXHMe8-Jc6E7FqA4oMb0QBfOTz
Content-Disposition: form-data; name="content"
Content-Type: text/plain; charset=ISO-8859-1

iso
```
would fail. These headers now also get ignored, as we don't use them.

Also, upload now works when the Content-Disposition header isn't the first, i.e.
```
--XVH95dt1-A3J8mWiLCmHCW4roSC7-gBntjATBy--
Content-Type: text/plain; charset=ISO-8859-1
Content-Disposition: form-data; name="content"
```

Fixed upload was tested using
* Curl
* GUI
* Apache HttpClient 5

Signed-off-by: Matthias Heiserer <m.heiserer@proxmox.com>
---

Changes from v2:
None

Changes from v1:
* wait for delimiter before handling data, as reported in forum
* squash ignore order of headers patch

 src/PVE/APIServer/AnyEvent.pm | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/PVE/APIServer/AnyEvent.pm b/src/PVE/APIServer/AnyEvent.pm
index 545c122..2f8718f 100644
--- a/src/PVE/APIServer/AnyEvent.pm
+++ b/src/PVE/APIServer/AnyEvent.pm
@@ -1201,11 +1201,19 @@ sub file_upload_multipart {
 	    $rstate->{phase} = 1;
 	}
 
+	my $remove_until_data = sub {
+	    my ($hdl) = @_;
+	    # remove any remaining multipart "headers" like Content-Type
+	    $hdl->{rbuf} =~ s/^.*?${newline_re}{2}//s;
+	};
+
 	my $extract_form_disposition = sub {
 	    my ($name) = @_;
-	    if ($hdl->{rbuf} =~ s/^${delim_re}Content-Disposition: (.*?); name="$name"(.*?)($delim_re)/$3/s) {
+	    if ($hdl->{rbuf} =~ s/^${delim_re}.*?Content-Disposition: (.*?); name="$name"(.*?${delim_re})/$2/s) {
 		assert_form_disposition($1);
-		$rstate->{params}->{$name} = trim($2);
+		$remove_until_data->($hdl);
+		$hdl->{rbuf} =~ s/^(.*?)(${delim_re})/$2/s;
+		$rstate->{params}->{$name} = trim($1);
 	    }
 	};
 
-- 
2.30.2