Version(s) tested: 2.4.18, 2.4.41
Linux version: Ubuntu 16.04 (working), Ubuntu 20.04 (broken)
I can confirm that this bug appears to be a problem when using Apache 2.4.41 installed via package manager (apache2=2.4.41-4ubuntu3.1) on Ubuntu 20.04. This project is replacing an Ubuntu 16.04 host with Apache 2.4.18 using SMB 1.0. In an effort to isolate the issue, I tried the following:
- Changing SMB version from 3.1.1 to 2.0 and 1.0 - no change in behavior
- Building Apache 2.4.18 on Ubuntu 20.04 - no change in behavior
- Disabled all security tools in effect - no change in behavior
- Tried with EnableSendfile On - Some files started working, but not all
Disabling mmap with EnableMMAP Off is the only thing we have found that allows the service to work as expected.
To add some clarification to what the problem is for us, the files being served aren't just corrupted. What is happening for us is that the HTTP status line and the first few headers do not get sent. The remaining headers get prepended to the file being served. From a cursory check, it looks like the first 128 bytes of headers may be getting dropped altogether, though I've only spot checked this a couple of times. After the remaining headers are sent, the content is sent as well without a couple of newlines separating the header content from the file content.