What would be the best way to verify a user uploaded file?

After a file开发者_高级运维 has been uploaded to the tmp folder, for example a pdf file, would php fileinfo mime check be enough to verify that the file is indeed a pdf file and is not infected?

How do you verify that a user uploaded file has no virus?

so that I could let users download it?

My scenario is this: A user uploads a pdf file, I then let another user read his pdf file.

php fileinfo mime check be enough to verify that the file is indeed a pdf file and is not infected

No. It will tell you if it looks like a PDF file, but do no virus checking.

How do you verify that a user uploaded file has no virus?

With a virus scanner. There are plenty of commercial and non-commercial packages out there.

A mime check does not guarantee anything, to be reasonably sure that a file has no virus, you will have to pass it through a virus scanner, like for example clam on linux.