I go to a lot of concerts and I love to take pictures at the events. I literally have hundreds of photos of different celebrities. Can I publish them? Can I use them? Or upload them in social media? WITHOUT getting each musicians permission to use them?
And what about selling them to different publications?
There are a few sides of this - what above posters have said is correct for the most part. When you actually get photo passes, some of them come with contracts that you must fill out, sign and legally abide by. The sort of messed up part is that some concerts allow you to take a pro level camera in without a photo pass (though you will not be able to go in front of the barricade in this case), but with the right lens, you can still get some pretty spectacular shots and not be under the same contract that people with actual photo passes are. I've also had circumstances where a sponsor of the band has wanted to buy rights to commercially use my photos - and in that case there is a bit of an approval process between the management, the photographer and the sponsor.
I work for a few online publications and write articles/reviews covering shows. I find and email/call the band's press contact (or management if I can't find a particular press point) and let them know that I'd like to cover their show for whichever publication. They will then review the publication to make sure it's legitimate and respond yes or no. Before working for a publication, I found it very difficult to be approved for a photo pass, even after building a portfolio of local band photos. Most bands don't want just anyone coming in and taking high quality photos if they aren't giving the band any media attention/exposure.
Your country, the band, the venue, the bands contract with the venue, etc. all have bearing on how you can use the images if you did not get permission to take them and use them before hand.
Generally speaking, in the US, you can share the images. But once you sell them (either for commercial use or as art prints) things get trickier.*
*note - I am not a lawyer, and this should not be construed as legal advice.
And what about selling them to different publications?