You'd know better than I would, though I'm not inclined to apologize. I will use more mildly negative language henceforth, however.
My problems with Grsecurity are, in order of importance:
- This whole licensing thing. I like the GPL. I publish much of my software under the GPL. I want the GPL to be a real thing that we all respect and abide by. When someone breaks that social contract, we all lose.
- The lack of effort to work with the rest of the kernel community. They've got this huge stack of patches (and it is huge), they're selling it to a bunch of folks (some of whom probably know enough to be making security decisions, many of whom probably don't), and yet they don't really seem interested in being a member of the OSS community.
- There's a recurring theme (even before now, I've heard this argument) of people asserting that someone attacked their server, and, because they had grsec, it crashed instead of allowing the attacker to exploit the system. As though that's not a successful attack in and of itself. The quality of grsecurity code has been called into question by more than one kernel dev, including Linus.
- There's some misleading marketing going on somewhere. I happen to work in the industry sort of parallel to grsecurity. We have a handful of the same customers, there's some overlap in the systems we see and the ones they exist on. For whatever reason, our users who have grsecurity on their systems are the most poorly informed about how the security features of a Linux system fit together (and they think all of them come from grsecurity, even though usually it's none of the ones we're talking about or helping them with). I don't know if grsecurity folks are misleading their customers, or people are just filling in the blanks with where security comes from (obviously it's the security product they paid money for, rather than the kernel itself which was free and thus obviously worthless). It's like the Fox News of kernel patches, somehow messing with it makes people less knowledgeable about the security of their systems.
It's a personal pet peeve, I guess. But, there are, as I said, good ideas in grsecurity. I wish they'd go through the usual process of getting things into the kernel. As it is, they've got a cool research kernel that's unfortunately been pushed into production on some of the most dangerous systems out there (shared hosting and multi-tenancy systems that have barely trusted users and frequently run poorly maintained web apps that often expose the system to untrusted code).
I'm rambling a bit here, but my point is, I won't call it snake oil anymore, but I'm probably not gonna shower it with praise, either. The folks building it are clearly very smart. I really don't mean to denigrate their skills, their experience, or even the software they've built. I just wish they worked with the kernel community more, and I wish whoever is spreading around myths about kernel security and how grsec interacts with it would stop doing so.