The expectations of software robustness and security have increased a lot, and it's simply not realistic to achieve it while using unsafe tools making it much more difficult to write safe code. Writing something complex like an safe ext4 implementation is C is not very realistic.
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i.e. writing the entire thing with zero memory corruption bugs for an attacker to exploit either via an attacker controlled filesystem or an application. Drivers similarly have to be written treating the hardware and code using them as adversarial. Choice of tools is important.
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FS drivers do not belong in privileged contexts. The FS driver for an untrusted FS should be executing in a context where it can do nothing worse than store or retrieve wrong data.
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No, that's not what he means. He's saying that an external file system should have a sandboxed filesystem driver, so that exploiting a bug inside it doesn't immediately grant complete control over the entire system and at least requires privesc to escape (likely via the kernel).
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Try reading the overview in events.linuxfoundation.org/wp-content/upl. Finding a Linux kernel vulnerability is not hard. Literally hundreds of bugs are found by syszkiller every month and many are not fixed. Most are memory corruption. There are simply too many to even fix all discovered bugs.
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yes, we don't need to debate the question "can people write memory safe code in C" the answer is overwhelmingly obvious to almost all of us
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CVE assignments are a tiny subset of fixed security bugs. GNU grep does not seek CVE assignments for each security bug that they fix. Only external security researchers generally have an interest in seeking CVE assignments and it's mostly for self-promotion. It's the exception.
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Try reading what I linked to you including the official Linux kernel documentation and the post by Greg KH where they explain that they don't seek CVE assignments. Greg KH has explained many times that most security bugs do not receive CVEs so backporting only those is awful.
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You can search commits for buffer overflows, use-after-frees, etc. and find tons of clear security vulnerabilities that never received a CVE. I mean really you can just grep through most projects for malloc with arithmetic on the same line and find lots of obvious heap overflows.
malloc(n * sizeof(T)) or realloc(p, n* sizeof(T)) where n is an attacker controlled value is ridiculously obvious low-hanging fruit that's somehow present in tons of projects. It's usually not one line but there are enough of those that it's easy to find cases to check with grep.
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