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Null pointer dereference is a crash, not a security bugNull pointer dereference is a crash, not a security bugPosted Nov 5, 2007 15:26 UTC (Mon) by mheily (guest, #27123)In reply to: Thanks for proving Bernstein right by man_ls Parent article: Daniel Bernstein: ten years of qmail security
> Ehm, my C is a little rusty, but no :D I rather meant null pointer dereference, double dereference or whatever other strange things are allowed in C that lead to security problems. If a program attempts to dereference a NULL pointer, the program will be terminated immediately with a SIGSEGV signal. This does not allow arbitrary code to be executed. A double dereference is a perfectly normal and desirable condition in many programs, and the compiler will catch double-vs-single pointer mismatches at compile time. > Of course not, but I much rather prefer a NullPointerException than an undesired intrusion. Again, there is no way for a NULL pointer dereference to facilitate an intrusion since the program will segfault instead of executing arbitrary code.
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Null pointer dereference is a crash, not a security bug Posted Nov 5, 2007 17:51 UTC (Mon) by phiggins (subscriber, #5605) [Link] A lot of Java programmers have gotten so rusty on their C that they can't remember how Java saves them from these kinds of mistakes. It's actually the ArrayIndexOutOfBoundsException that saves your bacon from memory corruption. Of course, Java programmers are often way too smug and think that memory corruption problems are the only kinds of security bugs. It's very hard to write an arbitrary code execution vulnerability in Java, but an unexpected and improperly handled ArrayIndexOutOfBoundsException or NullPointerException could still violate the security of your program. It will be more difficult to get shell access that way than with arbitrary code execution, though! The bigger concern is with the JVM implementation, which has had some vulnerabilities, but it hasn't been nearly as bad as I expected it to be. Java really has done well in the memory-related security area.
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