On Tue, Nov 24, 2015 at 4:34 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > On Nov 24, 2015 1:38 PM, "Kees Cook" <keescook@xxxxxxxxxxxx> wrote: >> >> One of the easiest ways to protect the kernel from attack is to reduce >> the internal attack surface exposed when a "write" flaw is available. By >> making as much of the kernel read-only as possible, we reduce the >> attack surface. >> >> Many things are written to only during __init, and never changed >> again. These cannot be made "const" since the compiler will do the wrong >> thing (we do actually need to write to them). Instead, move these items >> into a memory region that will be made read-only during mark_rodata_ro() >> which happens after all kernel __init code has finished. >> >> This introduces __read_only as a way to mark such memory, and adds some >> documentation about the existing __read_mostly marking. > > Obligatory bikeshed: __ro_after_init, please. It's barely longer, > and it directly explains what's going on. __read_only makes me think > that it's really read-only and could, for example, actually be in ROM. I'm fine with that. Anyone else want to chime in before I send a v2? -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
