Messages in this thread | | | Subject | Re: [PATCH v2] printk: hash addresses printed with %p | From | Joe Perches <> | Date | Mon, 16 Oct 2017 22:20:08 -0700 |
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On Tue, 2017-10-17 at 15:52 +1100, Tobin C. Harding wrote: > Currently there are many places in the kernel where addresses are being > printed using an unadorned %p. Kernel pointers should be printed using > %pK allowing some control via the kptr_restrict sysctl. Exposing addresses > gives attackers sensitive information about the kernel layout in memory. > > We can reduce the attack surface by hashing all addresses printed with > %p. This will of course break some users, forcing code printing needed > addresses to be updated. > > For what it's worth, usage of unadorned %p can be broken down as follows > > git grep '%p[^KFfSsBRrbMmIiEUVKNhdDgCGO]' | wc -l
Not really. There are many asm uses included there
I think a better grep is:
$ git grep -E '%p[^A-Za-z0-9]' | cut -f1 -d"/" | sort | uniq -c 1084 arch 20 block 10 crypto 32 Documentation 8121 drivers 1221 fs 143 include 101 kernel 69 lib 100 mm 1510 net 40 samples 7 scripts 11 security 166 sound 152 tools 2 virt
> arch: 2512
arch is especially overestimated.
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