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  1. 02 Dec, 2015 5 commits
    • Ingo Molnar's avatar
      fs/proc, core/debug: Don't expose absolute kernel addresses via wchan · fddf5ac9
      Ingo Molnar authored 
      commit b2f73922 upstream.

So the /proc/PID/stat 'wchan' field (the 30th field, which contains
the absolute kernel address of the kernel function a task is blocked in)
leaks absolute kernel addresses to unprivileged user-space:

        seq_put_decimal_ull(m, ' ', wchan);

The absolute address might also leak via /proc/PID/wchan as well, if
KALLSYMS is turned off or if the symbol lookup fails for some reason:

static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
                          struct pid *pid, struct task_struct *task)
{
        unsigned long wchan;
        char symname[KSYM_NAME_LEN];

        wchan = get_wchan(task);

        if (lookup_symbol_name(wchan, symname) < 0) {
                if (!ptrace_may_access(task, PTRACE_MODE_READ))
                        return 0;
                seq_printf(m, "%lu", wchan);
        } else {
                seq_printf(m, "%s", symname);
        }

        return 0;
}

This isn't ideal, because for example it trivially leaks the KASLR offset
to any local attacker:

  fomalhaut:~> printf "%016lx\n" $(cat /proc/$$/stat | cut -d' ' -f35)
  ffffffff8123b380

Most real-life uses of wchan are symbolic:

  ps -eo pid:10,tid:10,wchan:30,comm

and procps uses /proc/PID/wchan, not the absolute address in /proc/PID/stat:

  triton:~/tip> strace -f ps -eo pid:10,tid:10,wchan:30,comm 2>&1 | grep wchan | tail -1
  open("/proc/30833/wchan", O_RDONLY)     = 6

There's one compatibility quirk here: procps relies on whether the
absolute value is non-zero - and we can provide that functionality
by outputing "0" or "1" depending on whether the task is blocked
(whether there's a wchan address).

These days there appears to be very little legitimate reason
user-space would be interested in  the absolute address. The
absolute address is mostly historic: from the days when we
didn't have kallsyms and user-space procps had to do the
decoding itself via the System.map.

So this patch sets all numeric output to "0" or "1" and keeps only
symbolic output, in /proc/PID/wchan.

( The absolute sleep address can generally still be profiled via
  perf, by tasks with sufficient privileges. )
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: kasan-dev <kasan-dev@googlegroups.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150930135917.GA3285@gmail.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
[ kamal: backport to 3.13-stable: proc_pid_wchan context ]
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      fddf5ac9
    • Boris BREZILLON's avatar
      mtd: mtdpart: fix add_mtd_partitions error path · 4e9e0c87
      Boris BREZILLON authored 
      commit e5bae867 upstream.

If we fail to allocate a partition structure in the middle of the partition
creation process, the already allocated partitions are never removed, which
means they are still present in the partition list and their resources are
never freed.
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      4e9e0c87
    • Maxime Ripard's avatar
      net: mvneta: Fix CPU_MAP registers initialisation · e55274c1
      Maxime Ripard authored 
      commit 2502d0ef upstream.

The CPU_MAP register is duplicated for each CPUs at different addresses,
each instance being at a different address.

However, the code so far was using CONFIG_NR_CPUS to initialise the CPU_MAP
registers for each registers, while the SoCs embed at most 4 CPUs.

This is especially an issue with multi_v7_defconfig, where CONFIG_NR_CPUS
is currently set to 16, resulting in writes to registers that are not
CPU_MAP.

Fixes: c5aff182 ("net: mvneta: driver for Marvell Armada 370/XP network unit")
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      e55274c1
    • Andrzej Hajda's avatar
      [media] v4l2-compat-ioctl32: fix alignment for ARM64 · 2beeada2
      Andrzej Hajda authored 
      commit 655e9780 upstream.

Alignment/padding rules on AMD64 and ARM64 differs. To allow properly match
compatible ioctls on ARM64 kernels without breaking AMD64 some fields
should be aligned using compat_s64 type and in one case struct should be
unpacked.
Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
[hans.verkuil@cisco.com: use compat_u64 instead of compat_s64 in v4l2_input32]
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      2beeada2
    • Richard Purdie's avatar
      HID: core: Avoid uninitialized buffer access · 963535ae
      Richard Purdie authored 
      commit 79b568b9 upstream.

hid_connect adds various strings to the buffer but they're all
conditional. You can find circumstances where nothing would be written
to it but the kernel will still print the supposedly empty buffer with
printk. This leads to corruption on the console/in the logs.

Ensure buf is initialized to an empty string.
Signed-off-by: default avatarRichard Purdie <richard.purdie@linuxfoundation.org>
[dvhart: Initialize string to "" rather than assign buf[0] = NULL;]
Cc: Jiri Kosina <jikos@kernel.org>
Cc: linux-input@vger.kernel.org
Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      963535ae
  3. 01 Dec, 2015 1 commit
  5. 30 Nov, 2015 13 commits
  7. 18 Nov, 2015 1 commit
  9. 13 Nov, 2015 20 commits
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