Eric Lee / smarc-fsl-linux-kernel

17 Jan, 2020

2 commits

  • be6da9842   livepatch/samples/selftest: Use klp_shadow_alloc() API correctly ... Browse Code »

    The commit e91c2518a5d22a ("livepatch: Initialize shadow variables
    safely by a custom callback") leads to the following static checker
    warning:

    samples/livepatch/livepatch-shadow-fix1.c:86 livepatch_fix1_dummy_alloc()
    error: 'klp_shadow_alloc()' 'leak' too small (4 vs 8)

    It is because klp_shadow_alloc() is used a wrong way:

    int *leak;
    shadow_leak = klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
    shadow_leak_ctor, leak);

    The code is supposed to store the "leak" pointer into the shadow variable.
    3rd parameter correctly passes size of the data (size of pointer). But
    the 5th parameter is wrong. It should pass pointer to the data (pointer
    to the pointer) but it passes the pointer directly.

    It works because shadow_leak_ctor() handle "ctor_data" as the data
    instead of pointer to the data. But it is semantically wrong and
    confusing.

    The same problem is also in the module used by selftests. In this case,
    "pvX" variables are introduced. They represent the data stored in
    the shadow variables.

    Reported-by: Dan Carpenter
    Signed-off-by: Petr Mladek
    Reviewed-by: Joe Lawrence
    Acked-by: Miroslav Benes
    Reviewed-by: Kamalesh Babulal
    Signed-off-by: Jiri Kosina

    Petr Mladek
     
  • c24c57a4c   livepatch/selftest: Clean up shadow variable names and type ... Browse Code »

    The shadow variable selftest is quite tricky. Especially it is problematic
    to understand what values are stored, returned, and printed.

    Make it easier to understand by using "int *var, **sv" variables
    consistently everywhere instead of the generic "void *", "ret",
    and "ctor_data".

    Signed-off-by: Petr Mladek
    Reviewed-by: Joe Lawrence
    Acked-by: Miroslav Benes
    Reviewed-by: Kamalesh Babulal
    Signed-off-by: Jiri Kosina

    Petr Mladek
     

01 Nov, 2019

1 commit

06 Feb, 2019

2 commits

  • 49ee4dd2e   livepatch: Proper error handling in the shadow variables selftest ... Browse Code »

    Add proper error handling when allocating or getting shadow variables
    in the selftest. It prevents an invalid pointer access in some situations.
    It shows the good programming practice in the others.

    The error codes are just the best guess and specific for this particular
    test. In general, klp_shadow_alloc() returns NULL also when the given
    shadow variable has already been allocated. In addition, both
    klp_shadow_alloc() and klp_shadow_get_or_alloc() might fail from
    other reasons when the constructor fails.

    Note, that the error code is not really important even in the real life.
    The use of shadow variables should be transparent for the original
    livepatched code.

    Acked-by: Miroslav Benes
    Acked-by: Joe Lawrence
    Signed-off-by: Petr Mladek

    Petr Mladek
     
  • 86e43f23c   livepatch: return -ENOMEM on ptr_id() allocation failure ... Browse Code »

    Fixes the following smatch warning:

    lib/livepatch/test_klp_shadow_vars.c:47 ptr_id() warn: returning -1 instead of -ENOMEM is sloppy

    Signed-off-by: Joe Lawrence
    Acked-by: Miroslav Benes
    Signed-off-by: Petr Mladek

    Joe Lawrence
     

12 Jan, 2019

1 commit

  • a2818ee4d   selftests/livepatch: introduce tests ... Browse Code »

    Add a few livepatch modules and simple target modules that the included
    regression suite can run tests against:

    - basic livepatching (multiple patches, atomic replace)
    - pre/post (un)patch callbacks
    - shadow variable API

    Signed-off-by: Joe Lawrence
    Signed-off-by: Petr Mladek
    Tested-by: Miroslav Benes
    Tested-by: Alice Ferrazzi
    Acked-by: Joe Lawrence
    Acked-by: Josh Poimboeuf
    Signed-off-by: Jiri Kosina

    Joe Lawrence