kernel.git/drivers/misc/lkdtm/bugs.c, branch linux-5.12.y

lkdtm/bugs: XFAIL UNALIGNED_LOAD_STORE_WRITE

2021-07-19T08:01:22Z

commit a15676ac8f24a9ac5fd881cf17be4be13fa0910a upstream. When built under CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, this test is expected to fail (i.e. not trip an exception). Fixes: 46d1a0f03d66 ("selftests/lkdtm: Add tests for LKDTM targets") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210623203936.3151093-5-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

lkdtm: tests for FORTIFY_SOURCE

2020-12-16T06:46:16Z

Add code to test both: - runtime detection of the overrun of a structure. This covers the __builtin_object_size(x, 0) case. This test is called FORTIFY_OBJECT. - runtime detection of the overrun of a char array within a structure. This covers the __builtin_object_size(x, 1) case which can be used for some string functions. This test is called FORTIFY_SUBOBJECT. Link: https://lkml.kernel.org/r/20201122162451.27551-3-laniel_francis@privacyrequired.com Signed-off-by: Daniel Axtens Signed-off-by: Francis Laniel Suggested-by: Kees Cook Reviewed-by: Kees Cook Cc: Daniel Micay Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lkdtm: remove set_fs-based tests

2020-09-09T02:21:34Z

Once we can't manipulate the address limit, we also can't test what happens when the manipulation is abused. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

misc: lkdtm: bugs: At least try to use popuated variable

2020-06-29T16:45:52Z

The result may not be intereresting, but not using a set variable is bad form and causes W=1 kernel builds to complain. Fixes the following W=1 warning(s): drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_STACK_GUARD_PAGE_LEADING’: drivers/misc/lkdtm/bugs.c:331:25: warning: variable ‘byte’ set but not used [-Wunused-but-set-variable] 331 | volatile unsigned char byte; | ^~~~ drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_STACK_GUARD_PAGE_TRAILING’: drivers/misc/lkdtm/bugs.c:345:25: warning: variable ‘byte’ set but not used [-Wunused-but-set-variable] 345 | volatile unsigned char byte; | ^~~~ Cc: Kees Cook Acked-by: Kees Cook Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20200626130525.389469-5-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman

lkdtm: Make arch-specific tests always available

2020-06-29T16:41:39Z

I'd like arch-specific tests to XFAIL when on a mismatched architecture so that we can more easily compare test coverage across all systems. Lacking kernel configs or CPU features count as a FAIL, not an XFAIL. Additionally fixes a build failure under 32-bit UML. Fixes: b09511c253e5 ("lkdtm: Add a DOUBLE_FAULT crash type on x86") Fixes: cea23efb4de2 ("lkdtm/bugs: Make double-fault test always available") Fixes: 6cb6982f42cb ("lkdtm: arm64: test kernel pointer authentication") Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20200625203704.317097-5-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

lkdtm: Avoid more compiler optimizations for bad writes

2020-06-29T16:41:39Z

It seems at least Clang is able to throw away writes it knows are destined for read-only memory, which makes things like the WRITE_RO test fail, as the write gets elided. Instead, force the variable to be volatile, and make similar changes through-out other tests in an effort to avoid needing to repeat fixing these kinds of problems. Also includes pr_err() calls in failure paths so that kernel logs are more clear in the failure case. Reported-by: Prasad Sodagudi Suggested-by: Sami Tolvanen Fixes: 9ae113ce5faf ("lkdtm: add tests for additional page permissions") Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20200625203704.317097-2-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

lkdtm: bugs: Fix spelling mistake

2020-04-23T14:30:09Z

Fix spelling mistake s/Intentially/Intentionally Signed-off-by: Gustavo A. R. Silva Acked-by: Kees Cook Link: https://lore.kernel.org/r/20200401182855.GA16253@embeddedor Signed-off-by: Greg Kroah-Hartman

drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks

2020-04-07T17:43:44Z

Adds LKDTM tests for arithmetic overflow (both signed and unsigned), as well as array bounds checking. Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Acked-by: Dmitry Vyukov Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dan Carpenter Cc: Elena Petrova Cc: "Gustavo A. R. Silva" Link: http://lkml.kernel.org/r/20200227193516.32566-4-keescook@chromium.org Signed-off-by: Linus Torvalds

lkdtm: arm64: test kernel pointer authentication

2020-03-18T09:50:21Z

This test is specific for arm64. When in-kernel Pointer Authentication config is enabled, the return address stored in the stack is signed. This feature helps in ROP kind of attack. If any parameters used to generate the pac () is modified then this will fail in the authentication stage and will lead to abort. This test changes the input parameter APIA kernel keys to cause abort. The pac computed from the new key can be same as last due to hash collision so this is retried for few times as there is no reliable way to compare the pacs. Even though this test may fail even after retries but this may cause authentication failure at a later stage in earlier function returns. This test can be invoked as, echo CORRUPT_PAC > /sys/kernel/debug/provoke-crash/DIRECT or as below if inserted as a module, insmod lkdtm.ko cpoint_name=DIRECT cpoint_type=CORRUPT_PAC cpoint_count=1 [ 13.118166] lkdtm: Performing direct entry CORRUPT_PAC [ 13.118298] lkdtm: Clearing PAC from the return address [ 13.118466] Unable to handle kernel paging request at virtual address bfff8000108648ec [ 13.118626] Mem abort info: [ 13.118666] ESR = 0x86000004 [ 13.118866] EC = 0x21: IABT (current EL), IL = 32 bits [ 13.118966] SET = 0, FnV = 0 [ 13.119117] EA = 0, S1PTW = 0 Signed-off-by: Amit Daniel Kachhap Acked-by: Catalin Marinas Cc: Kees Cook Signed-off-by: Catalin Marinas

lkdtm/bugs: fix build error in lkdtm_UNSET_SMEP

2020-01-14T14:41:04Z

When building ARCH=um with CONFIG_UML_X86=y and CONFIG_64BIT=y we get the build errors: drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_UNSET_SMEP’: drivers/misc/lkdtm/bugs.c:288:8: error: implicit declaration of function ‘native_read_cr4’ [-Werror=implicit-function-declaration] cr4 = native_read_cr4(); ^~~~~~~~~~~~~~~ drivers/misc/lkdtm/bugs.c:290:13: error: ‘X86_CR4_SMEP’ undeclared (first use in this function); did you mean ‘X86_FEATURE_SMEP’? if ((cr4 & X86_CR4_SMEP) != X86_CR4_SMEP) { ^~~~~~~~~~~~ X86_FEATURE_SMEP drivers/misc/lkdtm/bugs.c:290:13: note: each undeclared identifier is reported only once for each function it appears in drivers/misc/lkdtm/bugs.c:297:2: error: implicit declaration of function ‘native_write_cr4’; did you mean ‘direct_write_cr4’? [-Werror=implicit-function-declaration] native_write_cr4(cr4); ^~~~~~~~~~~~~~~~ direct_write_cr4 So specify that this block of code should only build when CONFIG_X86_64=y *AND* CONFIG_UML is unset. Signed-off-by: Brendan Higgins Acked-by: Kees Cook Link: https://lore.kernel.org/r/20191213003522.66450-1-brendanhiggins@google.com Signed-off-by: Greg Kroah-Hartman