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2020-09-08lkdtm: remove set_fs-based testsChristoph Hellwig1-10/+0
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 <[email protected]> Signed-off-by: Al Viro <[email protected]>
2020-06-29misc: lkdtm: bugs: At least try to use popuated variableLee Jones1-2/+2
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 <[email protected]> Acked-by: Kees Cook <[email protected]> Signed-off-by: Lee Jones <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-06-29lkdtm: Make arch-specific tests always availableKees Cook1-17/+21
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 <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-06-29lkdtm: Avoid more compiler optimizations for bad writesKees Cook1-6/+5
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 <[email protected]> Suggested-by: Sami Tolvanen <[email protected]> Fixes: 9ae113ce5faf ("lkdtm: add tests for additional page permissions") Signed-off-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-04-23lkdtm: bugs: Fix spelling mistakeGustavo A. R. Silva1-1/+1
Fix spelling mistake s/Intentially/Intentionally Signed-off-by: Gustavo A. R. Silva <[email protected]> Acked-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/20200401182855.GA16253@embeddedor Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-04-07drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checksKees Cook1-0/+75
Adds LKDTM tests for arithmetic overflow (both signed and unsigned), as well as array bounds checking. Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Acked-by: Dmitry Vyukov <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Andrey Konovalov <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Elena Petrova <[email protected]> Cc: "Gustavo A. R. Silva" <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
2020-03-18lkdtm: arm64: test kernel pointer authenticationAmit Daniel Kachhap1-0/+36
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 (<key, sp, lr>) 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 <[email protected]> Acked-by: Catalin Marinas <[email protected]> Cc: Kees Cook <[email protected]> Signed-off-by: Catalin Marinas <[email protected]>
2020-01-14lkdtm/bugs: fix build error in lkdtm_UNSET_SMEPBrendan Higgins1-1/+1
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 <[email protected]> Acked-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-01-14lkdtm/bugs: Make double-fault test always availableKees Cook1-4/+6
Adjust the DOUBLE_FAULT test to always be available (so test harnesses don't have to make exceptions more missing tests), and for the arch-specific tests to "XFAIL" so that test harnesses can reason about expected vs unexpected failures. Fixes: b09511c253e5 ("lkdtm: Add a DOUBLE_FAULT crash type on x86") Signed-off-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/202001021226.751D3F869D@keescook Signed-off-by: Greg Kroah-Hartman <[email protected]>
2019-11-26lkdtm: Add a DOUBLE_FAULT crash type on x86Andy Lutomirski1-0/+39
The DOUBLE_FAULT crash does INT $8, which is a decent approximation of a double fault. This is useful for testing the double fault handling. Use it like: Signed-off-by: Andy Lutomirski <[email protected]> Cc: Kees Cook <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Linus Torvalds <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
2019-09-02Merge 5.3-rc7 into char-misc-nextGreg Kroah-Hartman1-2/+2
We need the fixes in here as well for testing and merges Signed-off-by: Greg Kroah-Hartman <[email protected]>
2019-08-28lkdtm/bugs: fix build error in lkdtm_EXHAUST_STACKRaul E Rangel1-2/+2
lkdtm/bugs.c:94:2: error: format '%d' expects argument of type 'int', but argument 2 has type 'long unsigned int' [-Werror=format=] pr_info("Calling function with %d frame size to depth %d ...\n", ^ THREAD_SIZE is defined as a unsigned long, cast CONFIG_FRAME_WARN to unsigned long as well. Fixes: 24cccab42c419 ("lkdtm/bugs: Adjust recursion test to avoid elision") Cc: stable <[email protected]> Signed-off-by: Raul E Rangel <[email protected]> Acked-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2019-08-19lkdtm: Split WARNING into separate testsKees Cook1-1/+6
There are three paths through the kernel code exception logging: - BUG (no configurable printk message) - WARN_ON (no configurable printk message) - WARN (configurable printk message) LKDTM was not testing WARN_ON(). This is needed to evaluate the placement of the "cut here" line, which needs special handling in each of the three exceptions (and between architectures that implement instruction exceptions to implement the code exceptions). Signed-off-by: Kees Cook <[email protected]>
2019-07-11Merge tag 'char-misc-5.3-rc1' of ↵Linus Torvalds1-0/+66
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char / misc driver updates from Greg KH: "Here is the "large" pull request for char and misc and other assorted smaller driver subsystems for 5.3-rc1. It seems that this tree is becoming the funnel point of lots of smaller driver subsystems, which is fine for me, but that's why it is getting larger over time and does not just contain stuff under drivers/char/ and drivers/misc. Lots of small updates all over the place here from different driver subsystems: - habana driver updates - coresight driver updates - documentation file movements and updates - Android binder fixes and updates - extcon driver updates - google firmware driver updates - fsi driver updates - smaller misc and char driver updates - soundwire driver updates - nvmem driver updates - w1 driver fixes All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (188 commits) coresight: Do not default to CPU0 for missing CPU phandle dt-bindings: coresight: Change CPU phandle to required property ocxl: Allow contexts to be attached with a NULL mm fsi: sbefifo: Don't fail operations when in SBE IPL state coresight: tmc: Smatch: Fix potential NULL pointer dereference coresight: etm3x: Smatch: Fix potential NULL pointer dereference coresight: Potential uninitialized variable in probe() coresight: etb10: Do not call smp_processor_id from preemptible coresight: tmc-etf: Do not call smp_processor_id from preemptible coresight: tmc-etr: alloc_perf_buf: Do not call smp_processor_id from preemptible coresight: tmc-etr: Do not call smp_processor_id() from preemptible docs: misc-devices: convert files without extension to ReST fpga: dfl: fme: align PR buffer size per PR datawidth fpga: dfl: fme: remove copy_to_user() in ioctl for PR fpga: dfl-fme-mgr: fix FME_PR_INTFC_ID register address. intel_th: msu: Start read iterator from a non-empty window intel_th: msu: Split sgt array and pointer in multiwindow mode intel_th: msu: Support multipage blocks intel_th: pci: Add Ice Lake NNPI support intel_th: msu: Fix single mode with disabled IOMMU ...
2019-07-08Merge branch 'siginfo-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull force_sig() argument change from Eric Biederman: "A source of error over the years has been that force_sig has taken a task parameter when it is only safe to use force_sig with the current task. The force_sig function is built for delivering synchronous signals such as SIGSEGV where the userspace application caused a synchronous fault (such as a page fault) and the kernel responded with a signal. Because the name force_sig does not make this clear, and because the force_sig takes a task parameter the function force_sig has been abused for sending other kinds of signals over the years. Slowly those have been fixed when the oopses have been tracked down. This set of changes fixes the remaining abusers of force_sig and carefully rips out the task parameter from force_sig and friends making this kind of error almost impossible in the future" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits) signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus signal: Remove the signal number and task parameters from force_sig_info signal: Factor force_sig_info_to_task out of force_sig_info signal: Generate the siginfo in force_sig signal: Move the computation of force into send_signal and correct it. signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal signal: Remove the task parameter from force_sig_fault signal: Use force_sig_fault_to_task for the two calls that don't deliver to current signal: Explicitly call force_sig_fault on current signal/unicore32: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from ptrace_break signal/nds32: Remove tsk parameter from send_sigtrap signal/riscv: Remove tsk parameter from do_trap signal/sh: Remove tsk parameter from force_sig_info_fault signal/um: Remove task parameter from send_sigtrap signal/x86: Remove task parameter from send_sigtrap signal: Remove task parameter from force_sig_mceerr signal: Remove task parameter from force_sig signal: Remove task parameter from force_sigsegv ...
2019-06-23lkdtm: Check for SMEP clearing protectionsKees Cook1-0/+66
This adds an x86-specific test for pinned cr4 bits. A successful test will validate pinning and check the ROP-style call-middle-of-function defense, if needed. For example, in the case of native_write_cr4() looking like this: ffffffff8171bce0 <native_write_cr4>: ffffffff8171bce0: 48 8b 35 79 46 f2 00 mov 0xf24679(%rip),%rsi ffffffff8171bce7: 48 09 f7 or %rsi,%rdi ffffffff8171bcea: 0f 22 e7 mov %rdi,%cr4 ... ffffffff8171bd5a: c3 retq The UNSET_SMEP test will jump to ffffffff8171bcea (the mov to cr4) instead of ffffffff8171bce0 (native_write_cr4() entry) to simulate a direct-call bypass attempt. Expected successful results: # echo UNSET_SMEP > /sys/kernel/debug/provoke-crash/DIRECT # dmesg [ 79.594433] lkdtm: Performing direct entry UNSET_SMEP [ 79.596459] lkdtm: trying to clear SMEP normally [ 79.598406] lkdtm: ok: SMEP did not get cleared [ 79.599981] lkdtm: trying to clear SMEP with call gadget [ 79.601810] ------------[ cut here ]------------ [ 79.603421] Attempt to unpin cr4 bits: 100000; bypass attack?! ... [ 79.650170] ---[ end trace 2452ca0f6126242e ]--- [ 79.650937] lkdtm: ok: SMEP removal was reverted Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2019-05-27signal: Remove task parameter from force_sigEric W. Biederman1-1/+1
All of the remaining callers pass current into force_sig so remove the task parameter to make this obvious and to make misuse more difficult in the future. This also makes it clear force_sig passes current into force_sig_info. Signed-off-by: "Eric W. Biederman" <[email protected]>
2019-04-07lkdtm/bugs: Adjust recursion test to avoid elisionKees Cook1-6/+17
While I was able to trick gcc into keeping a pathological recursion, Clang was not so easily fooled. Instead, switch to using "volatile" and side-effects to keep the stack variable allocated and to run the function. Additionally renames "OVERFLOW" to "EXHAUST_STACK" to better describe the test. Signed-off-by: Kees Cook <[email protected]>
2018-03-06lkdtm: Relocate code to subdirectoryKees Cook1-0/+257
The LKDTM modules keep expanding, and it's getting weird to have each file get a prefix. Instead, move to a subdirectory for cleaner handling. Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>