kernel/drivers/misc/lkdtm, branch linux-5.1.y

lkdtm: support llvm-objcopy

2019-07-14T06:09:51Z

commit e9e08a07385e08f1a7f85c5d1e345c21c9564963 upstream. With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors: llvm-objcopy: error: --set-section-flags=.text conflicts with --rename-section=.text=.rodata Rather than support setting flags then renaming sections vs renaming then setting flags, it's simpler to just change both at the same time via --rename-section. Adding the load flag is required for GNU objcopy to mark .rodata Type as PROGBITS after the rename. This can be verified with: $ readelf -S drivers/misc/lkdtm/rodata_objcopy.o ... Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 1] .rodata PROGBITS 0000000000000000 00000040 0000000000000004 0000000000000000 A 0 0 4 ... Which shows that .text is now renamed .rodata, the alloc flag A is set, the type is PROGBITS, and the section is not flagged as writeable W. Cc: stable@vger.kernel.org Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554 Link: https://github.com/ClangBuiltLinux/linux/issues/448 Reported-by: Nathan Chancellor Suggested-by: Alan Modra Suggested-by: Jordan Rupprect Suggested-by: Kees Cook Acked-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Signed-off-by: Greg Kroah-Hartman

lkdtm/usercopy: Moves the KERNEL_DS test to non-canonical

2019-06-25T03:34:47Z

[ Upstream commit 2bf8496f6e9b7e9a557f65eb95eab16fea7958c7 ] The prior implementation of the KERNEL_DS fault checking would work on any unmapped kernel address, but this was narrowed to the non-canonical range instead. This adjusts the LKDTM test to match. Fixes: 00c42373d397 ("x86-64: add warning for non-canonical user access address dereferences") Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

lkdtm: change snprintf to scnprintf for possible overflow

2019-01-18T15:34:05Z

Change snprintf to scnprintf. There are generally two cases where using snprintf causes problems. 1) Uses of size += snprintf(buf, SIZE - size, fmt, ...) In this case, if snprintf would have written more characters than what the buffer size (SIZE) is, then size will end up larger than SIZE. In later uses of snprintf, SIZE - size will result in a negative number, leading to problems. Note that size might already be too large by using size = snprintf before the code reaches a case of size += snprintf. 2) If size is ultimately used as a length parameter for a copy back to user space, then it will potentially allow for a buffer overflow and information disclosure when size is greater than SIZE. When the size is used to index the buffer directly, we can have memory corruption. This also means when size = snprintf... is used, it may also cause problems since size may become large. Copying to userspace is mitigated by the HARDENED_USERCOPY kernel configuration. The solution to these issues is to use scnprintf which returns the number of characters actually written to the buffer, so the size variable will never exceed SIZE. Signed-off-by: Silvio Cesare Cc: Dan Carpenter Cc: Will Deacon Cc: Greg KH Acked-by: Kees Cook Signed-off-by: Willy Tarreau Signed-off-by: Greg Kroah-Hartman

lkdtm: Add tests for NULL pointer dereference

2019-01-09T20:00:31Z

Introduce lkdtm tests for NULL pointer dereference: check access or exec at NULL address, since these errors tend to be reported differently from the general fault error text. For example from x86: pr_alert("BUG: unable to handle kernel %s at %px\n", address < PAGE_SIZE ? "NULL pointer dereference" : "paging request", (void *)address); Signed-off-by: Christophe Leroy Signed-off-by: Kees Cook

lkdtm: Print real addresses

2019-01-09T19:58:51Z

Today, when doing a lkdtm test before the readiness of the random generator, (ptrval) is printed instead of the address at which it perform the fault: [ 1597.337030] lkdtm: Performing direct entry EXEC_USERSPACE [ 1597.337142] lkdtm: attempting ok execution at (ptrval) [ 1597.337398] lkdtm: attempting bad execution at (ptrval) [ 1597.337460] kernel tried to execute user page (77858000) -exploit attempt? (uid: 0) [ 1597.344769] Unable to handle kernel paging request for instruction fetch [ 1597.351392] Faulting instruction address: 0x77858000 [ 1597.356312] Oops: Kernel access of bad area, sig: 11 [#1] If the lkdtm test is done later on, it prints an hashed address. In both cases this is pointless. The purpose of the test is to ensure the kernel generates an Oops at the expected address, so real addresses needs to be printed. This patch fixes that. Signed-off-by: Christophe Leroy Signed-off-by: Kees Cook

lkdtm: Do not depend on BLOCK and clean up headers

2019-01-09T19:58:51Z

After the transition to kprobes, symbols are resolved at runtime. This means there is no need to have all the Kconfig and header logic to avoid build failures. This also paves the way to having arbitrary test locations. Reported-by: Christophe Leroy Signed-off-by: Kees Cook

Merge tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-11-01T18:46:27Z

Pull stackleak gcc plugin from Kees Cook: "Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin was ported from grsecurity by Alexander Popov. It provides efficient stack content poisoning at syscall exit. This creates a defense against at least two classes of flaws: - Uninitialized stack usage. (We continue to work on improving the compiler to do this in other ways: e.g. unconditional zero init was proposed to GCC and Clang, and more plugin work has started too). - Stack content exposure. By greatly reducing the lifetime of valid stack contents, exposures via either direct read bugs or unknown cache side-channels become much more difficult to exploit. This complements the existing buddy and heap poisoning options, but provides the coverage for stacks. The x86 hooks are included in this series (which have been reviewed by Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already been merged through the arm64 tree (written by Laura Abbott and reviewed by Mark Rutland and Will Deacon). With VLAs having been removed this release, there is no need for alloca() protection, so it has been removed from the plugin" * tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: arm64: Drop unneeded stackleak_check_alloca() stackleak: Allow runtime disabling of kernel stack erasing doc: self-protection: Add information about STACKLEAK feature fs/proc: Show STACKLEAK metrics in the /proc file system lkdtm: Add a test for STACKLEAK gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls

Merge tag 'char-misc-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2018-10-26T16:11:43Z

Pull char/misc driver updates from Greg KH: "Here is the big set of char/misc patches for 4.20-rc1. Loads of things here, we have new code in all of these driver subsystems: - fpga - stm - extcon - nvmem - eeprom - hyper-v - gsmi - coresight - thunderbolt - vmw_balloon - goldfish - soundwire along with lots of fixes and minor changes to other small drivers. All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (245 commits) Documentation/security-bugs: Clarify treatment of embargoed information lib: Fix ia64 bootloader linkage MAINTAINERS: Clarify UIO vs UIOVEC maintainer docs/uio: fix a grammar nitpick docs: fpga: document programming fpgas using regions fpga: add devm_fpga_region_create fpga: bridge: add devm_fpga_bridge_create fpga: mgr: add devm_fpga_mgr_create hv_balloon: Replace spin_is_locked() with lockdep sgi-xp: Replace spin_is_locked() with lockdep eeprom: New ee1004 driver for DDR4 memory eeprom: at25: remove unneeded 'at25_remove' w1: IAD Register is yet readable trough iad sys file. Fix snprintf (%u for unsigned, count for max size). misc: mic: scif: remove set but not used variables 'src_dma_addr, dst_dma_addr' misc: mic: fix a DMA pool free failure platform: goldfish: pipe: Add a blank line to separate varibles and code platform: goldfish: pipe: Remove redundant casting platform: goldfish: pipe: Call misc_deregister if init fails platform: goldfish: pipe: Move the file-scope goldfish_pipe_dev variable into the driver state platform: goldfish: pipe: Move the file-scope goldfish_pipe_miscdev variable into the driver state ...

misc: lkdtm: fixed static variable initialization

2018-09-12T07:46:46Z

Resolved "ERROR: do not initialise statics to 0" Signed-off-by: Parth Y Shah Signed-off-by: Greg Kroah-Hartman

lkdtm: Add a test for STACKLEAK

2018-09-04T17:35:47Z

Introduce an lkdtm test for the STACKLEAK feature: check that the current task stack is properly erased (filled with STACKLEAK_POISON). Signed-off-by: Alexander Popov Signed-off-by: Tycho Andersen Tested-by: Laura Abbott Signed-off-by: Kees Cook