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2020-07-27kill elf_fpxregs_tAl Viro
all uses are conditional upon ELF_CORE_COPY_XFPREGS, which has not been defined on any architecture since 2010 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27introduction of regset ->get() wrappers, switching ELF coredumps to thoseAl Viro
Two new helpers: given a process and regset, dump into a buffer. regset_get() takes a buffer and size, regset_get_alloc() takes size and allocates a buffer. Return value in both cases is the amount of data actually dumped in case of success or -E... on error. In both cases the size is capped by regset->n * regset->size, so ->get() is called with offset 0 and size no more than what regset expects. binfmt_elf.c callers of ->get() are switched to using those; the other caller (copy_regset_to_user()) will need some preparations to switch. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-06-10Merge branch 'uaccess.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc uaccess updates from Al Viro: "Assorted uaccess patches for this cycle - the stuff that didn't fit into thematic series" * 'uaccess.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user() user_regset_copyout_zero(): use clear_user() TEST_ACCESS_OK _never_ had been checked anywhere x86: switch cp_stat64() to unsafe_put_user() binfmt_flat: don't use __put_user() binfmt_elf_fdpic: don't use __... uaccess primitives binfmt_elf: don't bother with __{put,copy_to}_user() pselect6() and friends: take handling the combined 6th/7th args into helper
2020-06-04Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge yet more updates from Andrew Morton: - More MM work. 100ish more to go. Mike Rapoport's "mm: remove __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue - Various other little subsystems * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits) lib/ubsan.c: fix gcc-10 warnings tools/testing/selftests/vm: remove duplicate headers selftests: vm: pkeys: fix multilib builds for x86 selftests: vm: pkeys: use the correct page size on powerpc selftests/vm/pkeys: override access right definitions on powerpc selftests/vm/pkeys: test correct behaviour of pkey-0 selftests/vm/pkeys: introduce a sub-page allocator selftests/vm/pkeys: detect write violation on a mapped access-denied-key page selftests/vm/pkeys: associate key on a mapped page and detect write violation selftests/vm/pkeys: associate key on a mapped page and detect access violation selftests/vm/pkeys: improve checks to determine pkey support selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust() selftests/vm/pkeys: fix number of reserved powerpc pkeys selftests/vm/pkeys: introduce powerpc support selftests/vm/pkeys: introduce generic pkey abstractions selftests: vm: pkeys: use the correct huge page size selftests/vm/pkeys: fix alloc_random_pkey() to make it really random selftests/vm/pkeys: fix assertion in pkey_disable_set/clear() selftests/vm/pkeys: fix pkey_disable_clear() selftests: vm: pkeys: add helpers for pkey bits ...
2020-06-04fs/binfmt_elf: remove redundant elf_map ifndefAnthony Iliopoulos
The ifndef was added a long time ago to support archs that would define their own mapping function. The last user was the metag arch which was removed from the tree, and as such there are no users left. Let's kill it. Signed-off-by: Anthony Iliopoulos <ailiop@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200402161543.4119-1-ailiop@suse.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04Merge branch 'exec-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull execve updates from Eric Biederman: "Last cycle for the Nth time I ran into bugs and quality of implementation issues related to exec that could not be easily be fixed because of the way exec is implemented. So I have been digging into exec and cleanup up what I can. I don't think I have exec sorted out enough to fix the issues I started with but I have made some headway this cycle with 4 sets of changes. - promised cleanups after introducing exec_update_mutex - trivial cleanups for exec - control flow simplifications - remove the recomputation of bprm->cred The net result is code that is a bit easier to understand and work with and a decrease in the number of lines of code (if you don't count the added tests)" * 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits) exec: Compute file based creds only once exec: Add a per bprm->file version of per_clear binfmt_elf_fdpic: fix execfd build regression selftests/exec: Add binfmt_script regression test exec: Remove recursion from search_binary_handler exec: Generic execfd support exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC exec: Move the call of prepare_binprm into search_binary_handler exec: Allow load_misc_binary to call prepare_binprm unconditionally exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds exec: Teach prepare_exec_creds how exec treats uids & gids exec: Set the point of no return sooner exec: Move handling of the point of no return to the top level exec: Run sync_mm_rss before taking exec_update_mutex exec: Fix spelling of search_binary_handler in a comment exec: Move the comment from above de_thread to above unshare_sighand exec: Rename flush_old_exec begin_new_exec exec: Move most of setup_new_exec into flush_old_exec exec: In setup_new_exec cache current in the local variable me ...
2020-06-03binfmt_elf: don't bother with __{put,copy_to}_user()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-06-01Merge branch 'work.set_fs-exec' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull uaccess/coredump updates from Al Viro: "set_fs() removal in coredump-related area - mostly Christoph's stuff..." * 'work.set_fs-exec' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump binfmt_elf: remove the set_fs in fill_siginfo_note signal: refactor copy_siginfo_to_user32 powerpc/spufs: simplify spufs core dumping powerpc/spufs: stop using access_ok powerpc/spufs: fix copy_to_user while atomic
2020-06-01Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "A sizeable pile of arm64 updates for 5.8. Summary below, but the big two features are support for Branch Target Identification and Clang's Shadow Call stack. The latter is currently arm64-only, but the high-level parts are all in core code so it could easily be adopted by other architectures pending toolchain support Branch Target Identification (BTI): - Support for ARMv8.5-BTI in both user- and kernel-space. This allows branch targets to limit the types of branch from which they can be called and additionally prevents branching to arbitrary code, although kernel support requires a very recent toolchain. - Function annotation via SYM_FUNC_START() so that assembly functions are wrapped with the relevant "landing pad" instructions. - BPF and vDSO updates to use the new instructions. - Addition of a new HWCAP and exposure of BTI capability to userspace via ID register emulation, along with ELF loader support for the BTI feature in .note.gnu.property. - Non-critical fixes to CFI unwind annotations in the sigreturn trampoline. Shadow Call Stack (SCS): - Support for Clang's Shadow Call Stack feature, which reserves platform register x18 to point at a separate stack for each task that holds only return addresses. This protects function return control flow from buffer overruns on the main stack. - Save/restore of x18 across problematic boundaries (user-mode, hypervisor, EFI, suspend, etc). - Core support for SCS, should other architectures want to use it too. - SCS overflow checking on context-switch as part of the existing stack limit check if CONFIG_SCHED_STACK_END_CHECK=y. CPU feature detection: - Removed numerous "SANITY CHECK" errors when running on a system with mismatched AArch32 support at EL1. This is primarily a concern for KVM, which disabled support for 32-bit guests on such a system. - Addition of new ID registers and fields as the architecture has been extended. Perf and PMU drivers: - Minor fixes and cleanups to system PMU drivers. Hardware errata: - Unify KVM workarounds for VHE and nVHE configurations. - Sort vendor errata entries in Kconfig. Secure Monitor Call Calling Convention (SMCCC): - Update to the latest specification from Arm (v1.2). - Allow PSCI code to query the SMCCC version. Software Delegated Exception Interface (SDEI): - Unexport a bunch of unused symbols. - Minor fixes to handling of firmware data. Pointer authentication: - Add support for dumping the kernel PAC mask in vmcoreinfo so that the stack can be unwound by tools such as kdump. - Simplification of key initialisation during CPU bringup. BPF backend: - Improve immediate generation for logical and add/sub instructions. vDSO: - Minor fixes to the linker flags for consistency with other architectures and support for LLVM's unwinder. - Clean up logic to initialise and map the vDSO into userspace. ACPI: - Work around for an ambiguity in the IORT specification relating to the "num_ids" field. - Support _DMA method for all named components rather than only PCIe root complexes. - Minor other IORT-related fixes. Miscellaneous: - Initialise debug traps early for KGDB and fix KDB cacheflushing deadlock. - Minor tweaks to early boot state (documentation update, set TEXT_OFFSET to 0x0, increase alignment of PE/COFF sections). - Refactoring and cleanup" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits) KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h KVM: arm64: Check advertised Stage-2 page size capability arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() ACPI/IORT: Remove the unused __get_pci_rid() arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register arm64/cpufeature: Add remaining feature bits in ID_PFR0 register arm64/cpufeature: Introduce ID_MMFR5 CPU register arm64/cpufeature: Introduce ID_DFR1 CPU register arm64/cpufeature: Introduce ID_PFR2 CPU register arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0 arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register arm64: mm: Add asid_gen_match() helper firmware: smccc: Fix missing prototype warning for arm_smccc_version_init arm64: vdso: Fix CFI directives in sigreturn trampoline arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction ...
2020-05-28fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info()Alexander Potapenko
KMSAN reported uninitialized data being written to disk when dumping core. As a result, several kilobytes of kmalloc memory may be written to the core file and then read by a non-privileged user. Reported-by: sam <sunhaoyl@outlook.com> Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200419100848.63472-1-glider@google.com Link: https://github.com/google/kmsan/issues/76 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-21exec: Generic execfd supportEric W. Biederman
Most of the support for passing the file descriptor of an executable to an interpreter already lives in the generic code and in binfmt_elf. Rework the fields in binfmt_elf that deal with executable file descriptor passing to make executable file descriptor passing a first class concept. Move the fd_install from binfmt_misc into begin_new_exec after the new creds have been installed. This means that accessing the file through /proc/<pid>/fd/N is able to see the creds for the new executable before allowing access to the new executables files. Performing the install of the executables file descriptor after the point of no return also means that nothing special needs to be done on error. The exiting of the process will close all of it's open files. Move the would_dump from binfmt_misc into begin_new_exec right after would_dump is called on the bprm->file. This makes it obvious this case exists and that no nesting of bprm->file is currently supported. In binfmt_misc the movement of fd_install into generic code means that it's special error exit path is no longer needed. Link: https://lkml.kernel.org/r/87y2poyd91.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-07exec: Rename flush_old_exec begin_new_execEric W. Biederman
There is and has been for a very long time been a lot more going on in flush_old_exec than just flushing the old state. After the movement of code from setup_new_exec there is a whole lot more going on than just flushing the old executables state. Rename flush_old_exec to begin_new_exec to more accurately reflect what this function does. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-07exec: Merge install_exec_creds into setup_new_execEric W. Biederman
The two functions are now always called one right after the other so merge them together to make future maintenance easier. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-05binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dumpChristoph Hellwig
There is no logic in elf_core_dump itself or in the various arch helpers called from it which use uaccess routines on kernel pointers except for the file writes thate are nicely encapsulated by using __kernel_write in dump_emit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-05binfmt_elf: remove the set_fs in fill_siginfo_noteEric W. Biederman
The code in binfmt_elf.c is differnt from the rest of the code that processes siginfo, as it sends siginfo from a kernel buffer to a file rather than from kernel memory to userspace buffers. To remove it's use of set_fs the code needs some different siginfo helpers. Add the helper copy_siginfo_to_external to copy from the kernel's internal siginfo layout to a buffer in the siginfo layout that userspace expects. Modify fill_siginfo_note to use copy_siginfo_to_external instead of set_fs and copy_siginfo_to_user. Update compat_binfmt_elf.c to use the previously added copy_siginfo_to_external32 to handle the compat case. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-05Merge branch 'for-next/bti-user' into for-next/btiWill Deacon
Merge in user support for Branch Target Identification, which narrowly missed the cut for 5.7 after a late ABI concern. * for-next/bti-user: arm64: bti: Document behaviour for dynamically linked binaries arm64: elf: Fix allnoconfig kernel build with !ARCH_USE_GNU_PROPERTY arm64: BTI: Add Kconfig entry for userspace BTI mm: smaps: Report arm64 guarded pages in smaps arm64: mm: Display guarded pages in ptdump KVM: arm64: BTI: Reset BTYPE when skipping emulated instructions arm64: BTI: Reset BTYPE when skipping emulated instructions arm64: traps: Shuffle code to eliminate forward declarations arm64: unify native/compat instruction skipping arm64: BTI: Decode BYTPE bits when printing PSTATE arm64: elf: Enable BTI at exec based on ELF program properties elf: Allow arch to tweak initial mmap prot flags arm64: Basic Branch Target Identification support ELF: Add ELF program property parsing support ELF: UAPI and Kconfig additions for ELF program properties
2020-04-07fs/binfmt_elf.c: don't free interpreter's ELF pheaders on common pathAlexey Dobriyan
Static executables don't need to free NULL pointer. It doesn't matter really because static executable is not common scenario but do it anyway out of pedantry. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200219185330.GA4933@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07fs/binfmt_elf.c: allocate less for static executableAlexey Dobriyan
PT_INTERP ELF header can be spared if executable is static. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200219185012.GB4871@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07fs/binfmt_elf.c: delete "loc" variableAlexey Dobriyan
"loc" variable became just a wrapper for PT_INTERP ELF header after main ELF header was moved to "bprm->buf". Delete it. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200219184847.GA4871@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/vma: replace all remaining open encodings with is_vm_hugetlb_page()Anshuman Khandual
This replaces all remaining open encodings with is_vm_hugetlb_page(). Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Will Deacon <will@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nick Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guo Ren <guoren@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/1582520593-30704-4-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-16elf: Allow arch to tweak initial mmap prot flagsDave Martin
An arch may want to tweak the mmap prot flags for an ELFexecutable's initial mappings. For example, arm64 is going to need to add PROT_BTI for executable pages in an ELF process whose executable is marked as using Branch Target Identification (an ARMv8.5-A control flow integrity feature). So that this can be done in a generic way, add a hook arch_elf_adjust_prot() to modify the prot flags as desired: arches can select CONFIG_HAVE_ELF_PROT and implement their own backend where necessary. By default, leave the prot flags unchanged. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-16ELF: Add ELF program property parsing supportDave Martin
ELF program properties will be needed for detecting whether to enable optional architecture or ABI features for a new ELF process. For now, there are no generic properties that we care about, so do nothing unless CONFIG_ARCH_USE_GNU_PROPERTY=y. Otherwise, the presence of properties using the PT_PROGRAM_PROPERTY phdrs entry (if any), and notify each property to the arch code. For now, the added code is not used. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-01-31fs/binfmt_elf.c: coredump: allow process with empty address space to coredumpAlexey Dobriyan
Unmapping whole address space at once with munmap(0, (1ULL<<47) - 4096) or equivalent will create empty coredump. It is silly way to exit, however registers content may still be useful. The right to coredump is fundamental right of a process! Link: http://lkml.kernel.org/r/20191222150137.GA1277@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: coredump: delete duplicated overflow checkAlexey Dobriyan
array_size() macro will do overflow check anyway. Link: http://lkml.kernel.org/r/20191222144009.GB24341@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: coredump: allocate core ELF header on stackAlexey Dobriyan
Comment says ELF header is "too large to be on stack". 64 bytes on 64-bit is not large by any means. Link: http://lkml.kernel.org/r/20191222143850.GA24341@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: make BAD_ADDR() unlikelyAlexey Dobriyan
If some mapping goes past TASK_SIZE it will be rejected by kernel which means no such userspace binaries exist. Mark every such check as unlikely. Link: http://lkml.kernel.org/r/20191215124355.GA21124@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: better codegen around current->mmAlexey Dobriyan
"current->mm" pointer is stable in general except few cases one of which execve(2). Compiler can't treat is as stable but it _is_ stable most of the time. During ELF loading process ->mm becomes stable right after flush_old_exec(). Help compiler by caching current->mm, otherwise it continues to refetch it. add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-141 (-141) Function old new delta elf_core_dump 5062 5039 -23 load_elf_binary 5426 5308 -118 Note: other cases are left as is because it is either pessimisation or no change in binary size. Link: http://lkml.kernel.org/r/20191215124755.GB21124@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: don't copy ELF header aroundAlexey Dobriyan
ELF header is read into bprm->buf[] by generic execve code. Save a memcpy and allocate just one header for the interpreter instead of two headers (64 bytes instead of 128 on 64-bit). Link: http://lkml.kernel.org/r/20191208171242.GA19716@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: fix ->start_code calculationAlexey Dobriyan
Only executable segments should be accounted to ->start_code just like they do to ->end_code (correctly). Link: http://lkml.kernel.org/r/20191208171410.GB19716@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31fs/binfmt_elf.c: smaller code generation around auxv vector fillAlexey Dobriyan
Filling auxv vector as array with index (auxv[i++] = ...) generates terrible code. "saved_auxv" should be reworked because it is the worst member of mm_struct by size/usefullness ratio but do it later. Meanwhile help gcc a little with *auxv++ idiom. Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-127 (-127) Function old new delta load_elf_binary 5470 5343 -127 Link: http://lkml.kernel.org/r/20191208172301.GD19716@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04fs/binfmt_elf.c: extract elf_read() functionAlexey Dobriyan
ELF reads done by the kernel have very complicated error detection code which better live in one place. Link: http://lkml.kernel.org/r/20191005165215.GB26927@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04fs/binfmt_elf.c: delete unused "interp_map_addr" argumentAlexey Dobriyan
Link: http://lkml.kernel.org/r/20191005165049.GA26927@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15y2038: elfcore: Use __kernel_old_timeval for process timesArnd Bergmann
We store elapsed time for a crashed process in struct elf_prstatus using 'timeval' structures. Once glibc starts using 64-bit time_t, this becomes incompatible with the kernel's idea of timeval since the structure layout no longer matches on 32-bit architectures. This changes the definition of the elf_prstatus structure to use __kernel_old_timeval instead, which is hardcoded to the currently used binary layout. There is no risk of overflow in y2038 though, because the time values are all relative times, and can store up to 68 years of process elapsed time. There is a risk of applications breaking at build time when they use the new kernel headers and expect the type to be exactly 'timeval' rather than a structure that has the same fields as before. Those applications have to be modified to deal with 64-bit time_t anyway. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-06elf: don't use MAP_FIXED_NOREPLACE for elf executable mappingsLinus Torvalds
In commit 4ed28639519c ("fs, elf: drop MAP_FIXED usage from elf_map") we changed elf to use MAP_FIXED_NOREPLACE instead of MAP_FIXED for the executable mappings. Then, people reported that it broke some binaries that had overlapping segments from the same file, and commit ad55eac74f20 ("elf: enforce MAP_FIXED on overlaying elf segments") re-instated MAP_FIXED for some overlaying elf segment cases. But only some - despite the summary line of that commit, it only did it when it also does a temporary brk vma for one obvious overlapping case. Now Russell King reports another overlapping case with old 32-bit x86 binaries, which doesn't trigger that limited case. End result: we had better just drop MAP_FIXED_NOREPLACE entirely, and go back to MAP_FIXED. Yes, it's a sign of old binaries generated with old tool-chains, but we do pride ourselves on not breaking existing setups. This still leaves MAP_FIXED_NOREPLACE in place for the load_elf_interp() and the old load_elf_library() use-cases, because nobody has reported breakage for those. Yet. Note that in all the cases seen so far, the overlapping elf sections seem to be just re-mapping of the same executable with different section attributes. We could possibly introduce a new MAP_FIXED_NOFILECHANGE flag or similar, which acts like NOREPLACE, but allows just remapping the same executable file using different protection flags. It's not clear that would make a huge difference to anything, but if people really hate that "elf remaps over previous maps" behavior, maybe at least a more limited form of remapping would alleviate some concerns. Alternatively, we should take a look at our elf_map() logic to see if we end up not mapping things properly the first time. In the meantime, this is the minimal "don't do that then" patch while people hopefully think about it more. Reported-by: Russell King <linux@armlinux.org.uk> Fixes: 4ed28639519c ("fs, elf: drop MAP_FIXED usage from elf_map") Fixes: ad55eac74f20 ("elf: enforce MAP_FIXED on overlaying elf segments") Cc: Michal Hocko <mhocko@suse.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26binfmt_elf: Do not move brk for INTERP-less ET_EXECKees Cook
When brk was moved for binaries without an interpreter, it should have been limited to ET_DYN only. In other words, the special case was an ET_DYN that lacks an INTERP, not just an executable that lacks INTERP. The bug manifested for giant static executables, where the brk would end up in the middle of the text area on 32-bit architectures. Reported-and-tested-by: Richard Kojedzinszky <richard@kojedz.in> Fixes: bbdc6076d2e5 ("binfmt_elf: move brk out of mmap when doing direct loader exec") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm, fs: move randomize_stack_top from fs to mmAlexandre Ghiti
Patch series "Provide generic top-down mmap layout functions", v6. This series introduces generic functions to make top-down mmap layout easily accessible to architectures, in particular riscv which was the initial goal of this series. The generic implementation was taken from arm64 and used successively by arm, mips and finally riscv. Note that in addition the series fixes 2 issues: - stack randomization was taken into account even if not necessary. - [1] fixed an issue with mmap base which did not take into account randomization but did not report it to arm and mips, so by moving arm64 into a generic library, this problem is now fixed for both architectures. This work is an effort to factorize architecture functions to avoid code duplication and oversights as in [1]. [1]: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html This patch (of 14): This preparatory commit moves this function so that further introduction of generic topdown mmap layout is contained only in mm/util.c. Link: http://lkml.kernel.org/r/20190730055113.23635-2-alex@ghiti.fr Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-16fs/binfmt_elf.c: delete stale commentAlexey Dobriyan
"passed_fileno" variable was deleted 11 years ago in 2.6.25. Link: http://lkml.kernel.org/r/20190529201747.GA23248@avx2 Fixes: d20894a23708 ("Remove a.out interpreter support in ELF loader") Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-21treewide: Add SPDX license identifier for more missed filesThomas Gleixner
Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14binfmt_elf: move brk out of mmap when doing direct loader execKees Cook
Commmit eab09532d400 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE"), made changes in the rare case when the ELF loader was directly invoked (e.g to set a non-inheritable LD_LIBRARY_PATH, testing new versions of the loader), by moving into the mmap region to avoid both ET_EXEC and PIE binaries. This had the effect of also moving the brk region into mmap, which could lead to the stack and brk being arbitrarily close to each other. An unlucky process wouldn't get its requested stack size and stack allocations could end up scribbling on the heap. This is illustrated here. In the case of using the loader directly, brk (so helpfully identified as "[heap]") is allocated with the _loader_ not the binary. For example, with ASLR entirely disabled, you can see this more clearly: $ /bin/cat /proc/self/maps 555555554000-55555555c000 r-xp 00000000 ... /bin/cat 55555575b000-55555575c000 r--p 00007000 ... /bin/cat 55555575c000-55555575d000 rw-p 00008000 ... /bin/cat 55555575d000-55555577e000 rw-p 00000000 ... [heap] ... 7ffff7ff7000-7ffff7ffa000 r--p 00000000 ... [vvar] 7ffff7ffa000-7ffff7ffc000 r-xp 00000000 ... [vdso] 7ffff7ffc000-7ffff7ffd000 r--p 00027000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffd000-7ffff7ffe000 rw-p 00028000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffe000-7ffff7fff000 rw-p 00000000 ... 7ffffffde000-7ffffffff000 rw-p 00000000 ... [stack] $ /lib/x86_64-linux-gnu/ld-2.27.so /bin/cat /proc/self/maps ... 7ffff7bcc000-7ffff7bd4000 r-xp 00000000 ... /bin/cat 7ffff7bd4000-7ffff7dd3000 ---p 00008000 ... /bin/cat 7ffff7dd3000-7ffff7dd4000 r--p 00007000 ... /bin/cat 7ffff7dd4000-7ffff7dd5000 rw-p 00008000 ... /bin/cat 7ffff7dd5000-7ffff7dfc000 r-xp 00000000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7fb2000-7ffff7fd6000 rw-p 00000000 ... 7ffff7ff7000-7ffff7ffa000 r--p 00000000 ... [vvar] 7ffff7ffa000-7ffff7ffc000 r-xp 00000000 ... [vdso] 7ffff7ffc000-7ffff7ffd000 r--p 00027000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffd000-7ffff7ffe000 rw-p 00028000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffe000-7ffff8020000 rw-p 00000000 ... [heap] 7ffffffde000-7ffffffff000 rw-p 00000000 ... [stack] The solution is to move brk out of mmap and into ELF_ET_DYN_BASE since nothing is there in the direct loader case (and ET_EXEC is still far away at 0x400000). Anything that ran before should still work (i.e. the ultimately-launched binary already had the brk very far from its text, so this should be no different from a COMPAT_BRK standpoint). The only risk I see here is that if someone started to suddenly depend on the entire memory space lower than the mmap region being available when launching binaries via a direct loader execs which seems highly unlikely, I'd hope: this would mean a binary would _not_ work when exec()ed normally. (Note that this is only done under CONFIG_ARCH_HAS_ELF_RANDOMIZATION when randomization is turned on.) Link: http://lkml.kernel.org/r/20190422225727.GA21011@beast Link: https://lkml.kernel.org/r/CAGXu5jJ5sj3emOT2QPxQkNQk0qbU6zEfu9=Omfhx_p0nCKPSjA@mail.gmail.com Fixes: eab09532d400 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE") Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Ali Saidi <alisaidi@amazon.com> Cc: Ali Saidi <alisaidi@amazon.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14elf: init pt_regs pointer laterAlexey Dobriyan
Get "current_pt_regs" pointer right before usage. Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-180 (-180) Function old new delta load_elf_binary 5806 5626 -180 !!! Looks like the compiler doesn't know that "current_pt_regs" is stable pointer (because it doesn't know ->stack isn't) even though it knows that "current" is stable pointer. So it saves it in the very beginning and then tries to carry it through a lot of code. Here is what happens here: load_elf_binary() ... mov rax,QWORD PTR gs:0x14c00 mov r13,QWORD PTR [rax+0x18] r13 = current->stack call kmem_cache_alloc # first kmalloc [980 bytes later!] # let's spill that sucker because we need a register # for "load_bias" calculations at # # if (interpreter) { # load_bias = ELF_ET_DYN_BASE; # if (current->flags & PF_RANDOMIZE) # load_bias += arch_mmap_rnd(); # elf_flags |= elf_fixed; # } mov QWORD PTR [rsp+0x68],r13 If this is not _the_ root cause it is still eeeeh. After the patch things become much simpler: mov rax, QWORD PTR gs:0x14c00 # current mov rdx, QWORD PTR [rax+0x18] # current->stack movq [rdx+0x3fb8], 0 # fill pt_regs ... call finalize_exec Link: http://lkml.kernel.org/r/20190419200343.GA19788@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Tested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: extract PROT_* calculationsAlexey Dobriyan
There are two places where mapping protections are calculated: one for executable, another one for interpreter -- take them out. ELF read and execute permissions are interchanged with Linux PROT_READ and PROT_EXEC, microoptimizations are welcome! Link: http://lkml.kernel.org/r/20190417213413.GB26474@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs//binfmt_elf.c: move variables initialization closer to their usageAlexey Dobriyan
Link: http://lkml.kernel.org/r/20190416202002.GB24304@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: save 1 indent levelAlexey Dobriyan
Rewrite for (...) { if (->p_type == PT_INTERP) { ... break; } } loop into for (...) { if (->p_type != PT_INTERP) continue; ... break; } Link: http://lkml.kernel.org/r/20190416201906.GA24304@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: delete trailing "return;" in functions returning "void"Alexey Dobriyan
Link: http://lkml.kernel.org/r/20190314205042.GE18143@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: free PT_INTERP filename ASAPAlexey Dobriyan
There is no reason for PT_INTERP filename to linger till the end of the whole loading process. Link: http://lkml.kernel.org/r/20190314204953.GD18143@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Nikitas Angelinas <nikitas.angelinas@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mukesh Ojha <mojha@codeaurora.org> [nikitas.angelinas@gmail.com: fix GPF when dereferencing invalid interpreter] Link: http://lkml.kernel.org/r/20190330140032.GA1527@vostro Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: make scope of "pos" variable smallerAlexey Dobriyan
Link: http://lkml.kernel.org/r/20190314204707.GC18143@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14fs/binfmt_elf.c: remove unneeded initialization of mm->start_stackAndrew Morton
As pointed out by zoujc@lenovo.com, setup_arg_pages() already initialized current->mm->start_stack. Link: https://bugzilla.kernel.org/show_bug.cgi?id=202881 Reported-by: <zoujc@lenovo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07fs/binfmt_elf.c: spread const a littleAlexey Dobriyan
Link: http://lkml.kernel.org/r/20190204202830.GC27482@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07fs/binfmt_elf.c: use list_for_each_entry()Alexey Dobriyan
[adobriyan@gmail.com: fixup compilation] Link: http://lkml.kernel.org/r/20190205064334.GA2152@avx2 Link: http://lkml.kernel.org/r/20190204202800.GB27482@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07fs/binfmt_elf.c: don't be afraid of overflowAlexey Dobriyan
Number of ELF program headers is 16-bit by spec, so total size comfortably fits into "unsigned int". Space savings: 7 bytes! add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-7 (-7) Function old new delta load_elf_phdrs 137 130 -7 Link: http://lkml.kernel.org/r/20190204202715.GA27482@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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