kernel/linux.git/include/linux/fortify-string.h, branch v6.12.80

fortify: Fix incorrect reporting of read buffer size

2025-08-15T10:13:49+00:00

[ Upstream commit 94fd44648dae2a5b6149a41faa0b07928c3e1963 ] When FORTIFY_SOURCE reports about a run-time buffer overread, the wrong buffer size was being shown in the error message. (The bounds checking was correct.) Fixes: 3d965b33e40d ("fortify: Improve buffer overflow reporting") Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20250729231817.work.023-kees@kernel.org Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

fortify: Do not special-case 0-sized destinations

2024-06-19T20:32:04+00:00

All fake flexible arrays should have been removed now, so remove the special casing that was avoiding checking them. If a destination claims to be 0 sized, believe it. This is especially important for cases where __counted_by is in use and may have a 0 element count. Link: https://lore.kernel.org/r/20240619203105.work.747-kees@kernel.org Signed-off-by: Kees Cook

kasan, fortify: properly rename memintrinsics

2024-05-24T18:55:05+00:00

After commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") and the follow-up fixes, with CONFIG_FORTIFY_SOURCE enabled, even though the compiler instruments meminstrinsics by generating calls to __asan/__hwasan_ prefixed functions, FORTIFY_SOURCE still uses uninstrumented memset/memmove/memcpy as the underlying functions. As a result, KASAN cannot detect bad accesses in memset/memmove/memcpy. This also makes KASAN tests corrupt kernel memory and cause crashes. To fix this, use __asan_/__hwasan_memset/memmove/memcpy as the underlying functions whenever appropriate. Do this only for the instrumented code (as indicated by __SANITIZE_ADDRESS__). Link: https://lkml.kernel.org/r/20240517130118.759301-1-andrey.konovalov@linux.dev Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics") Fixes: 36be5cba99f6 ("kasan: treat meminstrinsic as builtins in uninstrumented files") Signed-off-by: Andrey Konovalov Reported-by: Erhard Furtner Reported-by: Nico Pache Closes: https://lore.kernel.org/all/20240501144156.17e65021@outsider.home/ Reviewed-by: Marco Elver Tested-by: Nico Pache Acked-by: Nico Pache Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Daniel Axtens Cc: Dmitry Vyukov Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-05-19T16:21:03+00:00

Pull mm updates from Andrew Morton: "The usual shower of singleton fixes and minor series all over MM, documented (hopefully adequately) in the respective changelogs. Notable series include: - Lucas Stach has provided some page-mapping cleanup/consolidation/ maintainability work in the series "mm/treewide: Remove pXd_huge() API". - In the series "Allow migrate on protnone reference with MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's MPOL_PREFERRED_MANY mode, yielding almost doubled performance in one test. - In their series "Memory allocation profiling" Kent Overstreet and Suren Baghdasaryan have contributed a means of determining (via /proc/allocinfo) whereabouts in the kernel memory is being allocated: number of calls and amount of memory. - Matthew Wilcox has provided the series "Various significant MM patches" which does a number of rather unrelated things, but in largely similar code sites. - In his series "mm: page_alloc: freelist migratetype hygiene" Johannes Weiner has fixed the page allocator's handling of migratetype requests, with resulting improvements in compaction efficiency. - In the series "make the hugetlb migration strategy consistent" Baolin Wang has fixed a hugetlb migration issue, which should improve hugetlb allocation reliability. - Liu Shixin has hit an I/O meltdown caused by readahead in a memory-tight memcg. Addressed in the series "Fix I/O high when memory almost met memcg limit". - In the series "mm/filemap: optimize folio adding and splitting" Kairui Song has optimized pagecache insertion, yielding ~10% performance improvement in one test. - Baoquan He has cleaned up and consolidated the early zone initialization code in the series "mm/mm_init.c: refactor free_area_init_core()". - Baoquan has also redone some MM initializatio code in the series "mm/init: minor clean up and improvement". - MM helper cleanups from Christoph Hellwig in his series "remove follow_pfn". - More cleanups from Matthew Wilcox in the series "Various page->flags cleanups". - Vlastimil Babka has contributed maintainability improvements in the series "memcg_kmem hooks refactoring". - More folio conversions and cleanups in Matthew Wilcox's series: "Convert huge_zero_page to huge_zero_folio" "khugepaged folio conversions" "Remove page_idle and page_young wrappers" "Use folio APIs in procfs" "Clean up __folio_put()" "Some cleanups for memory-failure" "Remove page_mapping()" "More folio compat code removal" - David Hildenbrand chipped in with "fs/proc/task_mmu: convert hugetlb functions to work on folis". - Code consolidation and cleanup work related to GUP's handling of hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2". - Rick Edgecombe has developed some fixes to stack guard gaps in the series "Cover a guard gap corner case". - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the series "mm/ksm: fix ksm exec support for prctl". - Baolin Wang has implemented NUMA balancing for multi-size THPs. This is a simple first-cut implementation for now. The series is "support multi-size THP numa balancing". - Cleanups to vma handling helper functions from Matthew Wilcox in the series "Unify vma_address and vma_pgoff_address". - Some selftests maintenance work from Dev Jain in the series "selftests/mm: mremap_test: Optimizations and style fixes". - Improvements to the swapping of multi-size THPs from Ryan Roberts in the series "Swap-out mTHP without splitting". - Kefeng Wang has significantly optimized the handling of arm64's permission page faults in the series "arch/mm/fault: accelerate pagefault when badaccess" "mm: remove arch's private VM_FAULT_BADMAP/BADACCESS" - GUP cleanups from David Hildenbrand in "mm/gup: consistently call it GUP-fast". - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault path to use struct vm_fault". - selftests build fixes from John Hubbard in the series "Fix selftests/mm build without requiring "make headers"". - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the series "Improved Memory Tier Creation for CPUless NUMA Nodes". Fixes the initialization code so that migration between different memory types works as intended. - David Hildenbrand has improved follow_pte() and fixed an errant driver in the series "mm: follow_pte() improvements and acrn follow_pte() fixes". - David also did some cleanup work on large folio mapcounts in his series "mm: mapcount for large folios + page_mapcount() cleanups". - Folio conversions in KSM in Alex Shi's series "transfer page to folio in KSM". - Barry Song has added some sysfs stats for monitoring multi-size THP's in the series "mm: add per-order mTHP alloc and swpout counters". - Some zswap cleanups from Yosry Ahmed in the series "zswap same-filled and limit checking cleanups". - Matthew Wilcox has been looking at buffer_head code and found the documentation to be lacking. The series is "Improve buffer head documentation". - Multi-size THPs get more work, this time from Lance Yang. His series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free" optimizes the freeing of these things. - Kemeng Shi has added more userspace-visible writeback instrumentation in the series "Improve visibility of writeback". - Kemeng Shi then sent some maintenance work on top in the series "Fix and cleanups to page-writeback". - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in the series "Improve anon_vma scalability for anon VMAs". Intel's test bot reported an improbable 3x improvement in one test. - SeongJae Park adds some DAMON feature work in the series "mm/damon: add a DAMOS filter type for page granularity access recheck" "selftests/damon: add DAMOS quota goal test" - Also some maintenance work in the series "mm/damon/paddr: simplify page level access re-check for pageout" "mm/damon: misc fixes and improvements" - David Hildenbrand has disabled some known-to-fail selftests ni the series "selftests: mm: cow: flag vmsplice() hugetlb tests as XFAIL". - memcg metadata storage optimizations from Shakeel Butt in "memcg: reduce memory consumption by memcg stats". - DAX fixes and maintenance work from Vishal Verma in the series "dax/bus.c: Fixups for dax-bus locking"" * tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits) memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault selftests: cgroup: add tests to verify the zswap writeback path mm: memcg: make alloc_mem_cgroup_per_node_info() return bool mm/damon/core: fix return value from damos_wmark_metric_value mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED selftests: cgroup: remove redundant enabling of memory controller Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT Docs/mm/damon/design: use a list for supported filters Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file selftests/damon: classify tests for functionalities and regressions selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None' selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts selftests/damon/_damon_sysfs: check errors from nr_schemes file reads mm/damon/core: initialize ->esz_bp from damos_quota_init_priv() selftests/damon: add a test for DAMOS quota goal ...

kunit/fortify: Fix replaced failure path to unbreak __alloc_size

2024-05-01T23:35:06+00:00

The __alloc_size annotation for kmemdup() was getting disabled under KUnit testing because the replaced fortify_panic macro implementation was using "return NULL" as a way to survive the sanity checking. But having the chance to return NULL invalidated __alloc_size, so kmemdup was not passing the __builtin_dynamic_object_size() tests any more: [23:26:18] [PASSED] fortify_test_alloc_size_kmalloc_const [23:26:19] # fortify_test_alloc_size_kmalloc_dynamic: EXPECTATION FAILED at lib/fortify_kunit.c:265 [23:26:19] Expected __builtin_dynamic_object_size(p, 1) == expected, but [23:26:19] __builtin_dynamic_object_size(p, 1) == -1 (0xffffffffffffffff) [23:26:19] expected == 11 (0xb) [23:26:19] __alloc_size() not working with __bdos on kmemdup("hello there", len, gfp) [23:26:19] [FAILED] fortify_test_alloc_size_kmalloc_dynamic Normal builds were not affected: __alloc_size continued to work there. Use a zero-sized allocation instead, which allows __alloc_size to behave. Fixes: 4ce615e798a7 ("fortify: Provide KUnit counters for failure testing") Fixes: fa4a3f86d498 ("fortify: Add KUnit tests for runtime overflows") Link: https://lore.kernel.org/r/20240501232937.work.532-kees@kernel.org Signed-off-by: Kees Cook

kunit/fortify: Add memcpy() tests

2024-04-30T17:34:30+00:00

Add fortify tests for memcpy() and memmove(). This can use a similar method to the fortify_panic() replacement, only we can do it for what was the WARN_ONCE(), which can be redefined. Since this is primarily testing the fortify behaviors of the memcpy() and memmove() defenses, the tests for memcpy() and memmove() are identical. Link: https://lore.kernel.org/r/20240429194342.2421639-3-keescook@chromium.org Signed-off-by: Kees Cook

mm/slab: enable slab allocation tagging for kmalloc and friends

2024-04-26T03:55:55+00:00

Redefine kmalloc, krealloc, kzalloc, kcalloc, etc. to record allocations and deallocations done by these functions. [surenb@google.com: undo _noprof additions in the documentation] Link: https://lkml.kernel.org/r/20240326231453.1206227-7-surenb@google.com [rdunlap@infradead.org: fix kcalloc() kernel-doc warnings] Link: https://lkml.kernel.org/r/20240327044649.9199-1-rdunlap@infradead.org Link: https://lkml.kernel.org/r/20240321163705.3067592-26-surenb@google.com Signed-off-by: Suren Baghdasaryan Co-developed-by: Kent Overstreet Signed-off-by: Kent Overstreet Signed-off-by: Randy Dunlap Reviewed-by: Kees Cook Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton

fortify: Improve buffer overflow reporting

2024-02-29T21:38:02+00:00

Improve the reporting of buffer overflows under CONFIG_FORTIFY_SOURCE to help accelerate debugging efforts. The calculations are all just sitting in registers anyway, so pass them along to the function to be reported. For example, before: detected buffer overflow in memcpy and after: memcpy: detected buffer overflow: 4096 byte read of buffer size 1 Link: https://lore.kernel.org/r/20230407192717.636137-10-keescook@chromium.org Signed-off-by: Kees Cook

fortify: Provide KUnit counters for failure testing

2024-02-29T21:38:02+00:00

The standard C string APIs were not designed to have a failure mode; they were expected to always succeed without memory safety issues. Normally, CONFIG_FORTIFY_SOURCE will use fortify_panic() to stop processing, as truncating a read or write may provide an even worse system state. However, this creates a problem for testing under things like KUnit, which needs a way to survive failures. When building with CONFIG_KUNIT, provide a failure path for all users of fortify_panic, and track whether the failure was a read overflow or a write overflow, for KUnit tests to examine. Inspired by similar logic in the slab tests. Signed-off-by: Kees Cook

fortify: Split reporting and avoid passing string pointer

2024-02-29T21:38:02+00:00

In preparation for KUnit testing and further improvements in fortify failure reporting, split out the report and encode the function and access failure (read or write overflow) into a single u8 argument. This mainly ends up saving a tiny bit of space in the data segment. For a defconfig with FORTIFY_SOURCE enabled: $ size gcc/vmlinux.before gcc/vmlinux.after text data bss dec hex filename 26132309 9760658 2195460 38088427 2452eeb gcc/vmlinux.before 26132386 9748382 2195460 38076228 244ff44 gcc/vmlinux.after Reviewed-by: Alexander Lobakin Signed-off-by: Kees Cook