https://github.com/torvalds/linux
Revision c1e63117711977cc4295b2ce73de29dd17066c82 authored by David Hildenbrand on 20 November 2021, 00:43:58 UTC, committed by Linus Torvalds on 20 November 2021, 18:35:55 UTC
To clear a user buffer we cannot simply use memset, we have to use
clear_user(). With a virtio-mem device that registers a vmcore_cb and
has some logically unplugged memory inside an added Linux memory block,
I can easily trigger a BUG by copying the vmcore via "cp":
systemd[1]: Starting Kdump Vmcore Save Service...
kdump[420]: Kdump is using the default log level(3).
kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/
kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/
kdump[465]: saving vmcore-dmesg.txt complete
kdump[467]: saving vmcore
BUG: unable to handle page fault for address: 00007f2374e01000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867
Oops: 0003 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014
RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86
Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 <49> c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81
RSP: 0018:ffffc9000073be08 EFLAGS: 00010212
RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000
RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008
RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50
R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000
R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8
FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0
Call Trace:
read_vmcore+0x236/0x2c0
proc_reg_read+0x55/0xa0
vfs_read+0x95/0x190
ksys_read+0x4f/0xc0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Some x86-64 CPUs have a CPU feature called "Supervisor Mode Access
Prevention (SMAP)", which is used to detect wrong access from the kernel
to user buffers like this: SMAP triggers a permissions violation on
wrong access. In the x86-64 variant of clear_user(), SMAP is properly
handled via clac()+stac().
To fix, properly use clear_user() when we're dealing with a user buffer.
Link: https://lkml.kernel.org/r/20211112092750.6921-1-david@redhat.com
Fixes: 997c136f518c ("fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 825c43f
Tip revision: c1e63117711977cc4295b2ce73de29dd17066c82 authored by David Hildenbrand on 20 November 2021, 00:43:58 UTC
proc/vmcore: fix clearing user buffer by properly using clear_user()
proc/vmcore: fix clearing user buffer by properly using clear_user()
Tip revision: c1e6311
| File | Mode | Size |
|---|---|---|
| 842 | ||
| crypto | ||
| dim | ||
| fonts | ||
| kunit | ||
| livepatch | ||
| lz4 | ||
| lzo | ||
| math | ||
| mpi | ||
| pldmfw | ||
| raid6 | ||
| reed_solomon | ||
| test_fortify | ||
| vdso | ||
| xz | ||
| zlib_deflate | ||
| zlib_dfltcc | ||
| zlib_inflate | ||
| zstd | ||
| .gitignore | -rw-r--r-- | 159 bytes |
| Kconfig | -rw-r--r-- | 16.1 KB |
| Kconfig.debug | -rw-r--r-- | 86.1 KB |
| Kconfig.kasan | -rw-r--r-- | 7.3 KB |
| Kconfig.kcsan | -rw-r--r-- | 9.5 KB |
| Kconfig.kfence | -rw-r--r-- | 3.2 KB |
| Kconfig.kgdb | -rw-r--r-- | 5.6 KB |
| Kconfig.ubsan | -rw-r--r-- | 6.3 KB |
| Makefile | -rw-r--r-- | 13.3 KB |
| argv_split.c | -rw-r--r-- | 2.1 KB |
| ashldi3.c | -rw-r--r-- | 541 bytes |
| ashrdi3.c | -rw-r--r-- | 565 bytes |
| asn1_decoder.c | -rw-r--r-- | 13.2 KB |
| asn1_encoder.c | -rw-r--r-- | 10.3 KB |
| assoc_array.c | -rw-r--r-- | 51.7 KB |
| atomic64.c | -rw-r--r-- | 4.6 KB |
| atomic64_test.c | -rw-r--r-- | 6.4 KB |
| audit.c | -rw-r--r-- | 1.9 KB |
| bcd.c | -rw-r--r-- | 297 bytes |
| bch.c | -rw-r--r-- | 38.3 KB |
| bitfield_kunit.c | -rw-r--r-- | 4.4 KB |
| bitmap.c | -rw-r--r-- | 44.9 KB |
| bitrev.c | -rw-r--r-- | 1.9 KB |
| bootconfig.c | -rw-r--r-- | 21.1 KB |
| bsearch.c | -rw-r--r-- | 1.2 KB |
| btree.c | -rw-r--r-- | 19.2 KB |
| bucket_locks.c | -rw-r--r-- | 1.4 KB |
| bug.c | -rw-r--r-- | 5.9 KB |
| build_OID_registry | -rwxr-xr-x | 4.5 KB |
| buildid.c | -rw-r--r-- | 5.0 KB |
| bust_spinlocks.c | -rw-r--r-- | 676 bytes |
| check_signature.c | -rw-r--r-- | 635 bytes |
| checksum.c | -rw-r--r-- | 4.1 KB |
| clz_ctz.c | -rw-r--r-- | 1.2 KB |
| clz_tab.c | -rw-r--r-- | 891 bytes |
| cmdline.c | -rw-r--r-- | 5.8 KB |
| cmdline_kunit.c | -rw-r--r-- | 4.2 KB |
| cmpdi2.c | -rw-r--r-- | 501 bytes |
| compat_audit.c | -rw-r--r-- | 1002 bytes |
| cpu_rmap.c | -rw-r--r-- | 7.6 KB |
| cpumask.c | -rw-r--r-- | 7.1 KB |
| crc-ccitt.c | -rw-r--r-- | 5.6 KB |
| crc-itu-t.c | -rw-r--r-- | 2.7 KB |
| crc-t10dif.c | -rw-r--r-- | 3.2 KB |
| crc16.c | -rw-r--r-- | 2.7 KB |
| crc32.c | -rw-r--r-- | 9.3 KB |
| crc32defs.h | -rw-r--r-- | 1.6 KB |
| crc32test.c | -rw-r--r-- | 37.4 KB |
| crc4.c | -rw-r--r-- | 1003 bytes |
| crc64.c | -rw-r--r-- | 1.8 KB |
| crc7.c | -rw-r--r-- | 2.5 KB |
| crc8.c | -rw-r--r-- | 2.4 KB |
| ctype.c | -rw-r--r-- | 1.4 KB |
| debug_info.c | -rw-r--r-- | 782 bytes |
| debug_locks.c | -rw-r--r-- | 1.2 KB |
| debugobjects.c | -rw-r--r-- | 35.4 KB |
| dec_and_lock.c | -rw-r--r-- | 1.2 KB |
| decompress.c | -rw-r--r-- | 1.8 KB |
| decompress_bunzip2.c | -rw-r--r-- | 23.5 KB |
| decompress_inflate.c | -rw-r--r-- | 4.8 KB |
| decompress_unlz4.c | -rw-r--r-- | 4.2 KB |
| decompress_unlzma.c | -rw-r--r-- | 15.8 KB |
| decompress_unlzo.c | -rw-r--r-- | 6.4 KB |
| decompress_unxz.c | -rw-r--r-- | 10.9 KB |
| decompress_unzstd.c | -rw-r--r-- | 10.2 KB |
| devmem_is_allowed.c | -rw-r--r-- | 683 bytes |
| devres.c | -rw-r--r-- | 14.9 KB |
| digsig.c | -rw-r--r-- | 5.5 KB |
| dump_stack.c | -rw-r--r-- | 3.0 KB |
| dynamic_debug.c | -rw-r--r-- | 27.9 KB |
| dynamic_queue_limits.c | -rw-r--r-- | 4.3 KB |
| earlycpio.c | -rw-r--r-- | 3.6 KB |
| errname.c | -rw-r--r-- | 3.7 KB |
| error-inject.c | -rw-r--r-- | 5.5 KB |
| errseq.c | -rw-r--r-- | 6.6 KB |
| extable.c | -rw-r--r-- | 2.9 KB |
| fault-inject-usercopy.c | -rw-r--r-- | 823 bytes |
| fault-inject.c | -rw-r--r-- | 5.9 KB |
| fdt.c | -rw-r--r-- | 69 bytes |
| fdt_addresses.c | -rw-r--r-- | 79 bytes |
| fdt_empty_tree.c | -rw-r--r-- | 80 bytes |
| fdt_ro.c | -rw-r--r-- | 72 bytes |
| fdt_rw.c | -rw-r--r-- | 72 bytes |
| fdt_strerror.c | -rw-r--r-- | 78 bytes |
| fdt_sw.c | -rw-r--r-- | 72 bytes |
| fdt_wip.c | -rw-r--r-- | 73 bytes |
| find_bit.c | -rw-r--r-- | 3.3 KB |
| find_bit_benchmark.c | -rw-r--r-- | 3.9 KB |
| flex_proportions.c | -rw-r--r-- | 7.2 KB |
| gen_crc32table.c | -rw-r--r-- | 3.3 KB |
| gen_crc64table.c | -rw-r--r-- | 1.4 KB |
| genalloc.c | -rw-r--r-- | 26.4 KB |
| generic-radix-tree.c | -rw-r--r-- | 5.3 KB |
| glob.c | -rw-r--r-- | 3.5 KB |
| globtest.c | -rw-r--r-- | 4.2 KB |
| hexdump.c | -rw-r--r-- | 7.4 KB |
| hweight.c | -rw-r--r-- | 1.9 KB |
| idr.c | -rw-r--r-- | 17.5 KB |
| inflate.c | -rw-r--r-- | 38.7 KB |
| interval_tree.c | -rw-r--r-- | 540 bytes |
| interval_tree_test.c | -rw-r--r-- | 3.4 KB |
| iomap.c | -rw-r--r-- | 9.1 KB |
| iomap_copy.c | -rw-r--r-- | 2.2 KB |
| iommu-helper.c | -rw-r--r-- | 755 bytes |
| iov_iter.c | -rw-r--r-- | 49.5 KB |
| irq_poll.c | -rw-r--r-- | 5.4 KB |
| irq_regs.c | -rw-r--r-- | 394 bytes |
| is_single_threaded.c | -rw-r--r-- | 1.2 KB |
| kasprintf.c | -rw-r--r-- | 1.4 KB |
| kfifo.c | -rw-r--r-- | 12.1 KB |
| klist.c | -rw-r--r-- | 10.4 KB |
| kobject.c | -rw-r--r-- | 28.2 KB |
| kobject_uevent.c | -rw-r--r-- | 18.9 KB |
| kstrtox.c | -rw-r--r-- | 10.7 KB |
| kstrtox.h | -rw-r--r-- | 411 bytes |
| libcrc32c.c | -rw-r--r-- | 2.0 KB |
| linear_ranges.c | -rw-r--r-- | 8.1 KB |
| list-test.c | -rw-r--r-- | 17.4 KB |
| list_debug.c | -rw-r--r-- | 1.8 KB |
| list_sort.c | -rw-r--r-- | 8.2 KB |
| llist.c | -rw-r--r-- | 2.5 KB |
| locking-selftest-hardirq.h | -rw-r--r-- | 246 bytes |
| locking-selftest-mutex.h | -rw-r--r-- | 159 bytes |
| locking-selftest-rlock-hardirq.h | -rw-r--r-- | 74 bytes |
| locking-selftest-rlock-softirq.h | -rw-r--r-- | 74 bytes |
| locking-selftest-rlock.h | -rw-r--r-- | 197 bytes |
| locking-selftest-rsem.h | -rw-r--r-- | 202 bytes |
| locking-selftest-rtmutex.h | -rw-r--r-- | 162 bytes |
| locking-selftest-softirq.h | -rw-r--r-- | 246 bytes |
| locking-selftest-spin-hardirq.h | -rw-r--r-- | 73 bytes |
| locking-selftest-spin-softirq.h | -rw-r--r-- | 73 bytes |
| locking-selftest-spin.h | -rw-r--r-- | 157 bytes |
| locking-selftest-wlock-hardirq.h | -rw-r--r-- | 74 bytes |
| locking-selftest-wlock-softirq.h | -rw-r--r-- | 74 bytes |
| locking-selftest-wlock.h | -rw-r--r-- | 197 bytes |
| locking-selftest-wsem.h | -rw-r--r-- | 202 bytes |
| locking-selftest.c | -rw-r--r-- | 63.7 KB |
| lockref.c | -rw-r--r-- | 4.5 KB |
| logic_iomem.c | -rw-r--r-- | 7.1 KB |
| logic_pio.c | -rw-r--r-- | 8.5 KB |
| lru_cache.c | -rw-r--r-- | 18.8 KB |
| lshrdi3.c | -rw-r--r-- | 559 bytes |
| memcat_p.c | -rw-r--r-- | 753 bytes |
| memcpy_kunit.c | -rw-r--r-- | 8.0 KB |
| memory-notifier-error-inject.c | -rw-r--r-- | 1.1 KB |
| memregion.c | -rw-r--r-- | 429 bytes |
| memweight.c | -rw-r--r-- | 1.0 KB |
| muldi3.c | -rw-r--r-- | 1.7 KB |
| net_utils.c | -rw-r--r-- | 640 bytes |
| netdev-notifier-error-inject.c | -rw-r--r-- | 1.5 KB |
| nlattr.c | -rw-r--r-- | 26.9 KB |
| nmi_backtrace.c | -rw-r--r-- | 3.3 KB |
| nodemask.c | -rw-r--r-- | 653 bytes |
| notifier-error-inject.c | -rw-r--r-- | 2.5 KB |
| notifier-error-inject.h | -rw-r--r-- | 653 bytes |
| objagg.c | -rw-r--r-- | 28.3 KB |
| of-reconfig-notifier-error-inject.c | -rw-r--r-- | 1.3 KB |
| oid_registry.c | -rw-r--r-- | 4.4 KB |
| once.c | -rw-r--r-- | 1.5 KB |
| packing.c | -rw-r--r-- | 6.5 KB |
| parman.c | -rw-r--r-- | 10.6 KB |
| parser.c | -rw-r--r-- | 8.9 KB |
| pci_iomap.c | -rw-r--r-- | 5.7 KB |
| percpu-refcount.c | -rw-r--r-- | 15.3 KB |
| percpu_counter.c | -rw-r--r-- | 6.4 KB |
| percpu_test.c | -rw-r--r-- | 3.2 KB |
| plist.c | -rw-r--r-- | 5.9 KB |
| pm-notifier-error-inject.c | -rw-r--r-- | 1.2 KB |
| radix-tree.c | -rw-r--r-- | 43.1 KB |
| random32.c | -rw-r--r-- | 18.5 KB |
| ratelimit.c | -rw-r--r-- | 1.6 KB |
| rbtree.c | -rw-r--r-- | 17.1 KB |
| rbtree_test.c | -rw-r--r-- | 9.4 KB |
| refcount.c | -rw-r--r-- | 4.8 KB |
| rhashtable.c | -rw-r--r-- | 29.5 KB |
| sbitmap.c | -rw-r--r-- | 18.6 KB |
| scatterlist.c | -rw-r--r-- | 28.1 KB |
| seq_buf.c | -rw-r--r-- | 10.0 KB |
| sg_pool.c | -rw-r--r-- | 4.2 KB |
| sg_split.c | -rw-r--r-- | 5.0 KB |
| sha1.c | -rw-r--r-- | 6.3 KB |
| show_mem.c | -rw-r--r-- | 1.1 KB |
| siphash.c | -rw-r--r-- | 11.9 KB |
| slub_kunit.c | -rw-r--r-- | 3.3 KB |
| smp_processor_id.c | -rw-r--r-- | 1.4 KB |
| sort.c | -rw-r--r-- | 8.4 KB |
| stackdepot.c | -rw-r--r-- | 11.8 KB |
| stmp_device.c | -rw-r--r-- | 1.9 KB |
| string.c | -rw-r--r-- | 21.0 KB |
| string_helpers.c | -rw-r--r-- | 21.3 KB |
| strncpy_from_user.c | -rw-r--r-- | 3.9 KB |
| strnlen_user.c | -rw-r--r-- | 3.3 KB |
| syscall.c | -rw-r--r-- | 2.7 KB |
| test-kstrtox.c | -rw-r--r-- | 17.3 KB |
| test-string_helpers.c | -rw-r--r-- | 14.9 KB |
| test_bitmap.c | -rw-r--r-- | 27.8 KB |
| test_bitops.c | -rw-r--r-- | 2.5 KB |
| test_bits.c | -rw-r--r-- | 1.8 KB |
| test_blackhole_dev.c | -rw-r--r-- | 2.5 KB |
| test_bpf.c | -rw-r--r-- | 348.8 KB |
| test_debug_virtual.c | -rw-r--r-- | 981 bytes |
| test_firmware.c | -rw-r--r-- | 27.7 KB |
| test_fpu.c | -rw-r--r-- | 2.0 KB |
| test_free_pages.c | -rw-r--r-- | 995 bytes |
| test_hash.c | -rw-r--r-- | 6.3 KB |
| test_hexdump.c | -rw-r--r-- | 6.3 KB |
| test_hmm.c | -rw-r--r-- | 29.3 KB |
| test_hmm_uapi.h | -rw-r--r-- | 2.4 KB |
| test_ida.c | -rw-r--r-- | 4.3 KB |
| test_kasan.c | -rw-r--r-- | 31.1 KB |
| test_kasan_module.c | -rw-r--r-- | 3.3 KB |
| test_kmod.c | -rw-r--r-- | 29.9 KB |
| test_kprobes.c | -rw-r--r-- | 9.4 KB |
| test_linear_ranges.c | -rw-r--r-- | 7.5 KB |
| test_list_sort.c | -rw-r--r-- | 3.3 KB |
| test_lockup.c | -rw-r--r-- | 16.3 KB |
| test_memcat_p.c | -rw-r--r-- | 2.2 KB |
| test_meminit.c | -rw-r--r-- | 9.7 KB |
| test_min_heap.c | -rw-r--r-- | 4.3 KB |
| test_module.c | -rw-r--r-- | 794 bytes |
| test_objagg.c | -rw-r--r-- | 24.6 KB |
| test_overflow.c | -rw-r--r-- | 22.3 KB |
| test_parman.c | -rw-r--r-- | 11.2 KB |
| test_printf.c | -rw-r--r-- | 18.7 KB |
| test_rhashtable.c | -rw-r--r-- | 20.0 KB |
| test_scanf.c | -rw-r--r-- | 28.9 KB |
| test_siphash.c | -rw-r--r-- | 7.5 KB |
| test_sort.c | -rw-r--r-- | 907 bytes |
| test_stackinit.c | -rw-r--r-- | 15.2 KB |
| test_static_key_base.c | -rw-r--r-- | 1.6 KB |
| test_static_keys.c | -rw-r--r-- | 5.6 KB |
| test_string.c | -rw-r--r-- | 3.9 KB |
| test_strscpy.c | -rw-r--r-- | 4.0 KB |
| test_sysctl.c | -rw-r--r-- | 3.9 KB |
| test_ubsan.c | -rw-r--r-- | 2.9 KB |
| test_user_copy.c | -rw-r--r-- | 9.1 KB |
| test_uuid.c | -rw-r--r-- | 3.4 KB |
| test_vmalloc.c | -rw-r--r-- | 10.9 KB |
| test_xarray.c | -rw-r--r-- | 46.8 KB |
| textsearch.c | -rw-r--r-- | 9.3 KB |
| timerqueue.c | -rw-r--r-- | 2.3 KB |
| ts_bm.c | -rw-r--r-- | 5.1 KB |
| ts_fsm.c | -rw-r--r-- | 10.4 KB |
| ts_kmp.c | -rw-r--r-- | 4.1 KB |
| ubsan.c | -rw-r--r-- | 10.0 KB |
| ubsan.h | -rw-r--r-- | 1.8 KB |
| ucmpdi2.c | -rw-r--r-- | 568 bytes |
| ucs2_string.c | -rw-r--r-- | 2.5 KB |
| usercopy.c | -rw-r--r-- | 2.2 KB |
| uuid.c | -rw-r--r-- | 2.9 KB |
| vsprintf.c | -rw-r--r-- | 87.2 KB |
| win_minmax.c | -rw-r--r-- | 3.4 KB |
| xarray.c | -rw-r--r-- | 58.5 KB |
| xxhash.c | -rw-r--r-- | 12.7 KB |
Computing file changes ...
