{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2021-47566","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-05-24T15:11:00.728Z","datePublished":"2024-05-24T15:12:53.432Z","dateUpdated":"2025-05-04T07:13:47.049Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2025-05-04T07:13:47.049Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nproc/vmcore: fix clearing user buffer by properly using clear_user()\n\nTo clear a user buffer we cannot simply use memset, we have to use\nclear_user().  With a virtio-mem device that registers a vmcore_cb and\nhas some logically unplugged memory inside an added Linux memory block,\nI can easily trigger a BUG by copying the vmcore via \"cp\":\n\n  systemd[1]: Starting Kdump Vmcore Save Service...\n  kdump[420]: Kdump is using the default log level(3).\n  kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\n  kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\n  kdump[465]: saving vmcore-dmesg.txt complete\n  kdump[467]: saving vmcore\n  BUG: unable to handle page fault for address: 00007f2374e01000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0003) - permissions violation\n  PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867\n  Oops: 0003 [#1] PREEMPT SMP NOPTI\n  CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86\n  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\n  RSP: 0018:ffffc9000073be08 EFLAGS: 00010212\n  RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000\n  RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008\n  RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50\n  R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000\n  R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8\n  FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0\n  Call Trace:\n   read_vmcore+0x236/0x2c0\n   proc_reg_read+0x55/0xa0\n   vfs_read+0x95/0x190\n   ksys_read+0x4f/0xc0\n   do_syscall_64+0x3b/0x90\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nSome x86-64 CPUs have a CPU feature called \"Supervisor Mode Access\nPrevention (SMAP)\", which is used to detect wrong access from the kernel\nto user buffers like this: SMAP triggers a permissions violation on\nwrong access.  In the x86-64 variant of clear_user(), SMAP is properly\nhandled via clac()+stac().\n\nTo fix, properly use clear_user() when we're dealing with a user buffer."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/vmcore.c"],"versions":[{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"a9e164bd160be8cbee1df70acb379129e3cd2e7c","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"33a7d698f30fa0b99d50569e9909d3baa65d8f6a","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"99d348b82bcb36171f24411d3f1a15706a2a937a","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"9ef384ed300d1bcfb23d0ab0b487d544444d4b52","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"fd7974c547abfb03072a4ee706d3a6f182266f89","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"a8a917058faf4abaec9fb614bb6d5f8fe3529ec6","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1","status":"affected","versionType":"git"},{"version":"997c136f518c5debd63847e78e2a8694f56dcf90","lessThan":"c1e63117711977cc4295b2ce73de29dd17066c82","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/vmcore.c"],"versions":[{"version":"3.0","status":"affected"},{"version":"0","lessThan":"3.0","status":"unaffected","versionType":"semver"},{"version":"4.4.294","lessThanOrEqual":"4.4.*","status":"unaffected","versionType":"semver"},{"version":"4.9.292","lessThanOrEqual":"4.9.*","status":"unaffected","versionType":"semver"},{"version":"4.14.257","lessThanOrEqual":"4.14.*","status":"unaffected","versionType":"semver"},{"version":"4.19.219","lessThanOrEqual":"4.19.*","status":"unaffected","versionType":"semver"},{"version":"5.4.163","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.83","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.6","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"5.16","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"4.4.294"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"4.9.292"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"4.14.257"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"4.19.219"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.4.163"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.10.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.15.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.0","versionEndExcluding":"5.16"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c"},{"url":"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a"},{"url":"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a"},{"url":"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52"},{"url":"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89"},{"url":"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6"},{"url":"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1"},{"url":"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82"}],"title":"proc/vmcore: 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