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vuln-cve/data/2021/47xxx/CVE-2021-47531.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2021-47531",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2024-05-24T15:02:54.826Z",
"datePublished": "2024-05-24T15:09:41.360Z",
"dateUpdated": "2026-05-11T13:56:27.930Z"
},
"containers": {
"cna": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-05-11T13:56:27.930Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/msm: Fix mmap to include VM_IO and VM_DONTDUMP\n\nIn commit 510410bfc034 (\"drm/msm: Implement mmap as GEM object\nfunction\") we switched to a new/cleaner method of doing things. That's\ngood, but we missed a little bit.\n\nBefore that commit, we used to _first_ run through the\ndrm_gem_mmap_obj() case where `obj->funcs->mmap()` was NULL. That meant\nthat we ran:\n\n vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;\n vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));\n vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);\n\n...and _then_ we modified those mappings with our own. Now that\n`obj->funcs->mmap()` is no longer NULL we don't run the default\ncode. It looks like the fact that the vm_flags got VM_IO / VM_DONTDUMP\nwas important because we're now getting crashes on Chromebooks that\nuse ARC++ while logging out. Specifically a crash that looks like this\n(this is on a 5.10 kernel w/ relevant backports but also seen on a\n5.15 kernel):\n\n Unable to handle kernel paging request at virtual address ffffffc008000000\n Mem abort info:\n ESR = 0x96000006\n EC = 0x25: DABT (current EL), IL = 32 bits\n SET = 0, FnV = 0\n EA = 0, S1PTW = 0\n Data abort info:\n ISV = 0, ISS = 0x00000006\n CM = 0, WnR = 0\n swapper pgtable: 4k pages, 39-bit VAs, pgdp=000000008293d000\n [ffffffc008000000] pgd=00000001002b3003, p4d=00000001002b3003,\n pud=00000001002b3003, pmd=0000000000000000\n Internal error: Oops: 96000006 [#1] PREEMPT SMP\n [...]\n CPU: 7 PID: 15734 Comm: crash_dump64 Tainted: G W 5.10.67 #1 [...]\n Hardware name: Qualcomm Technologies, Inc. sc7280 IDP SKU2 platform (DT)\n pstate: 80400009 (Nzcv daif +PAN -UAO -TCO BTYPE=--)\n pc : __arch_copy_to_user+0xc0/0x30c\n lr : copyout+0xac/0x14c\n [...]\n Call trace:\n __arch_copy_to_user+0xc0/0x30c\n copy_page_to_iter+0x1a0/0x294\n process_vm_rw_core+0x240/0x408\n process_vm_rw+0x110/0x16c\n __arm64_sys_process_vm_readv+0x30/0x3c\n el0_svc_common+0xf8/0x250\n do_el0_svc+0x30/0x80\n el0_svc+0x10/0x1c\n el0_sync_handler+0x78/0x108\n el0_sync+0x184/0x1c0\n Code: f8408423 f80008c3 910020c6 36100082 (b8404423)\n\nLet's add the two flags back in.\n\nWhile we're at it, the fact that we aren't running the default means\nthat we _don't_ need to clear out VM_PFNMAP, so remove that and save\nan instruction.\n\nNOTE: it was confirmed that VM_IO was the important flag to fix the\nproblem I was seeing, but adding back VM_DONTDUMP seems like a sane\nthing to do so I'm doing that too."
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/gpu/drm/msm/msm_gem.c"
],
"versions": [
{
"version": "510410bfc034c57cc3caf1572aa47c1017bab2f9",
"lessThan": "8e2b7fe5e8a4be5e571561d9afcfbd92097288ba",
"status": "affected",
"versionType": "git"
},
{
"version": "510410bfc034c57cc3caf1572aa47c1017bab2f9",
"lessThan": "3466d9e217b337bf473ee629c608e53f9f3ab786",
"status": "affected",
"versionType": "git"
}
]
},
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"product": "Linux",
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"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/gpu/drm/msm/msm_gem.c"
],
"versions": [
{
"version": "5.15",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.15",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.15.7",
"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": [
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"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.15",
"versionEndExcluding": "5.15.7"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.15",
"versionEndExcluding": "5.16"
}
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"references": [
{
"url": "https://git.kernel.org/stable/c/8e2b7fe5e8a4be5e571561d9afcfbd92097288ba"
},
{
"url": "https://git.kernel.org/stable/c/3466d9e217b337bf473ee629c608e53f9f3ab786"
}
],
"title": "drm/msm: Fix mmap to include VM_IO and VM_DONTDUMP",
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"dateUpdated": "2024-08-04T05:39:59.773Z"
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"title": "CVE Program Container",
"references": [
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"url": "https://git.kernel.org/stable/c/8e2b7fe5e8a4be5e571561d9afcfbd92097288ba",
"tags": [
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"content": {
"id": "CVE-2021-47531",
"role": "CISA Coordinator",
"options": [
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"Exploitation": "none"
},
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"Automatable": "no"
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{
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"version": "2.0.3",
"timestamp": "2024-09-10T15:35:23.631797Z"
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