| { |
| "containers": { |
| "cna": { |
| "providerMetadata": { |
| "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" |
| }, |
| "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" |
| } |
| ] |
| }, |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "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": [ |
| { |
| "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" |
| } |
| ] |
| } |
| ] |
| } |
| ], |
| "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", |
| "x_generator": { |
| "engine": "bippy-1.2.0" |
| } |
| } |
| }, |
| "cveMetadata": { |
| "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", |
| "cveID": "CVE-2021-47531", |
| "requesterUserId": "gregkh@kernel.org", |
| "serial": "1", |
| "state": "PUBLISHED" |
| }, |
| "dataType": "CVE_RECORD", |
| "dataVersion": "5.0" |
| } |
