CVE-2022-49947

{"id": "CVE-2022-49947", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2025-06-18T11:15:21.717", "references": [{"url": "https://git.kernel.org/stable/c/1da52815d5f1b654c89044db0cdc6adce43da1f1", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/81203ab7a6ef843a2b904a0a494f28c457d44d27", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b2a97babb0a510f8921891f9e70c5a5ef33cadac", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinder: fix alloc->vma_vm_mm null-ptr dereference\n\nSyzbot reported a couple issues introduced by commit 44e602b4e52f\n(\"binder_alloc: add missing mmap_lock calls when using the VMA\"), in\nwhich we attempt to acquire the mmap_lock when alloc->vma_vm_mm has not\nbeen initialized yet.\n\nThis can happen if a binder_proc receives a transaction without having\npreviously called mmap() to setup the binder_proc->alloc space in [1].\nAlso, a similar issue occurs via binder_alloc_print_pages() when we try\nto dump the debugfs binder stats file in [2].\n\nSample of syzbot's crash report:\n ==================================================================\n KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]\n CPU: 0 PID: 3755 Comm: syz-executor229 Not tainted 6.0.0-rc1-next-20220819-syzkaller #0\n syz-executor229[3755] cmdline: ./syz-executor2294415195\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022\n RIP: 0010:__lock_acquire+0xd83/0x56d0 kernel/locking/lockdep.c:4923\n [...]\n Call Trace:\n <TASK>\n lock_acquire kernel/locking/lockdep.c:5666 [inline]\n lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631\n down_read+0x98/0x450 kernel/locking/rwsem.c:1499\n mmap_read_lock include/linux/mmap_lock.h:117 [inline]\n binder_alloc_new_buf_locked drivers/android/binder_alloc.c:405 [inline]\n binder_alloc_new_buf+0xa5/0x19e0 drivers/android/binder_alloc.c:593\n binder_transaction+0x242e/0x9a80 drivers/android/binder.c:3199\n binder_thread_write+0x664/0x3220 drivers/android/binder.c:3986\n binder_ioctl_write_read drivers/android/binder.c:5036 [inline]\n binder_ioctl+0x3470/0x6d00 drivers/android/binder.c:5323\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:870 [inline]\n __se_sys_ioctl fs/ioctl.c:856 [inline]\n __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n [...]\n ==================================================================\n\nFix these issues by setting up alloc->vma_vm_mm pointer during open()\nand caching directly from current->mm. This guarantees we have a valid\nreference to take the mmap_lock during scenarios described above.\n\n[1] https://syzkaller.appspot.com/bug?extid=f7dc54e5be28950ac459\n[2] https://syzkaller.appspot.com/bug?extid=a75ebe0452711c9e56d9"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: binder: correcci\u00f3n de la desreferencia alloc-&gt;vma_vm_mm null-ptr. Syzbot inform\u00f3 de un par de problemas introducidos por el commit 44e602b4e52f (\"binder_alloc: a\u00f1adir llamadas mmap_lock faltantes al usar la VMA\"), en el que se intenta adquirir mmap_lock cuando alloc-&gt;vma_vm_mm a\u00fan no se ha inicializado. Esto puede ocurrir si un binder_proc recibe una transacci\u00f3n sin haber llamado previamente a mmap() para configurar el espacio binder_proc-&gt;alloc en [1]. Adem\u00e1s, se produce un problema similar mediante binder_alloc_print_pages() al intentar volcar el archivo de estad\u00edsticas de binder debugfs en [2]. Ejemplo de informe de fallos de syzbot: ======================================================================= KASAN: null-ptr-deref en el rango [0x0000000000000128-0x000000000000012f] CPU: 0 PID: 3755 Comm: syz-executor229 No contaminado 6.0.0-rc1-next-20220819-syzkaller #0 syz-executor229[3755] cmdline: ./syz-executor2294415195 Nombre del hardware: Google Google Compute Engine/Google Compute Motor, BIOS Google 22/07/2022 RIP: 0010:__lock_acquire+0xd83/0x56d0 kernel/locking/lockdep.c:4923 [...] Rastreo de llamadas: lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 down_read+0x98/0x450 kernel/locking/rwsem.c:1499 mmap_read_lock include/linux/mmap_lock.h:117 [inline] binder_alloc_new_buf_locked drivers/android/binder_alloc.c:405 [inline] binder_alloc_new_buf+0xa5/0x19e0 drivers/android/binder_alloc.c:593 binder_transaction+0x242e/0x9a80 drivers/android/binder.c:3199 binder_thread_write+0x664/0x3220 drivers/android/binder.c:3986 binder_ioctl_write_read drivers/android/binder.c:5036 [inline] binder_ioctl+0x3470/0x6d00 drivers/android/binder.c:5323 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] ================================================================== Solucione estos problemas configurando el puntero alloc-&gt;vma_vm_mm durante la operaci\u00f3n open() y almacenando en cach\u00e9 directamente desde current-&gt;mm. Esto garantiza una referencia v\u00e1lida para tomar mmap_lock en los escenarios descritos anteriormente.. [1] https://syzkaller.appspot.com/bug?extid=f7dc54e5be28950ac459 [2] https://syzkaller.appspot.com/bug?extid=a75ebe0452711c9e56d9 "}], "lastModified": "2025-11-14T19:49:08.323", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AFA270B6-87DD-454A-97BB-682BF1119BD5", "versionEndExcluding": "5.15.66", "versionStartIncluding": "5.15.64"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3376C1D6-76B6-4B98-A217-1B9FD4E5D55B", "versionEndExcluding": "5.19.8", "versionStartIncluding": "5.19.6"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.0:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A46498B3-78E1-4623-AAE1-94D29A42BE4E"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}