CVSS: -EPSS: 0%CPEs: 2EXPL: 0CVE-2021-47092 – KVM: VMX: Always clear vmx->fail on emulation_required
https://notcve.org/view.php?id=CVE-2021-47092
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Always clear vmx->fail on emulation_required Revert a relatively recent change that set vmx->fail if the vCPU is in L2 and emulation_required is true, as that behavior is completely bogus. Setting vmx->fail and synthesizing a VM-Exit is contradictory and wrong: (a) it's impossible to have both a VM-Fail and VM-Exit (b) vmcs.EXIT_REASON is not modified on VM-Fail (c) emulation_required refers to guest state and guest state checks are always VM-Exits, not VM-Fails. For KVM specifically, emulation_required is handled before nested exits in __vmx_handle_exit(), thus setting vmx->fail has no immediate effect, i.e. KVM calls into handle_invalid_guest_state() and vmx->fail is ignored. Setting vmx->fail can ultimately result in a WARN in nested_vmx_vmexit() firing when tearing down the VM as KVM never expects vmx->fail to be set when L2 is active, KVM always reflects those errors into L1. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 21158 at arch/x86/kvm/vmx/nested.c:4548 nested_vmx_vmexit+0x16bd/0x17e0 arch/x86/kvm/vmx/nested.c:4547 Modules linked in: CPU: 0 PID: 21158 Comm: syz-executor.1 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:nested_vmx_vmexit+0x16bd/0x17e0 arch/x86/kvm/vmx/nested.c:4547 Code: <0f> 0b e9 2e f8 ff ff e8 57 b3 5d 00 0f 0b e9 00 f1 ff ff 89 e9 80 Call Trace: vmx_leave_nested arch/x86/kvm/vmx/nested.c:6220 [inline] nested_vmx_free_vcpu+0x83/0xc0 arch/x86/kvm/vmx/nested.c:330 vmx_free_vcpu+0x11f/0x2a0 arch/x86/kvm/vmx/vmx.c:6799 kvm_arch_vcpu_destroy+0x6b/0x240 arch/x86/kvm/x86.c:10989 kvm_vcpu_destroy+0x29/0x90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 kvm_free_vcpus arch/x86/kvm/x86.c:11426 [inline] kvm_arch_destroy_vm+0x3ef/0x6b0 arch/x86/kvm/x86.c:11545 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1189 [inline] kvm_put_kvm+0x751/0xe40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1220 kvm_vcpu_release+0x53/0x60 arch/x86/kvm/../../.. • https://git.kernel.org/stable/c/c8607e4a086fae05efe5bffb47c5199c65e7216e https://git.kernel.org/stable/c/e4e4e7cb229821cd215031abc47efdab5486a67c https://git.kernel.org/stable/c/a80dfc025924024d2c61a4c1b8ef62b2fce76a04 •
CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2021-47091 – mac80211: fix locking in ieee80211_start_ap error path
https://notcve.org/view.php?id=CVE-2021-47091
In the Linux kernel, the following vulnerability has been resolved: mac80211: fix locking in ieee80211_start_ap error path We need to hold the local->mtx to release the channel context, as even encoded by the lockdep_assert_held() there. Fix it. En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mac80211: corrige el bloqueo en la ruta de error ieee80211_start_ap Necesitamos mantener local->mtx para liberar el contexto del canal, incluso codificado por lockdep_assert_held() allí. Arreglalo. • https://git.kernel.org/stable/c/295b02c4be74bebf988593b8322369513fcecf68 https://git.kernel.org/stable/c/ac61b9c6c0549aaeb98194cf429d93c41bfe5f79 https://git.kernel.org/stable/c/c1d1ec4db5f7264cfc21993e59e8f2dcecf4b44f https://git.kernel.org/stable/c/87a270625a89fc841f1a7e21aae6176543d8385c •
CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2021-47090 – mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page()
https://notcve.org/view.php?id=CVE-2021-47090
In the Linux kernel, the following vulnerability has been resolved: mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() Hulk Robot reported a panic in put_page_testzero() when testing madvise() with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt is not increased. page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:737! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: release_pages+0x53f/0x840 Call Trace: free_pages_and_swap_cache+0x64/0x80 tlb_flush_mmu+0x6f/0x220 unmap_page_range+0xe6c/0x12c0 unmap_single_vma+0x90/0x170 unmap_vmas+0xc4/0x180 exit_mmap+0xde/0x3a0 mmput+0xa3/0x250 do_exit+0x564/0x1470 do_group_exit+0x3b/0x100 __do_sys_exit_group+0x13/0x20 __x64_sys_exit_group+0x16/0x20 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: ---[ end trace e99579b570fe0649 ]--- RIP: 0010:release_pages+0x53f/0x840 En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mm/hwpoison: borre MF_COUNT_INCREASED antes de volver a intentar get_any_page() Hulk Robot informó un pánico en put_page_testzero() al probar madvise() con MADV_SOFT_OFFLINE. El ERROR() se activa al volver a intentar get_any_page(). • https://git.kernel.org/stable/c/b94e02822debdf0cc473556aad7dcc859f216653 https://git.kernel.org/stable/c/1f207076740101fed87074a6bc924dbe806f08a5 https://git.kernel.org/stable/c/c691e7575eff76e563b0199c23ec46bd454f43e3 https://git.kernel.org/stable/c/2a57d83c78f889bf3f54eede908d0643c40d5418 •
CVSS: -EPSS: 0%CPEs: 2EXPL: 0CVE-2021-47089 – kfence: fix memory leak when cat kfence objects
https://notcve.org/view.php?id=CVE-2021-47089
In the Linux kernel, the following vulnerability has been resolved: kfence: fix memory leak when cat kfence objects Hulk robot reported a kmemleak problem: unreferenced object 0xffff93d1d8cc02e8 (size 248): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 unreferenced object 0xffff93d419854000 (size 4096): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12- backtrace: seq_read_iter+0x313/0x440 seq_read+0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 I find that we can easily reproduce this problem with the following commands: cat /sys/kernel/debug/kfence/objects echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak The leaked memory is allocated in the stack below: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---> alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse ---> alloc seq_buf And it should have been released in the following process: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---> free here However, the release function corresponding to file_operations is not implemented in kfence. As a result, a memory leak occurs. Therefore, the solution to this problem is to implement the corresponding release function. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kfence: repara la pérdida de memoria cuando los objetos cat kfence Hulk robot informó un problema kmemleak: objeto sin referencia 0xffff93d1d8cc02e8 (tamaño 248): comm "cat", pid 23327, jiffies 4624670141 (edad 495992.217s ) volcado hexadecimal (primeros 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................. rastreo inverso: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 objeto sin referencia 0xffff93d419854000 (tamaño 4096): comm "cat", pid 23327, Jiffies 4624670141 (edad 495992,217 s) volcado hexadecimal (primeros 32 bytes) : 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda1 2- rastreo inverso: seq_read_iter+0x313/0x440 seq_read+ 0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Creo que podemos reproducir fácilmente este problema con los siguientes comandos: cat /sys/kernel/ depurar/ kfence/objects echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak La memoria filtrada se asigna en la pila siguiente: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---> alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse - --> alloc seq_buf Y debería haberse liberado en el siguiente proceso: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---> free aquí Sin embargo, la función de liberación correspondiente a file_operatives no está implementada en kfence. Como resultado, se produce una pérdida de memoria. • https://git.kernel.org/stable/c/0ce20dd840897b12ae70869c69f1ba34d6d16965 https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48 https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634 •
CVSS: -EPSS: 0%CPEs: 2EXPL: 0CVE-2021-47088 – mm/damon/dbgfs: protect targets destructions with kdamond_lock
https://notcve.org/view.php?id=CVE-2021-47088
In the Linux kernel, the following vulnerability has been resolved: mm/damon/dbgfs: protect targets destructions with kdamond_lock DAMON debugfs interface iterates current monitoring targets in 'dbgfs_target_ids_read()' while holding the corresponding 'kdamond_lock'. However, it also destructs the monitoring targets in 'dbgfs_before_terminate()' without holding the lock. This can result in a use_after_free bug. This commit avoids the race by protecting the destruction with the corresponding 'kdamond_lock'. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm/damon/dbgfs: protege las destrucciones de objetivos con kdamond_lock La interfaz DAMON debugfs itera los objetivos de monitoreo actuales en 'dbgfs_target_ids_read()' mientras mantiene el correspondiente 'kdamond_lock'. • https://git.kernel.org/stable/c/4bc05954d0076655cfaf6f0135585bdc20cd6b11 https://git.kernel.org/stable/c/330c6117a82c16a9a365a51cec5c9ab30b13245c https://git.kernel.org/stable/c/34796417964b8d0aef45a99cf6c2d20cebe33733 •