An information leakage issue was found in the way Linux kernel's KVM hypervisor handled page fault exception while emulating instructions like VMXON, VMCLEAR, VMPTRLD, VMWRITE with memory address as an operand. It occurs if the operand is an mmio address, as the returned exception object holds uninitialised stack memory contents.
A guest user/process could use this flaw to leak host's stack memory contents to a guest.
It affects only Intel processors and only when nested virtualization is enabled.
Upstream patch: --------------- -> https://git.kernel.org/linus/353c0956a618a07ba4bbe7ad00ff29fe70e8412a
Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/02/18/2
A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific Rregister(MSR) access with nested(=1) virtualization enabled. In that, L1 guest could access L0's APIC register values via L2 guest, when 'virtualize x2APIC mode' is enabled.
A guest could use this flaw to potentially crash the host kernel resulting in DoS issue.
Upstream patches: ----------------- -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=acff78477b9b4f26ecdf65733a4ed77fe837e9dc -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c73f4c998e1fd4249b9edfa39e23f4fda2b9b041
Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/04/08/1
A flaw was found in the Linux kernel's implementation of Logical Link Control and Adaptation Protocol (L2CAP), part of the Bluetooth stack. An attacker, within the range of standard Bluetooth transmissions, can create and send a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.
A flaw was found in the Linux kernel's implementation of logical link control and adaptation protocol (L2CAP), part of the Bluetooth stack in the l2capparseconfrsp and l2capparseconfreq functions. An attacker with physical access within the range of standard Bluetooth transmission can create a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.
A flaw was found in the Linux kernel's implementation of ext4 extent management. The kernel doesn't correctly initialize memory regions in the extent tree block which may be exported to a local user to obtain sensitive information by reading empty/uninitialized data from the filesystem.
A flaw was found in Linux kernel ext4 filesystem. A local user can cause an out-of-bound access in ext4getgroupinfo function and so a denial of service and a system crash by mounting and operating on a crafted ext4 filesystem image.
References:
https://bugzilla.kernel.org/showbug.cgi?id=200015
http://patchwork.ozlabs.org/patch/929792/
An upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6e8ab72a812396996035a37e5ca4b3b99b5d214b
A double free vulnerability was found in the vmwgfx driver in the Linux kernel. Quoting ZDI security advisory [1]:
"This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the handling of vmwbufferobject objects. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel."
[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20292/
========== 1. Null-ptr-deref in xfrmupdateaeparams() ==========
[require privilege]: CAPNETADMIN
[effects]: local DoS
[crash stack]: [ 47.933119] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 47.933119] #PF: supervisor write access in kernel mode [ 47.933119] #PF: errorcode(0x0002) - not-present page [ 47.933119] PGD 8253067 P4D 8253067 PUD 8e0e067 PMD 0 [ 47.933119] Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI [ 47.933119] CPU: 0 PID: 98 Comm: poc.npd Not tainted 6.4.0-rc7-00072-gdad9774deaf1 #8 [ 47.933119] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.o4 [ 47.933119] RIP: 0010:memcpyorig+0xad/0x140 [ 47.933119] Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c [ 47.933119] RSP: 0018:ffff888008f57658 EFLAGS: 00000202 [ 47.933119] RAX: 0000000000000000 RBX: ffff888008bd0000 RCX: ffffffff8238e571 [ 47.933119] RDX: 0000000000000018 RSI: ffff888007f64844 RDI: 0000000000000000 [ 47.933119] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 47.933119] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888008f57818 [ 47.933119] R13: ffff888007f64aa4 R14: 0000000000000000 R15: 0000000000000000 [ 47.933119] FS: 00000000014013c0(0000) GS:ffff88806d600000(0000) knlGS:0000000000000000 [ 47.933119] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 47.933119] CR2: 0000000000000000 CR3: 00000000054d8000 CR4: 00000000000006f0 [ 47.933119] Call Trace: [ 47.933119] <TASK> [ 47.933119] ? die+0x1f/0x70 [ 47.933119] ? pagefaultoops+0x1e8/0x500 [ 47.933119] ? pfxisprefetch.constprop.0+0x10/0x10 [ 47.933119] ? pfxpagefaultoops+0x10/0x10 [ 47.933119] ? rawspinunlockirqrestore+0x11/0x40 [ 47.933119] ? fixupexception+0x36/0x460 [ 47.933119] ? rawspinunlockirqrestore+0x11/0x40 [ 47.933119] ? excpagefault+0x5e/0xc0 [ 47.933119] ? asmexcpagefault+0x26/0x30 [ 47.933119] ? xfrmupdateaeparams+0xd1/0x260 [ 47.933119] ? memcpyorig+0xad/0x140 [ 47.933119] ? pfxrawspinlockbh+0x10/0x10 [ 47.933119] xfrmupdateaeparams+0xe7/0x260 [ 47.933119] xfrmnewae+0x298/0x4e0 [ 47.933119] ? pfxxfrmnewae+0x10/0x10 [ 47.933119] xfrmuserrcvmsg+0x25a/0x410 [ 47.933119] ? pfxxfrmuserrcvmsg+0x10/0x10 [ 47.933119] ? allocskb+0xcf/0x210 [ 47.933119] ? stacktracesave+0x90/0xd0 [ 47.933119] ? filterirqstacks+0x1c/0x70 [ 47.933119] ? stackdepotsave+0x39/0x4e0 [ 47.933119] ? kasanslabfree+0x10a/0x190 [ 47.933119] ? kmemcachefree+0x9c/0x340 [ 47.933119] ? netlinkrecvmsg+0x23c/0x660 [ 47.933119] ? sockrecvmsg+0xeb/0xf0 [ 47.933119] ? sysrecvfrom+0x13c/0x1f0 [ 47.933119] ? x64sysrecvfrom+0x71/0x90 [ 47.933119] ? dosyscall64+0x3f/0x90 [ 47.933119] ? entrySYSCALL64afterhwframe+0x72/0xdc [ 47.933119] ? copyout+0x3e/0x50 [ 47.933119] netlinkrcvskb+0xd6/0x210 [ 47.933119] ? pfxxfrmuserrcvmsg+0x10/0x10 [ 47.933119] ? pfxnetlinkrcvskb+0x10/0x10 [ 47.933119] ? pfxsockhasperm+0x10/0x10 [ 47.933119] ? mutexlock+0x8d/0xe0 [ 47.933119] ? pfxmutexlock+0x10/0x10 [ 47.933119] xfrmnetlinkrcv+0x44/0x50 [ 47.933119] netlinkunicast+0x36f/0x4c0 [ 47.933119] ? pfxnetlinkunicast+0x10/0x10 [ 47.933119] ? netlinkrecvmsg+0x500/0x660 [ 47.933119] netlinksendmsg+0x3b7/0x700 [ 47.933119] ? pfxnetlinksendmsg+0x10/0x10 [ 47.933119] ? updateloadavg+0x591/0xab0 [ 47.933119] ? pfxnetlinksendmsg+0x10/0x10 [ 47.933119] socksendmsg+0xde/0xe0 [ 47.933119] syssendto+0x18d/0x230 [ 47.933119] ? pfxsyssendto+0x10/0x10 [ 47.933119] ? rbinsertcolor+0x1c0/0x280 [ 47.933119] ? timerqueueadd+0x128/0x150 [ 47.933119] ? ktimeget+0x49/0xb0 [ 47.933119] ? pfxnativeapicmemwrite+0x10/0x10 [ 47.933119] ? lapicnextevent+0x35/0x40 [ 47.933119] ? clockeventsprogramevent+0xdf/0x140 [ 47.933119] ? hrtimerinterrupt+0x321/0x360 [ 47.933119] x64syssendto+0x71/0x90 [ 47.933119] dosyscall64+0x3f/0x90 [ 47.933119] entrySYSCALL64afterhwframe+0x72/0xdc [ 47.933119] RIP: 0033:0x44b8aa [ 47.933119] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 9 [ 47.933119] RSP: 002b:00007fff7ded8258 EFLAGS: 00000246 ORIGRAX: 000000000000002c [ 47.933119] RAX: ffffffffffffffda RBX: 00007fff7ded9688 RCX: 000000000044b8aa [ 47.933119] RDX: 00000000000002a8 RSI: 00007fff7ded8480 RDI: 0000000000000003 [ 47.933119] RBP: 00007fff7ded82c0 R08: 00007fff7ded829c R09: 000000000000000c [ 47.933119] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 47.933119] R13: 00007fff7ded9678 R14: 00000000004c37d0 R15: 0000000000000001 [ 47.933119] </TASK> [ 47.933119] Modules linked in: [ 47.933119] CR2: 0000000000000000 [ 47.933119] ---[ end trace 0000000000000000 ]--- [ 47.933119] RIP: 0010:memcpyorig+0xad/0x140 [ 47.933119] Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c [ 47.933119] RSP: 0018:ffff888008f57658 EFLAGS: 00000202 [ 47.933119] RAX: 0000000000000000 RBX: ffff888008bd0000 RCX: ffffffff8238e571 [ 47.933119] RDX: 0000000000000018 RSI: ffff888007f64844 RDI: 0000000000000000 [ 47.933119] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 47.933119] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888008f57818 [ 47.933119] R13: ffff888007f64aa4 R14: 0000000000000000 R15: 0000000000000000 [ 47.933119] FS: 00000000014013c0(0000) GS:ffff88806d600000(0000) knlGS:0000000000000000 [ 47.933119] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 47.933119] CR2: 0000000000000000 CR3: 00000000054d8000 CR4: 00000000000006f0 [ 47.933119] Kernel panic - not syncing: Fatal exception in interrupt [ 47.933119] Kernel Offset: disabled [ 47.933119] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
[buggy commit]: d8647b79c3b7 ("xfrm: Add user interface for esn and big anti-replay windows")
[root cause]: x->replayesn and x->preplayesn should be allocated at xfrmallocreplaystateesn(...) in xfrmstateconstruct(..), and then the xfrmupdateaeparams(...) is okay to update them. However, the current implementation allows a malicious user to directly dereference the pointer and crash the kernel like above.
[PoC code]: see attachment poc1.c. I have tested it in ubuntu 22.04 and latest Linux with QEMU.
[suggest fix]: Add NULL check in xfrmupdateaeparams() like below:
@@ -628,7 +628,7 @@ static void xfrmupdateaeparams(struct xfrmstate x, struct nlattr attrs, struct nlattr rt = attrs[XFRMAREPLAYTHRESH]; struct nlattr mt = attrs[XFRMAMTIMERTHRESH];
- if (re) { + if (re && x->replayesn && x->preplayesn) { struct xfrmreplaystateesn replayesn;
A use-after-free vulnerability was found in the siano smsusb module in the Linux kernel. The bug occurs during device initialization when the siano device is plugged in. This flaw allows a local user to crash the system, causing a denial of service condition.
A flaw was found in pfnswapentrytopage in memory management subsystem in the Linux Kernel. In this flaw, an attacker with a local user privilege may cause a denial of service problem due to a BUG statement referencing pmdt x.
A race condition vulnerability was found in the vmwgfx driver in the Linux kernel. Quoting ZDI security advisory [1]:
"This vulnerability allows local attackers to disclose sensitive information on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the handling of GEM objects. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to disclose information in the context of the kernel."
[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20110/
A flaw was found in the Linux kernel. Measuring usage of the shared memory does not scale with large shared memory segment counts which could lead to resource exhaustion and DoS.