Affected: Alpaquita:stream: linux-lts
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix pointer-leak due to insufficient speculative store bypass mitigation
To mitigate Spectre v4, 2039f26f3aca ("bpf: Fix leakage due to insufficient speculative store bypass mitigation") inserts lfence instructions after 1) initializing a stack slot and 2) spilling a pointer to the stack.
However, this does not cover cases where a stack slot is first initialized with a pointer (subject to sanitization) but then overwritten with a scalar (not subject to sanitization because the slot was already initialized). In this case, the second write may be subject to speculative store bypass (SSB) creating a speculative pointer-as-scalar type confusion. This allows the program to subsequently leak the numerical pointer value using, for example, a branch-based cache side channel.
To fix this, also sanitize scalars if they write a stack slot that previously contained a pointer. Assuming that pointer-spills are only generated by LLVM on register-pressure, the performance impact on most real-world BPF programs should be small.
The following unprivileged BPF bytecode drafts a minimal exploit and the mitigation:
[...] // r6 = 0 or 1 (skalar, unknown user input) // r7 = accessible ptr for side channel // r10 = frame pointer (fp), to be leaked // r9 = r10 # fp alias to encourage ssb *(u64 *)(r9 - 8) = r10 // fp[-8] = ptr, to be leaked // lfence added here because of pointer spill to stack. // // O…
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix pointer-leak due to insufficient speculative store bypass mitigation
To mitigate Spectre v4, 2039f26f3aca ("bpf: Fix leakage due to insufficient speculative store bypass mitigation") inserts lfence instructions after 1) initializing a stack slot and 2) spilling a pointer to the stack.
However, this does not cover cases where a stack slot is first initialized with a pointer (subject to sanitization) but then overwritten with a scalar (not subject to sanitization because the slot was already initialized). In this case, the second write may be subject to speculative store bypass (SSB) creating a speculative pointer-as-scalar type confusion. This allows the program to subsequently leak the numerical pointer value using, for example, a branch-based cache side channel.
To fix this, also sanitize scalars if they write a stack slot that previously contained a pointer. Assuming that pointer-spills are only generated by LLVM on register-pressure, the performance impact on most real-world BPF programs should be small.
The following unprivileged BPF bytecode drafts a minimal exploit and the mitigation:
[...] // r6 = 0 or 1 (skalar, unknown user input) // r7 = accessible ptr for side channel // r10 = frame pointer (fp), to be leaked // r9 = r10 # fp alias to encourage ssb *(u64 *)(r9 - 8) = r10 // fp[-8] = ptr, to be leaked // lfence added here because of pointer spill to stack. // // O…
Affected: openEuler:20.03-LTS-SP4: kernel
The Linux Kernel, the operating system core itself. Security Fix(es):
In the Linux kernel, the following vulnerability has been resolved:
nfc: nci: add flush_workqueue to prevent uaf
Our detector found a concurrent use-after-free bug when detaching an NCI device. The main reason for this bug is the unexpected scheduling between the used delayed mechanism (timer and workqueue).
The race can be demonstrated below:
Thread-1 Thread-2 | nci_dev_up() | nci_open_device() | __nci_request(nci_reset_req) | nci_send_cmd | queue_work(cmd_work) nci_unregister_device() | nci_close_device() | ... del_timer_sync(cmd_timer)[1] | ... | Worker nci_free_device() | nci_cmd_work() kfree(ndev)[3] | mod_timer(cmd_timer)[2]
In short, the cleanup routine thought that the cmd_timer has already been detached by [1] but the mod_timer can re-attach the timer [2], even it is already released [3], resulting in UAF.
This UAF is easy to trigger, crash trace by POC is like below
[ 66.703713] ================================================================== [ 66.703974] BUG: KASAN: use-after-free in enqueue_timer+0x448/0x490 [ 66.703974] Write of size 8 at addr ffff888009fb7058 by task kworker/u4…
kernel: seg6: fix the iif in the IPv6 socket control block Kernel: race when faulting a device private page in memory manager kernel: use-after-free in l1oip timer handlers kernel: Rate limit overflow messages in r8152 in intr_callback kernel: vmwgfx: use-after-free in vmw_cmd_res_check kernel: vmwgfx: use-after-free in vmw_execbuf_tie_context hw: Intel: Gather Data Sampling (GDS) side channel vulnerability kernel: Information leak in l2cap_parse_conf_req in net/bluetooth/l2cap_core.c kernel: perf: Fix perf_pending_task() UaF kernel: gpiolib: fix memory leak in gpiochip_setup_dev() kernel: memcg: fix possible use-after-free in memcg_write_event_control() kernel: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths kernel: char: tpm: Protect tpm_pm_suspend with locks kernel: ixgbevf: Fix resource leak in ixgbevf_init_module() kernel: dax: make sure inodes are flushed before destroy cache kernel: watch_queue: Actually free the watch kernel: watch_queue: Fix NULL dereference in error cleanup kernel: rtc: pl031: fix rtc features null pointer dereference kernel: tpm: fix reference counting for struct tpm_chip kernel: NFSv4: Don't hold the layoutget locks across multiple RPC calls kernel: xprtrdma: treat all calls not a bcall when bc_serv is NULL kernel: net: ipv6: unexport __init-annotated seg6_hmac_init() kernel: af_unix: Fix a data-race in unix_dgram_peer_wake_me(). kernel: regulator: scmi: Fix refcount leak in scmi_regulator_probe kernel: mm/mempolicy: fix uninit-v…
Security update for the Linux Kernel
Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-gcp-5.4, Ubuntu:18.04:LTS: linux-hwe-5.4, Ubuntu:18.04:LTS: linux-ibm-5.4, Ubuntu:18.04:LTS: linux-oracle-5.4, Ubuntu:18.04:LTS: linux-raspi-5.4, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3 and 117 more
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix pointer-leak due to insufficient speculative store bypass mitigation To mitigate Spectre v4, 2039f26f3aca ("bpf: Fix leakage due to insufficient speculative store bypass mitigation") inserts lfence instructions after 1) initializing a stack slot and 2) spilling a pointer to the stack. However, this does not cover cases where a stack slot is first initialized with a pointer (subject to sanitization) but then overwritten with a scalar (not subject to sanitization because the slot was already initialized). In this case, the second write may be subject to speculative store bypass (SSB) creating a speculative pointer-as-scalar type confusion. This allows the program to subsequently leak the numerical pointer value using, for example, a branch-based cache side channel. To fix this, also sanitize scalars if they write a stack slot that previously contained a pointer. Assuming that pointer-spills are only generated by LLVM on register-pressure, the performance impact on most real-world BPF programs should be small. The following unprivileged BPF bytecode drafts a minimal exploit and the mitigation: [...] // r6 = 0 or 1 (skalar, unknown user input) // r7 = accessible ptr for side channel // r10 = frame pointer (fp), to be leaked // r9 = r10 # fp alias to encourage ssb *(u64 *)(r9 - 8) = r10 // fp[-8] = ptr, to be leaked // lfence added here because of pointer spill to stack. // // Ommitte…
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen oder nicht spezifizierte Effekte zu erzielen.