CVE-2024-26798 — fbcon: always restore the old font data in fbcon_do_set_font()

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

fbcon: always restore the old font data in fbcon_do_set_font()

Commit a5a923038d70 (fbdev: fbcon: Properly revert changes when vc_resize() failed) started restoring old font data upon failure (of vc_resize()). But it performs so only for user fonts. It means that the "system"/internal fonts are not restored at all. So in result, the very first call to fbcon_do_set_font() performs no restore at all upon failing vc_resize().

This can be reproduced by Syzkaller to crash the system on the next invocation of font_get(). It's rather hard to hit the allocation failure in vc_resize() on the first font_set(), but not impossible. Esp. if fault injection is used to aid the execution/failure. It was demonstrated by Sirius: BUG: unable to handle page fault for address: fffffffffffffff8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD cb7b067 P4D cb7b067 PUD cb7d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8007 Comm: poc Not tainted 6.7.0-g9d1694dc91ce #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:fbcon_get_font+0x229/0x800 drivers/video/fbdev/core/fbcon.c:2286 Call Trace: <TASK> con_font_get drivers/tty/vt/vt.c:4558 [inline] con_font_op+0x1fc/0xf20 drivers/tty/vt/vt.c:4673 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x632/0x2ec0 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0…

USN-6820-1 — linux, linux-gcp, linux-gcp-5.15, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-xilinx-zynqmp vulnerabilities

Affected: Ubuntu:20.04:LTS: linux-gcp-5.15, Ubuntu:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-gcp, Ubuntu:22.04:LTS: linux-lowlatency, Ubuntu:22.04:LTS: linux-xilinx-zynqmp

It was discovered that the ATA over Ethernet (AoE) driver in the Linux kernel contained a race condition, leading to a use-after-free vulnerability. An attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2023-6270)

It was discovered that the Atheros 802.11ac wireless driver did not properly validate certain data structures, leading to a NULL pointer dereference. An attacker could possibly use this to cause a denial of service. (CVE-2023-7042)

It was discovered that the HugeTLB file system component of the Linux Kernel contained a NULL pointer dereference vulnerability. A privileged attacker could possibly use this to to cause a denial of service. (CVE-2024-0841)

It was discovered that the Intel Data Streaming and Intel Analytics Accelerator drivers in the Linux kernel allowed direct access to the devices for unprivileged users and virtual machines. A local attacker could use this to cause a denial of service. (CVE-2024-21823)

Yuxuan Hu discovered that the Bluetooth RFCOMM protocol driver in the Linux Kernel contained a race condition, leading to a NULL pointer dereference. An attacker could possibly use this to cause a denial of service (system crash). (CVE-2024-22099)

It was discovered that the MediaTek SoC Gigabit Ethernet driver in the Linux kernel contained a race condition when stopping the device. A local attacker could possibly use this to cause a denial of service (device unavailability). (CVE-2024-27432)

Several securi…

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CVE-2024-26798 — fbcon: always restore the old font data in fbcon_do_set_font()

USN-6820-1 — linux, linux-gcp, linux-gcp-5.15, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-xilinx-zynqmp vulnerabilities