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Ubuntu: (Multiple Advisories) (CVE-2024-26798): Linux kernel vulnerabilities

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Ubuntu: (Multiple Advisories) (CVE-2024-26798): Linux kernel vulnerabilities

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
04/04/2024
Created
07/02/2024
Added
07/01/2024
Modified
08/06/2024

Description

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+0x6f8/0x1570 drivers/tty/tty_io.c:2803 vfs_ioctl fs/ioctl.c:51 [inline] ... So restore the font data in any case, not only for user fonts. Note the later 'if' is now protected by 'old_userfont' and not 'old_data' as the latter is always set now. (And it is supposed to be non-NULL. Otherwise we would see the bug above again.)

Solution(s)

  • ubuntu-upgrade-linux-image-5-15-0-1030-xilinx-zynqmp
  • ubuntu-upgrade-linux-image-5-15-0-1046-gkeop
  • ubuntu-upgrade-linux-image-5-15-0-1056-ibm
  • ubuntu-upgrade-linux-image-5-15-0-1057-ibm
  • ubuntu-upgrade-linux-image-5-15-0-1058-intel-iotg
  • ubuntu-upgrade-linux-image-5-15-0-1058-nvidia
  • ubuntu-upgrade-linux-image-5-15-0-1058-nvidia-lowlatency
  • ubuntu-upgrade-linux-image-5-15-0-1058-raspi
  • ubuntu-upgrade-linux-image-5-15-0-1060-gke
  • ubuntu-upgrade-linux-image-5-15-0-1060-kvm
  • ubuntu-upgrade-linux-image-5-15-0-1061-oracle
  • ubuntu-upgrade-linux-image-5-15-0-1062-gcp
  • ubuntu-upgrade-linux-image-5-15-0-1063-aws
  • ubuntu-upgrade-linux-image-5-15-0-1065-azure-fde
  • ubuntu-upgrade-linux-image-5-15-0-1066-azure
  • ubuntu-upgrade-linux-image-5-15-0-110-lowlatency
  • ubuntu-upgrade-linux-image-5-15-0-110-lowlatency-64k
  • ubuntu-upgrade-linux-image-5-15-0-112-generic
  • ubuntu-upgrade-linux-image-5-15-0-112-generic-64k
  • ubuntu-upgrade-linux-image-5-15-0-112-generic-lpae
  • ubuntu-upgrade-linux-image-5-15-0-113-generic
  • ubuntu-upgrade-linux-image-5-15-0-113-generic-64k
  • ubuntu-upgrade-linux-image-5-15-0-113-generic-lpae
  • ubuntu-upgrade-linux-image-6-5-0-1017-starfive
  • ubuntu-upgrade-linux-image-6-5-0-1020-raspi
  • ubuntu-upgrade-linux-image-6-5-0-1023-aws
  • ubuntu-upgrade-linux-image-6-5-0-1023-nvidia
  • ubuntu-upgrade-linux-image-6-5-0-1023-nvidia-64k
  • ubuntu-upgrade-linux-image-6-5-0-1024-azure
  • ubuntu-upgrade-linux-image-6-5-0-1024-azure-fde
  • ubuntu-upgrade-linux-image-6-5-0-1024-gcp
  • ubuntu-upgrade-linux-image-6-5-0-1026-oracle
  • ubuntu-upgrade-linux-image-6-5-0-1026-oracle-64k
  • ubuntu-upgrade-linux-image-6-5-0-1027-oem
  • ubuntu-upgrade-linux-image-6-5-0-44-generic
  • ubuntu-upgrade-linux-image-6-5-0-44-generic-64k
  • ubuntu-upgrade-linux-image-6-5-0-44-lowlatency
  • ubuntu-upgrade-linux-image-6-5-0-44-lowlatency-64k
  • ubuntu-upgrade-linux-image-aws
  • ubuntu-upgrade-linux-image-aws-lts-22-04
  • ubuntu-upgrade-linux-image-azure
  • ubuntu-upgrade-linux-image-azure-fde
  • ubuntu-upgrade-linux-image-azure-fde-lts-22-04
  • ubuntu-upgrade-linux-image-azure-lts-22-04
  • ubuntu-upgrade-linux-image-gcp
  • ubuntu-upgrade-linux-image-gcp-lts-22-04
  • ubuntu-upgrade-linux-image-generic
  • ubuntu-upgrade-linux-image-generic-64k
  • ubuntu-upgrade-linux-image-generic-64k-hwe-20-04
  • ubuntu-upgrade-linux-image-generic-64k-hwe-22-04
  • ubuntu-upgrade-linux-image-generic-hwe-20-04
  • ubuntu-upgrade-linux-image-generic-hwe-22-04
  • ubuntu-upgrade-linux-image-generic-lpae
  • ubuntu-upgrade-linux-image-generic-lpae-hwe-20-04
  • ubuntu-upgrade-linux-image-gke
  • ubuntu-upgrade-linux-image-gke-5-15
  • ubuntu-upgrade-linux-image-gkeop
  • ubuntu-upgrade-linux-image-gkeop-5-15
  • ubuntu-upgrade-linux-image-ibm
  • ubuntu-upgrade-linux-image-intel
  • ubuntu-upgrade-linux-image-intel-iotg
  • ubuntu-upgrade-linux-image-kvm
  • ubuntu-upgrade-linux-image-lowlatency
  • ubuntu-upgrade-linux-image-lowlatency-64k
  • ubuntu-upgrade-linux-image-lowlatency-64k-hwe-20-04
  • ubuntu-upgrade-linux-image-lowlatency-64k-hwe-22-04
  • ubuntu-upgrade-linux-image-lowlatency-hwe-20-04
  • ubuntu-upgrade-linux-image-lowlatency-hwe-22-04
  • ubuntu-upgrade-linux-image-nvidia
  • ubuntu-upgrade-linux-image-nvidia-6-5
  • ubuntu-upgrade-linux-image-nvidia-64k-6-5
  • ubuntu-upgrade-linux-image-nvidia-64k-hwe-22-04
  • ubuntu-upgrade-linux-image-nvidia-hwe-22-04
  • ubuntu-upgrade-linux-image-nvidia-lowlatency
  • ubuntu-upgrade-linux-image-oem-20-04
  • ubuntu-upgrade-linux-image-oem-20-04b
  • ubuntu-upgrade-linux-image-oem-20-04c
  • ubuntu-upgrade-linux-image-oem-20-04d
  • ubuntu-upgrade-linux-image-oem-22-04
  • ubuntu-upgrade-linux-image-oem-22-04a
  • ubuntu-upgrade-linux-image-oem-22-04b
  • ubuntu-upgrade-linux-image-oem-22-04c
  • ubuntu-upgrade-linux-image-oem-22-04d
  • ubuntu-upgrade-linux-image-oracle
  • ubuntu-upgrade-linux-image-oracle-64k
  • ubuntu-upgrade-linux-image-oracle-lts-22-04
  • ubuntu-upgrade-linux-image-raspi
  • ubuntu-upgrade-linux-image-raspi-nolpae
  • ubuntu-upgrade-linux-image-starfive
  • ubuntu-upgrade-linux-image-virtual
  • ubuntu-upgrade-linux-image-virtual-hwe-20-04
  • ubuntu-upgrade-linux-image-virtual-hwe-22-04
  • ubuntu-upgrade-linux-image-xilinx-zynqmp

References

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