Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:EOL][EOL]fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var[EOL][EOL]If fb_add_videomode() in fb_set_var() fails to allocate memory for[EOL]fb_videomode, later it may lead to a null-ptr dereference in[EOL]fb_videomode_to_var(), as the fb_info is registered while not having the[EOL]mode in modelist that is expected to be there, i.e. the one that is[EOL]described in fb_info->var.[EOL][EOL]================================================================[EOL]general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI[EOL]KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f][EOL]CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0[EOL]Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014[EOL]RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901[EOL]Call Trace:[EOL] display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929[EOL] fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071[EOL] resize_screen drivers/tty/vt/vt.c:1176 [inline][EOL] vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263[EOL] fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720[EOL] fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776[EOL] do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128[EOL] fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203[EOL] vfs_ioctl fs/ioctl.c:48 [inline][EOL] __do_sys_ioctl fs/ioctl.c:753 [inline][EOL] __se_sys_ioctl fs/ioctl.c:739 [inline][EOL] __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739[EOL] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46[EOL] entry_SYSCALL_64_after_hwframe+0x67/0xd1[EOL]================================================================[EOL][EOL]The reason is that fb_info->var is being modified in fb_set_var(), and[EOL]then fb_videomode_to_var() is called. If it fails to add the mode to[EOL]fb_info->modelist, fb_set_var() returns error, but does not restore the[EOL]old value of fb_info->var. Restore fb_info->var on failure the same way[EOL]it is done earlier in the function.[EOL][EOL]Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

CREATE(Triage):(User=admin) [CVE-2025-38214 (https://nvd.nist.gov/vuln/detail/CVE-2025-38214)