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Samasth Norway Ananda 4a4bac8695 fbcon: fix integer overflow in fbcon_do_set_font
commit 1a194e6c8e1ee745e914b0b7f50fa86c89ed13fe upstream.

Fix integer overflow vulnerabilities in fbcon_do_set_font() where font
size calculations could overflow when handling user-controlled font
parameters.

The vulnerabilities occur when:
1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount
   multiplication with user-controlled values that can overflow.
2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow
3. This results in smaller allocations than expected, leading to buffer
   overflows during font data copying.

Add explicit overflow checking using check_mul_overflow() and
check_add_overflow() kernel helpers to safety validate all size
calculations before allocation.

Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 39b3cffb8c ("fbcon: prevent user font height or width change from causing potential out-of-bounds access")
Cc: George Kennedy <george.kennedy@oracle.com>
Cc: stable <stable@vger.kernel.org>
Cc: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Shixiong Ou <oushixiong@kylinos.cn>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org> # v5.9+
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250912170023.3931881-1-samasth.norway.ananda@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-02 13:44:14 +02:00
arch arm64: dts: marvell: cn9132-clearfog: fix multi-lane pci x2 and x4 ports 2025-10-02 13:44:14 +02:00
block block: add a queue_limits_commit_update_frozen helper 2025-09-09 18:58:24 +02:00
certs
crypto crypto: af_alg - Set merge to zero early in af_alg_sendmsg 2025-09-25 11:13:49 +02:00
Documentation platform/x86: lg-laptop: Fix WMAB call in fan_mode_store() 2025-10-02 13:44:12 +02:00
drivers fbcon: fix integer overflow in fbcon_do_set_font 2025-10-02 13:44:14 +02:00
fs mm/hugetlb: fix folio is still mapped when deleted 2025-10-02 13:44:14 +02:00
include crypto: af_alg - Fix incorrect boolean values in af_alg_ctx 2025-10-02 13:44:13 +02:00
init io_uring: fix breakage in EXPERT menu 2025-08-15 12:13:32 +02:00
io_uring io_uring: fix incorrect io_kiocb reference in io_link_skb 2025-09-25 11:13:49 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel tracing: dynevent: Add a missing lockdown check on dynevent 2025-10-02 13:44:13 +02:00
lib lib/sbitmap: convert shallow_depth from one word to the whole sbitmap 2025-08-20 18:30:49 +02:00
LICENSES
mm kmsan: fix out-of-bounds access to shadow memory 2025-10-02 13:44:14 +02:00
net nexthop: Forbid FDB status change while nexthop is in a group 2025-10-02 13:44:10 +02:00
rust rust: alloc: fix rusttest by providing Cmalloc::aligned_layout too 2025-08-28 16:31:13 +02:00
samples ftrace/samples: Fix function size computation 2025-09-19 16:35:44 +02:00
scripts rust: support Rust >= 1.91.0 target spec 2025-09-09 18:58:22 +02:00
security apparmor: Fix 8-byte alignment for initial dfa blob streams 2025-08-28 16:30:56 +02:00
sound ALSA: usb-audio: Add mute TLV for playback volumes on more devices 2025-10-02 13:44:07 +02:00
tools selftests: fib_nexthops: Fix creation of non-FDB nexthops 2025-10-02 13:44:10 +02:00
usr
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-07-17 18:37:08 +02:00
.clang-format
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.49 2025-09-25 11:13:51 +02:00
README

Linux kernel

There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first.

In order to build the documentation, use make htmldocs or make pdfdocs. The formatted documentation can also be read online at:

https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory, several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.