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Mon, 22 Sep 2025 13:49:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id uN1KLdRT0WguAgAAD6G6ig (envelope-from ); Mon, 22 Sep 2025 13:49:08 +0000 From: Thomas Zimmermann To: jani.nikula@linux.intel.com, samasth.norway.ananda@oracle.com, simona@ffwll.ch, deller@gmx.de Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Thomas Zimmermann , George Kennedy , Greg Kroah-Hartman , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Sam Ravnborg , Qianqiang Liu , Shixiong Ou , Kees Cook , stable@vger.kernel.org, Zsolt Kajtar Subject: [PATCH] fbcon: Fix OOB access in font allocation Date: Mon, 22 Sep 2025 15:45:54 +0200 Message-ID: <20250922134619.257684-1-tzimmermann@suse.de> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-3.51 / 50.00]; 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RCVD_TLS_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,suse.de:dkim,suse.de:email,intel.com:email,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Spam-Flag: NO X-Spam-Level: X-Rspamd-Queue-Id: 349621F79A X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Score: -3.51 Commit 1a194e6c8e1e ("fbcon: fix integer overflow in fbcon_do_set_font") introduced an out-of-bounds access by storing data and allocation sizes in the same variable. Restore the old size calculation and use the new variable 'alloc_size' for the allocation. Signed-off-by: Thomas Zimmermann Fixes: 1a194e6c8e1e ("fbcon: fix integer overflow in fbcon_do_set_font") Reported-by: Jani Nikula Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15020 Cc: Samasth Norway Ananda Cc: Thomas Zimmermann Cc: George Kennedy Cc: Greg Kroah-Hartman Cc: Simona Vetter Cc: Helge Deller Cc: "Ville Syrjälä" Cc: Sam Ravnborg Cc: Qianqiang Liu Cc: Shixiong Ou Cc: Kees Cook Cc: # v5.9+ Cc: Zsolt Kajtar --- drivers/video/fbdev/core/fbcon.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 5fade44931b8..c1c0cdd7597c 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2518,7 +2518,7 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font, unsigned charcount = font->charcount; int w = font->width; int h = font->height; - int size; + int size, alloc_size; int i, csum; u8 *new_data, *data = font->data; int pitch = PITCH(font->width); @@ -2551,10 +2551,10 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font, return -EINVAL; /* Check for overflow in allocation size calculation */ - if (check_add_overflow(FONT_EXTRA_WORDS * sizeof(int), size, &size)) + if (check_add_overflow(FONT_EXTRA_WORDS * sizeof(int), size, &alloc_size)) return -EINVAL; - new_data = kmalloc(size, GFP_USER); + new_data = kmalloc(alloc_size, GFP_USER); if (!new_data) return -ENOMEM; -- 2.51.0