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([94.73.37.161]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38dd49d2cafsm11400302f8f.16.2025.02.12.00.49.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Feb 2025 00:49:17 -0800 (PST) From: =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= To: louis.chauvet@bootlin.com Cc: hamohammed.sa@gmail.com, simona@ffwll.ch, melissa.srw@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, danvet.vetter@ffwl.ch, sylphrenadin@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= Subject: [PATCH] drm/vkms: Fix use after free and double free on init error Date: Wed, 12 Feb 2025 09:49:12 +0100 Message-ID: <20250212084912.3196-1-jose.exposito89@gmail.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable If the driver initialization fails, the vkms_exit() function might access an uninitialized or freed default_config pointer and it might double free it. Fix both possible errors by initializing default_config only when the driver initialization succeeded. Reported-by: Louis Chauvet Link: https://lore.kernel.org/all/Z5uDHcCmAwiTsGte@louis-chauvet-laptop/ Fixes: 2df7af93fdad ("drm/vkms: Add vkms_config type") Signed-off-by: Jos=C3=A9 Exp=C3=B3sito Reviewed-by: Louis Chauvet Reviewed-by: Thomas Zimmermann --- drivers/gpu/drm/vkms/vkms_drv.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_dr= v.c index 7c142bfc3bd9..b6de91134a22 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.c +++ b/drivers/gpu/drm/vkms/vkms_drv.c @@ -235,17 +235,19 @@ static int __init vkms_init(void) if (!config) return -ENOMEM; =20 - default_config =3D config; - config->cursor =3D enable_cursor; config->writeback =3D enable_writeback; config->overlay =3D enable_overlay; =20 ret =3D vkms_create(config); - if (ret) + if (ret) { kfree(config); + return ret; + } =20 - return ret; + default_config =3D config; + + return 0; } =20 static void vkms_destroy(struct vkms_config *config) @@ -269,9 +271,10 @@ static void vkms_destroy(struct vkms_config *config) =20 static void __exit vkms_exit(void) { - if (default_config->dev) - vkms_destroy(default_config); + if (!default_config) + return; =20 + vkms_destroy(default_config); kfree(default_config); } =20 --=20 2.48.1