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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?b?Sm9zw6kgRXhww7NzaXRv?= 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?b?Sm9zw6kgRXhww7NzaXRv?= 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 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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: José Expósito Reviewed-by: Thomas Zimmermann Reviewed-by: Louis Chauvet --- 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_drv.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; - default_config = config; - config->cursor = enable_cursor; config->writeback = enable_writeback; config->overlay = enable_overlay; ret = vkms_create(config); - if (ret) + if (ret) { kfree(config); + return ret; + } - return ret; + default_config = config; + + return 0; } static void vkms_destroy(struct vkms_config *config) @@ -269,9 +271,10 @@ static void vkms_destroy(struct vkms_config *config) static void __exit vkms_exit(void) { - if (default_config->dev) - vkms_destroy(default_config); + if (!default_config) + return; + vkms_destroy(default_config); kfree(default_config); }