From: José Expósito Date: Wed, 12 Feb 2025 08:49:12 +0000 (+0100) Subject: drm/vkms: Fix use after free and double free on init error X-Git-Tag: block-6.15-20250403~41^2~19^2~58 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ed15511a773df86205bda66c37193569575ae828;p=linux-block.git drm/vkms: Fix use after free and double free on init error 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 Closes: 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 Link: https://patchwork.freedesktop.org/patch/msgid/20250212084912.3196-1-jose.exposito89@gmail.com Signed-off-by: Louis Chauvet --- 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); }