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drm/vkms: Fix use after free and double free on init error

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[ Upstream commit ed15511a773df86205bda66c37193569575ae828 ]

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 <louis.chauvet@bootlin.com>
Closes: https://lore.kernel.org/all/Z5uDHcCmAwiTsGte@louis-chauvet-laptop/
Fixes: 2df7af93fd ("drm/vkms: Add vkms_config type")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmremann@suse.de>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250212084912.3196-1-jose.exposito89@gmail.com
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
José Expósito 2025-02-12 09:49:12 +01:00 committed by Greg Kroah-Hartman
parent f3ce74cdee
commit 79d138d137
1 changed files with 9 additions and 6 deletions
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15
drivers/gpu/drm/vkms/vkms_drv.c
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@ -226,17 +226,19 @@ static int __init vkms_init(void)
if (!config) if (!config)
return -ENOMEM; return -ENOMEM;
default_config = config;
config->cursor = enable_cursor; config->cursor = enable_cursor;
config->writeback = enable_writeback; config->writeback = enable_writeback;
config->overlay = enable_overlay; config->overlay = enable_overlay;
ret = vkms_create(config); ret = vkms_create(config);
if (ret) if (ret) {
kfree(config); kfree(config);
return ret;
}
return ret; default_config = config;
return 0;
} }
static void vkms_destroy(struct vkms_config *config) static void vkms_destroy(struct vkms_config *config)
@ -260,9 +262,10 @@ static void vkms_destroy(struct vkms_config *config)
static void __exit vkms_exit(void) static void __exit vkms_exit(void)
{ {
if (default_config->dev) if (!default_config)
vkms_destroy(default_config); return;
vkms_destroy(default_config);
kfree(default_config); kfree(default_config);
} }