From: Qinglang Miao <miaoqinglang@huawei.com> To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch> Cc: <dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>, Qinglang Miao <miaoqinglang@huawei.com> Subject: [PATCH] drm/dev: Fix NULL pointer dereference in drm_minor_alloc Date: Fri, 27 Nov 2020 17:43:55 +0800 [thread overview] Message-ID: <20201127094355.120520-1-miaoqinglang@huawei.com> (raw) KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 0 PID: 18491 Comm: syz-executor.0 Tainted: G C 5.10.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:kobject_put+0x2f/0x140 Call Trace: put_device+0x20/0x40 drm_minor_alloc_release+0x60/0xe0 [drm] drm_managed_release+0x1b6/0x440 [drm] drm_dev_init+0x50b/0x8e0 [drm] __devm_drm_dev_alloc+0x50/0x160 [drm] vgem_init+0x15c/0x1000 [vgem] do_one_initcall+0x149/0x7e0 do_init_module+0x1ef/0x700 load_module+0x3467/0x4140 __do_sys_finit_module+0x10d/0x1a0 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kfree(minor->kdev) in put_device would raise a null-ptr-deref bug when minor->kdev is null or error pointer. So do check before put_device in drm_minor_alloc_release and prohibit minor->kdev becoming an error pointer. Fixes: f96306f9892b ("drm: manage drm_minor cleanup with drmm_") Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> --- drivers/gpu/drm/drm_drv.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index cd162d406..c253d3cd4 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -100,7 +100,8 @@ static void drm_minor_alloc_release(struct drm_device *dev, void *data) WARN_ON(dev != minor->dev); - put_device(minor->kdev); + if (minor->kdev) + put_device(minor->kdev); spin_lock_irqsave(&drm_minor_lock, flags); idr_remove(&drm_minors_idr, minor->index); @@ -140,8 +141,11 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) return r; minor->kdev = drm_sysfs_minor_alloc(minor); - if (IS_ERR(minor->kdev)) - return PTR_ERR(minor->kdev); + if (IS_ERR(minor->kdev)) { + r = PTR_ERR(minor->kdev); + minor->kdev = NULL; + return r; + } *drm_minor_get_slot(dev, type) = minor; return 0; -- 2.23.0
WARNING: multiple messages have this Message-ID (diff)
From: Qinglang Miao <miaoqinglang@huawei.com> To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch> Cc: Qinglang Miao <miaoqinglang@huawei.com>, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH] drm/dev: Fix NULL pointer dereference in drm_minor_alloc Date: Fri, 27 Nov 2020 17:43:55 +0800 [thread overview] Message-ID: <20201127094355.120520-1-miaoqinglang@huawei.com> (raw) KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 0 PID: 18491 Comm: syz-executor.0 Tainted: G C 5.10.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:kobject_put+0x2f/0x140 Call Trace: put_device+0x20/0x40 drm_minor_alloc_release+0x60/0xe0 [drm] drm_managed_release+0x1b6/0x440 [drm] drm_dev_init+0x50b/0x8e0 [drm] __devm_drm_dev_alloc+0x50/0x160 [drm] vgem_init+0x15c/0x1000 [vgem] do_one_initcall+0x149/0x7e0 do_init_module+0x1ef/0x700 load_module+0x3467/0x4140 __do_sys_finit_module+0x10d/0x1a0 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kfree(minor->kdev) in put_device would raise a null-ptr-deref bug when minor->kdev is null or error pointer. So do check before put_device in drm_minor_alloc_release and prohibit minor->kdev becoming an error pointer. Fixes: f96306f9892b ("drm: manage drm_minor cleanup with drmm_") Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> --- drivers/gpu/drm/drm_drv.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index cd162d406..c253d3cd4 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -100,7 +100,8 @@ static void drm_minor_alloc_release(struct drm_device *dev, void *data) WARN_ON(dev != minor->dev); - put_device(minor->kdev); + if (minor->kdev) + put_device(minor->kdev); spin_lock_irqsave(&drm_minor_lock, flags); idr_remove(&drm_minors_idr, minor->index); @@ -140,8 +141,11 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) return r; minor->kdev = drm_sysfs_minor_alloc(minor); - if (IS_ERR(minor->kdev)) - return PTR_ERR(minor->kdev); + if (IS_ERR(minor->kdev)) { + r = PTR_ERR(minor->kdev); + minor->kdev = NULL; + return r; + } *drm_minor_get_slot(dev, type) = minor; return 0; -- 2.23.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next reply other threads:[~2020-11-27 9:39 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-27 9:43 Qinglang Miao [this message] 2020-11-27 9:43 ` [PATCH] drm/dev: Fix NULL pointer dereference in drm_minor_alloc Qinglang Miao
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