CVE ID:	CVE-2023-52855
Description:	In the Linux kernel, the following vulnerability has been resolved: usb: dwc2: fix possible NULL pointer dereference caused by driver concurrency In _dwc2_hcd_urb_enqueue(), "urb->hcpriv = NULL" is executed without holding the lock "hsotg->lock". In _dwc2_hcd_urb_dequeue(): spin_lock_irqsave(&hsotg->lock, flags); ... if (!urb->hcpriv) { dev_dbg(hsotg->dev, "## urb->hcpriv is NULL ##\n"); goto out; } rc = dwc2_hcd_urb_dequeue(hsotg, urb->hcpriv); // Use urb->hcpriv ... out: spin_unlock_irqrestore(&hsotg->lock, flags); When _dwc2_hcd_urb_enqueue() and _dwc2_hcd_urb_dequeue() are concurrently executed, the NULL check of "urb->hcpriv" can be executed before "urb->hcpriv = NULL". After urb->hcpriv is NULL, it can be used in the function call to dwc2_hcd_urb_dequeue(), which can cause a NULL pointer dereference. This possible bug is found by an experimental static analysis tool developed by myself. This tool analyzes the locking APIs to extract function pairs that can be concurrently executed, and then analyzes the instructions in the paired functions to identify possible concurrency bugs including data races and atomicity violations. The above possible bug is reported, when my tool analyzes the source code of Linux 6.5. To fix this possible bug, "urb->hcpriv = NULL" should be executed with holding the lock "hsotg->lock". After using this patch, my tool never reports the possible bug, with the kernelconfiguration allyesconfig for x86_64. Because I have no associated hardware, I cannot test the patch in runtime testing, and just verify it according to the code logic.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2023-52855 https://git.kernel.org/stable/c/14c9ec34e8118fbffd7f5431814d767726323e72 https://git.kernel.org/stable/c/14c9ec34e8118fbffd7f5431814d767726323e72 https://git.kernel.org/stable/c/3e851a77a13ce944d703721793f49ee82622986d https://git.kernel.org/stable/c/3e851a77a13ce944d703721793f49ee82622986d https://git.kernel.org/stable/c/64c47749fc7507ed732e155c958253968c1d275e https://git.kernel.org/stable/c/64c47749fc7507ed732e155c958253968c1d275e https://git.kernel.org/stable/c/6b21a22728852d020a6658d39cd7bb7e14b07790 https://git.kernel.org/stable/c/6b21a22728852d020a6658d39cd7bb7e14b07790 https://git.kernel.org/stable/c/a7bee9598afb38004841a41dd8fe68c1faff4e90 https://git.kernel.org/stable/c/a7bee9598afb38004841a41dd8fe68c1faff4e90 https://git.kernel.org/stable/c/bdb3dd4096302d6b87441fdc528439f171b04be6 https://git.kernel.org/stable/c/bdb3dd4096302d6b87441fdc528439f171b04be6 https://git.kernel.org/stable/c/ef307bc6ef04e8c1ea843231db58e3afaafa9fa6 https://git.kernel.org/stable/c/ef307bc6ef04e8c1ea843231db58e3afaafa9fa6 https://git.kernel.org/stable/c/fcaafb574fc88a52dce817f039f7ff2f9da38001 https://git.kernel.org/stable/c/fcaafb574fc88a52dce817f039f7ff2f9da38001 https://git.kernel.org/stable/c/fed492aa6493a91a77ebd51da6fb939c98d94a0d https://git.kernel.org/stable/c/fed492aa6493a91a77ebd51da6fb939c98d94a0d