CVE-2021-47269

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> usb: dwc3: ep0: fix NULL pointer exception<br /> <br /> There is no validation of the index from dwc3_wIndex_to_dep() and we might<br /> be referring a non-existing ep and trigger a NULL pointer exception. In<br /> certain configurations we might use fewer eps and the index might wrongly<br /> indicate a larger ep index than existing.<br /> <br /> By adding this validation from the patch we can actually report a wrong<br /> index back to the caller.<br /> <br /> In our usecase we are using a composite device on an older kernel, but<br /> upstream might use this fix also. Unfortunately, I cannot describe the<br /> hardware for others to reproduce the issue as it is a proprietary<br /> implementation.<br /> <br /> [ 82.958261] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a4<br /> [ 82.966891] Mem abort info:<br /> [ 82.969663] ESR = 0x96000006<br /> [ 82.972703] Exception class = DABT (current EL), IL = 32 bits<br /> [ 82.978603] SET = 0, FnV = 0<br /> [ 82.981642] EA = 0, S1PTW = 0<br /> [ 82.984765] Data abort info:<br /> [ 82.987631] ISV = 0, ISS = 0x00000006<br /> [ 82.991449] CM = 0, WnR = 0<br /> [ 82.994409] user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c6210ccc<br /> [ 83.000999] [00000000000000a4] pgd=0000000053aa5003, pud=0000000053aa5003, pmd=0000000000000000<br /> [ 83.009685] Internal error: Oops: 96000006 [#1] PREEMPT SMP<br /> [ 83.026433] Process irq/62-dwc3 (pid: 303, stack limit = 0x000000003985154c)<br /> [ 83.033470] CPU: 0 PID: 303 Comm: irq/62-dwc3 Not tainted 4.19.124 #1<br /> [ 83.044836] pstate: 60000085 (nZCv daIf -PAN -UAO)<br /> [ 83.049628] pc : dwc3_ep0_handle_feature+0x414/0x43c<br /> [ 83.054558] lr : dwc3_ep0_interrupt+0x3b4/0xc94<br /> <br /> ...<br /> <br /> [ 83.141788] Call trace:<br /> [ 83.144227] dwc3_ep0_handle_feature+0x414/0x43c<br /> [ 83.148823] dwc3_ep0_interrupt+0x3b4/0xc94<br /> [ 83.181546] ---[ end trace aac6b5267d84c32f ]---