[PATCH openEuler-1.0-LTS 1/2] xhci: Fix command ring pointer corruption while aborting a command
From: Pavankumar Kondeti <pkondeti@codeaurora.org> stable inclusion from stable-v4.19.213 commit dec944bb7079b37968cf69c8a438f91f15c4cc61 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RB55 CVE: CVE-2021-47434 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit ff0e50d3564f33b7f4b35cadeabd951d66cfc570 upstream. The command ring pointer is located at [6:63] bits of the command ring control register (CRCR). All the control bits like command stop, abort are located at [0:3] bits. While aborting a command, we read the CRCR and set the abort bit and write to the CRCR. The read will always give command ring pointer as all zeros. So we essentially write only the control bits. Since we split the 64 bit write into two 32 bit writes, there is a possibility of xHC command ring stopped before the upper dword (all zeros) is written. If that happens, xHC updates the upper dword of its internal command ring pointer with all zeros. Next time, when the command ring is restarted, we see xHC memory access failures. Fix this issue by only writing to the lower dword of CRCR where all control bits are located. Cc: stable@vger.kernel.org Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20211008092547.3996295-5-mathias.nyman@linux.intel... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yuan Can <yuancan@huawei.com> --- drivers/usb/host/xhci-ring.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 98b67605d3cf..22655e0d257a 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -339,16 +339,22 @@ static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci, /* Must be called with xhci->lock held, releases and aquires lock back */ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags) { - u64 temp_64; + u32 temp_32; int ret; xhci_dbg(xhci, "Abort command ring\n"); reinit_completion(&xhci->cmd_ring_stop_completion); - temp_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring); - xhci_write_64(xhci, temp_64 | CMD_RING_ABORT, - &xhci->op_regs->cmd_ring); + /* + * The control bits like command stop, abort are located in lower + * dword of the command ring control register. Limit the write + * to the lower dword to avoid corrupting the command ring pointer + * in case if the command ring is stopped by the time upper dword + * is written. + */ + temp_32 = readl(&xhci->op_regs->cmd_ring); + writel(temp_32 | CMD_RING_ABORT, &xhci->op_regs->cmd_ring); /* Section 4.6.1.2 of xHCI 1.0 spec says software should also time the * completion of the Command Abort operation. If CRR is not negated in 5 -- 2.17.1
From: Mathias Nyman <mathias.nyman@linux.intel.com> stable inclusion from stable-v4.19.220 commit abba418a9c73dcffecbe19ef93c7ae5d2e8e38d3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RB55 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- Turns out some xHC controllers require all 64 bits in the CRCR register to be written to execute a command abort. The lower 32 bits containing the command abort bit is written first. In case the command ring stops before we write the upper 32 bits then hardware may use these upper bits to set the commnd ring dequeue pointer. Solve this by making sure the upper 32 bits contain a valid command ring dequeue pointer. The original patch that only wrote the first 32 to stop the ring went to stable, so this fix should go there as well. Fixes: ff0e50d3564f ("xhci: Fix command ring pointer corruption while aborting a command") Cc: stable@vger.kernel.org Tested-by: Pavankumar Kondeti <quic_pkondeti@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20211126122340.1193239-2-mathias.nyman@linux.intel... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yuan Can <yuancan@huawei.com> --- drivers/usb/host/xhci-ring.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 22655e0d257a..dadc6f43ad69 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -339,7 +339,9 @@ static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci, /* Must be called with xhci->lock held, releases and aquires lock back */ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags) { - u32 temp_32; + struct xhci_segment *new_seg = xhci->cmd_ring->deq_seg; + union xhci_trb *new_deq = xhci->cmd_ring->dequeue; + u64 crcr; int ret; xhci_dbg(xhci, "Abort command ring\n"); @@ -348,13 +350,18 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags) /* * The control bits like command stop, abort are located in lower - * dword of the command ring control register. Limit the write - * to the lower dword to avoid corrupting the command ring pointer - * in case if the command ring is stopped by the time upper dword - * is written. + * dword of the command ring control register. + * Some controllers require all 64 bits to be written to abort the ring. + * Make sure the upper dword is valid, pointing to the next command, + * avoiding corrupting the command ring pointer in case the command ring + * is stopped by the time the upper dword is written. */ - temp_32 = readl(&xhci->op_regs->cmd_ring); - writel(temp_32 | CMD_RING_ABORT, &xhci->op_regs->cmd_ring); + next_trb(xhci, NULL, &new_seg, &new_deq); + if (trb_is_link(new_deq)) + next_trb(xhci, NULL, &new_seg, &new_deq); + + crcr = xhci_trb_virt_to_dma(new_seg, new_deq); + xhci_write_64(xhci, crcr | CMD_RING_ABORT, &xhci->op_regs->cmd_ring); /* Section 4.6.1.2 of xHCI 1.0 spec says software should also time the * completion of the Command Abort operation. If CRR is not negated in 5 -- 2.17.1
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