From: Hugo Villeneuve hvilleneuve@dimonoff.com
mainline inclusion from mainline-v6.11-rc3 commit 133f4c00b8b2bfcacead9b81e7e8edfceb4b06c4 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAOXYG CVE: CVE-2024-44951
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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serial: sc16is7xx: fix TX fifo corruption
Sometimes, when a packet is received on channel A at almost the same time as a packet is about to be transmitted on channel B, we observe with a logic analyzer that the received packet on channel A is transmitted on channel B. In other words, the Tx buffer data on channel B is corrupted with data from channel A.
The problem appeared since commit 4409df5866b7 ("serial: sc16is7xx: change EFR lock to operate on each channels"), which changed the EFR locking to operate on each channel instead of chip-wise.
This commit has introduced a regression, because the EFR lock is used not only to protect the EFR registers access, but also, in a very obscure and undocumented way, to protect access to the data buffer, which is shared by the Tx and Rx handlers, but also by each channel of the IC.
Fix this regression first by switching to kfifo_out_linear_ptr() in sc16is7xx_handle_tx() to eliminate the need for a shared Rx/Tx buffer.
Secondly, replace the chip-wise Rx buffer with a separate Rx buffer for each channel.
Fixes: 4409df5866b7 ("serial: sc16is7xx: change EFR lock to operate on each channels") Cc: stable@vger.kernel.org Signed-off-by: Hugo Villeneuve hvilleneuve@dimonoff.com Link: https://lore.kernel.org/r/20240723125302.1305372-2-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Conflicts: drivers/tty/serial/sc16is7xx.c [The cause of the conflict comes from the prefix "1788cf6a91d9fa9aa61fc2917afe192c23d67f6a tty: serial: switch from circ_buf to kfifo", which modifies a large number of files. After analysis, only the changes of sc16is7xx.c are related to the fix patch, and the modifications do not involve external interfaces. Therefore, only this part is merged to resolve the conflict.] Signed-off-by: Zhao Yipeng zhaoyipeng5@huawei.com --- drivers/tty/serial/sc16is7xx.c | 57 ++++++++++++++-------------------- 1 file changed, 24 insertions(+), 33 deletions(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 1e555421cdd2..673aeda71388 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -329,6 +329,7 @@ struct sc16is7xx_one { struct kthread_work reg_work; struct kthread_delayed_work ms_work; struct sc16is7xx_one_config config; + unsigned char buf[SC16IS7XX_FIFO_SIZE]; /* Rx buffer. */ bool irda_mode; unsigned int old_mctrl; }; @@ -341,7 +342,6 @@ struct sc16is7xx_port { unsigned long gpio_valid_mask; #endif u8 mctrl_mask; - unsigned char buf[SC16IS7XX_FIFO_SIZE]; struct kthread_worker kworker; struct task_struct *kworker_task; struct sc16is7xx_one p[]; @@ -566,18 +566,18 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud) static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen, unsigned int iir) { - struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port, port); unsigned int lsr = 0, bytes_read, i; bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false; u8 ch, flag;
- if (unlikely(rxlen >= sizeof(s->buf))) { + if (unlikely(rxlen >= sizeof(one->buf))) { dev_warn_ratelimited(port->dev, "ttySC%i: Possible RX FIFO overrun: %d\n", port->line, rxlen); port->icount.buf_overrun++; /* Ensure sanity of RX level */ - rxlen = sizeof(s->buf); + rxlen = sizeof(one->buf); }
while (rxlen) { @@ -590,10 +590,10 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen, lsr = 0;
if (read_lsr) { - s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG); + one->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG); bytes_read = 1; } else { - sc16is7xx_fifo_read(port, s->buf, rxlen); + sc16is7xx_fifo_read(port, one->buf, rxlen); bytes_read = rxlen; }
@@ -626,7 +626,7 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen, }
for (i = 0; i < bytes_read; ++i) { - ch = s->buf[i]; + ch = one->buf[i]; if (uart_handle_sysrq_char(port, ch)) continue;
@@ -644,10 +644,10 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
static void sc16is7xx_handle_tx(struct uart_port *port) { - struct sc16is7xx_port *s = dev_get_drvdata(port->dev); - struct circ_buf *xmit = &port->state->xmit; - unsigned int txlen, to_send, i; + struct tty_port *tport = &port->state->port; unsigned long flags; + unsigned int txlen; + unsigned char *tail;
if (unlikely(port->x_char)) { sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char); @@ -656,40 +656,31 @@ static void sc16is7xx_handle_tx(struct uart_port *port) return; }
- if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { + if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) { uart_port_lock_irqsave(port, &flags); sc16is7xx_stop_tx(port); uart_port_unlock_irqrestore(port, flags); return; }
- /* Get length of data pending in circular buffer */ - to_send = uart_circ_chars_pending(xmit); - if (likely(to_send)) { - /* Limit to size of TX FIFO */ - txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG); - if (txlen > SC16IS7XX_FIFO_SIZE) { - dev_err_ratelimited(port->dev, - "chip reports %d free bytes in TX fifo, but it only has %d", - txlen, SC16IS7XX_FIFO_SIZE); - txlen = 0; - } - to_send = (to_send > txlen) ? txlen : to_send; - - /* Convert to linear buffer */ - for (i = 0; i < to_send; ++i) { - s->buf[i] = xmit->buf[xmit->tail]; - uart_xmit_advance(port, 1); - } - - sc16is7xx_fifo_write(port, s->buf, to_send); + /* Limit to space available in TX FIFO */ + txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG); + if (txlen > SC16IS7XX_FIFO_SIZE) { + dev_err_ratelimited(port->dev, + "chip reports %d free bytes in TX fifo, but it only has %d", + txlen, SC16IS7XX_FIFO_SIZE); + txlen = 0; }
+ txlen = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, txlen); + sc16is7xx_fifo_write(port, tail, txlen); + uart_xmit_advance(port, txlen); + uart_port_lock_irqsave(port, &flags); - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port);
- if (uart_circ_empty(xmit)) + if (kfifo_is_empty(&tport->xmit_fifo)) sc16is7xx_stop_tx(port); else sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT);