6.18-stable review patch. If anyone has any objections, please let me know.
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From: Tianchu Chen flynnnchen@tencent.com
[ Upstream commit 545d1287e40a55242f6ab68bcc1ba3b74088b1bc ]
Discovered by Atuin - Automated Vulnerability Discovery Engine.
The 'len' variable is calculated as 'min(32, trans->len + 1)', which includes the 1-byte command header.
When copying data from 'trans->tx_buf' to 'ch341->tx_buf + 1', using 'len' as the length is incorrect because:
1. It causes an out-of-bounds read from 'trans->tx_buf' (which has size 'trans->len', i.e., 'len - 1' in this context). 2. It can cause an out-of-bounds write to 'ch341->tx_buf' if 'len' is CH341_PACKET_LENGTH (32). Writing 32 bytes to ch341->tx_buf + 1 overflows the buffer.
Fix this by copying 'len - 1' bytes.
Fixes: 8846739f52af ("spi: add ch341a usb2spi driver") Signed-off-by: Tianchu Chen flynnnchen@tencent.com Link: https://patch.msgid.link/20251128160630.0f922c45ec6084a46fb57099@linux.dev Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-ch341.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-ch341.c b/drivers/spi/spi-ch341.c index 46bc208f2d050..79d2f9ab4ef03 100644 --- a/drivers/spi/spi-ch341.c +++ b/drivers/spi/spi-ch341.c @@ -78,7 +78,7 @@ static int ch341_transfer_one(struct spi_controller *host,
ch341->tx_buf[0] = CH341A_CMD_SPI_STREAM;
- memcpy(ch341->tx_buf + 1, trans->tx_buf, len); + memcpy(ch341->tx_buf + 1, trans->tx_buf, len - 1);
ret = usb_bulk_msg(ch341->udev, ch341->write_pipe, ch341->tx_buf, len, NULL, CH341_DEFAULT_TIMEOUT);