From 38870253f1d17f872f4d2a9c6d8e2989ec3706a9 Mon Sep 17 00:00:00 2001 From: Titus Rwantare Date: Mon, 7 Mar 2022 12:05:58 -0800 Subject: hw/i2c: pmbus: fix error returns and guard against out of range accesses MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Titus Rwantare Reviewed-by: Philippe Mathieu-Daudé Acked-by: Corey Minyard Message-Id: <20220307200605.4001451-3-titusr@google.com> Signed-off-by: Philippe Mathieu-Daudé --- hw/i2c/pmbus_device.c | 47 +++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 43 insertions(+), 4 deletions(-) (limited to 'hw/i2c/pmbus_device.c') diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c index 07a45c9..c7ec8e5 100644 --- a/hw/i2c/pmbus_device.c +++ b/hw/i2c/pmbus_device.c @@ -149,7 +149,7 @@ static uint8_t pmbus_out_buf_pop(PMBusDevice *pmdev) qemu_log_mask(LOG_GUEST_ERROR, "%s: tried to read from empty buffer", __func__); - return 0xFF; + return PMBUS_ERR_BYTE; } uint8_t data = pmdev->out_buf[pmdev->out_buf_len - 1]; pmdev->out_buf_len--; @@ -243,18 +243,47 @@ void pmbus_check_limits(PMBusDevice *pmdev) } } +/* assert the status_cml error upon receipt of malformed command */ +static void pmbus_cml_error(PMBusDevice *pmdev) +{ + for (int i = 0; i < pmdev->num_pages; i++) { + pmdev->pages[i].status_word |= PMBUS_STATUS_CML; + pmdev->pages[i].status_cml |= PB_CML_FAULT_INVALID_CMD; + } +} + static uint8_t pmbus_receive_byte(SMBusDevice *smd) { PMBusDevice *pmdev = PMBUS_DEVICE(smd); PMBusDeviceClass *pmdc = PMBUS_DEVICE_GET_CLASS(pmdev); - uint8_t ret = 0xFF; - uint8_t index = pmdev->page; + uint8_t ret = PMBUS_ERR_BYTE; + uint8_t index; if (pmdev->out_buf_len != 0) { ret = pmbus_out_buf_pop(pmdev); return ret; } + /* + * Reading from all pages will return the value from page 0, + * this is unspecified behaviour in general. + */ + if (pmdev->page == PB_ALL_PAGES) { + index = 0; + qemu_log_mask(LOG_GUEST_ERROR, + "%s: tried to read from all pages\n", + __func__); + pmbus_cml_error(pmdev); + } else if (pmdev->page > pmdev->num_pages - 1) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: page %d is out of range\n", + __func__, pmdev->page); + pmbus_cml_error(pmdev); + return PMBUS_ERR_BYTE; + } else { + index = pmdev->page; + } + switch (pmdev->code) { case PMBUS_PAGE: pmbus_send8(pmdev, pmdev->page); @@ -1019,7 +1048,7 @@ static int pmbus_write_data(SMBusDevice *smd, uint8_t *buf, uint8_t len) if (len == 0) { qemu_log_mask(LOG_GUEST_ERROR, "%s: writing empty data\n", __func__); - return -1; + return PMBUS_ERR_BYTE; } if (!pmdev->pages) { /* allocate memory for pages on first use */ @@ -1038,6 +1067,7 @@ static int pmbus_write_data(SMBusDevice *smd, uint8_t *buf, uint8_t len) pmdev->page = pmbus_receive8(pmdev); return 0; } + /* loop through all the pages when 0xFF is received */ if (pmdev->page == PB_ALL_PAGES) { for (int i = 0; i < pmdev->num_pages; i++) { @@ -1048,6 +1078,15 @@ static int pmbus_write_data(SMBusDevice *smd, uint8_t *buf, uint8_t len) return 0; } + if (pmdev->page > pmdev->num_pages - 1) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: page %u is out of range\n", + __func__, pmdev->page); + pmdev->page = 0; /* undefined behaviour - reset to page 0 */ + pmbus_cml_error(pmdev); + return PMBUS_ERR_BYTE; + } + index = pmdev->page; switch (pmdev->code) { -- cgit v1.1