| Message ID | 20210507183757.68810-1-trix@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Jiri Kosina |
| Headers | show |
| Series | HID: ft260: improve error handling of ft260_hid_feature_report_get() | expand |
On Fri, May 07, 2021 at 11:37:57AM -0700, trix@redhat.com wrote: > From: Tom Rix <trix@redhat.com> > > Static analysis reports this representative problem > > hid-ft260.c:787:9: warning: 4th function call argument is an > uninitialized value > return scnprintf(buf, PAGE_SIZE, "%hi\n", *field); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Uses of ft260_hid_feature_report_get() check if the return size matches > the requested size. But the function can also fail with at least -ENOMEM. > Add the < 0 checks. Hi Tom, thanks for catching and fixing it! I applied the patch, built the driver, and run some tests on my HW setup - no regression so far. But I think the fix can be improved even more, by reducing the number of questions to one in the successful case where the performance matters. Please see the proposal below inline. > > In ft260_hid_feature_report_get(), do not do the memcpy to the caller's > buffer if there is an error. > > Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver") > Signed-off-by: Tom Rix <trix@redhat.com> > --- > drivers/hid/hid-ft260.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c > index 7a9ba984a75a..628fa664a10b 100644 > --- a/drivers/hid/hid-ft260.c > +++ b/drivers/hid/hid-ft260.c > @@ -249,7 +249,8 @@ static int ft260_hid_feature_report_get(struct hid_device *hdev, > > ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT, > HID_REQ_GET_REPORT); > - memcpy(data, buf, len); > + if (ret == len) > + memcpy(data, buf, len); > kfree(buf); > return ret; > } > @@ -295,12 +296,16 @@ static int ft260_xfer_status(struct ft260_device *dev) > struct hid_device *hdev = dev->hdev; > struct ft260_get_i2c_status_report report; > int ret; > + int len = sizeof(report); > > ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS, > - (u8 *)&report, sizeof(report)); > - if (ret < 0) { > + (u8 *)&report, len); > + if (ret != len) { > hid_err(hdev, "failed to retrieve status: %d\n", ret); > - return ret; > + if (ret >= 0) > + return -EIO; > + else > + return ret; > } > > dev->clock = le16_to_cpu(report.clock); > @@ -728,6 +733,8 @@ static int ft260_get_system_config(struct hid_device *hdev, > hid_err(hdev, "failed to retrieve system status\n"); > if (ret >= 0) > return -EIO; > + else > + return ret; > } > return 0; > } > @@ -782,6 +789,8 @@ static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len, > ret = ft260_hid_feature_report_get(hdev, id, cfg, len); > if (ret != len && ret >= 0) > return -EIO; > + else if (ret < 0) > + return ret; Please consider the below code to reduce the number of questions to one in the "likely" case and two in the worst-case scenario. if (ret != len) { if (ret >= 0) return -EIO; else return ret; } > > return scnprintf(buf, PAGE_SIZE, "%hi\n", *field); > } > @@ -794,6 +803,8 @@ static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len, > ret = ft260_hid_feature_report_get(hdev, id, cfg, len); > if (ret != len && ret >= 0) > return -EIO; > + else if (ret < 0) > + return ret; The same. > > return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field)); > } > -- > 2.26.3 >
diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c index 7a9ba984a75a..628fa664a10b 100644 --- a/drivers/hid/hid-ft260.c +++ b/drivers/hid/hid-ft260.c @@ -249,7 +249,8 @@ static int ft260_hid_feature_report_get(struct hid_device *hdev, ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT, HID_REQ_GET_REPORT); - memcpy(data, buf, len); + if (ret == len) + memcpy(data, buf, len); kfree(buf); return ret; } @@ -295,12 +296,16 @@ static int ft260_xfer_status(struct ft260_device *dev) struct hid_device *hdev = dev->hdev; struct ft260_get_i2c_status_report report; int ret; + int len = sizeof(report); ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS, - (u8 *)&report, sizeof(report)); - if (ret < 0) { + (u8 *)&report, len); + if (ret != len) { hid_err(hdev, "failed to retrieve status: %d\n", ret); - return ret; + if (ret >= 0) + return -EIO; + else + return ret; } dev->clock = le16_to_cpu(report.clock); @@ -728,6 +733,8 @@ static int ft260_get_system_config(struct hid_device *hdev, hid_err(hdev, "failed to retrieve system status\n"); if (ret >= 0) return -EIO; + else + return ret; } return 0; } @@ -782,6 +789,8 @@ static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len, ret = ft260_hid_feature_report_get(hdev, id, cfg, len); if (ret != len && ret >= 0) return -EIO; + else if (ret < 0) + return ret; return scnprintf(buf, PAGE_SIZE, "%hi\n", *field); } @@ -794,6 +803,8 @@ static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len, ret = ft260_hid_feature_report_get(hdev, id, cfg, len); if (ret != len && ret >= 0) return -EIO; + else if (ret < 0) + return ret; return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field)); }