git: 763179042246 - main - Fix NULL deref segfault in bhyve's usb_mouse.c

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=7631790422464de1aec309018e2c444defe5f629

commit 7631790422464de1aec309018e2c444defe5f629
Author:     Jack Bendtsen <jackdbendtsen@gmail.com>
AuthorDate: 2025-06-19 07:40:31 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2026-01-09 20:17:13 +0000

    Fix NULL deref segfault in bhyve's usb_mouse.c
    
    Some of the cases inside umouse_request() (usr.sbin/bhyve/usb_mouse.c)
    use the data component of an event, while only partially checking if
    it's NULL. 'data' has a NULL check, but then 'data' is immediately
    deferenced anyway after the check regardless of if it's NULL or not.
    
    For example:
            case UREQ(UR_GET_STATUS, UT_READ_INTERFACE):
            case UREQ(UR_GET_STATUS, UT_READ_ENDPOINT):
                    DPRINTF(("umouse: (UR_GET_STATUS, UT_READ_INTERFACE)"));
                    if (data != NULL && len > 1) {
                            USETW(udata, 0);
                            data->blen = len - 2;
                            data->bdone += 2;
                    }
                    eshort = data->blen > 0;
                    break;
    
    There are actually four occurrences of this same bug, each in a
    different case in this switch block.
    
    Signed-off-by: Jack Bendtsen <jackdbendtsen@gmail.com>
    PR: 282237
    Reviewed by: imp, jhb, vexeduxr
    MFC After: 1 week
    Pull Request: https://github.com/freebsd/freebsd-src/pull/1728
---
 usr.sbin/bhyve/usb_mouse.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/usr.sbin/bhyve/usb_mouse.c b/usr.sbin/bhyve/usb_mouse.c
index 82b1159d5f61..5caad886e082 100644
--- a/usr.sbin/bhyve/usb_mouse.c
+++ b/usr.sbin/bhyve/usb_mouse.c
@@ -538,7 +538,7 @@ umouse_request(void *scarg, struct usb_data_xfer *xfer)
 			data->bdone += 2;
 		}
 
-		eshort = data->blen > 0;
+		eshort = data != NULL && data->blen > 0;
 		break;
 
 	case UREQ(UR_GET_STATUS, UT_READ_INTERFACE):
@@ -549,7 +549,7 @@ umouse_request(void *scarg, struct usb_data_xfer *xfer)
 			data->blen = len - 2;
 			data->bdone += 2;
 		}
-		eshort = data->blen > 0;
+		eshort = data != NULL && data->blen > 0;
 		break;
 
 	case UREQ(UR_SET_ADDRESS, UT_WRITE_DEVICE):
@@ -634,7 +634,7 @@ umouse_request(void *scarg, struct usb_data_xfer *xfer)
 			data->blen = len - 1;
 			data->bdone += 1;
 		}
-		eshort = data->blen > 0;
+		eshort = data != NULL && data->blen > 0;
 		break;
 
 	case UREQ(UMOUSE_GET_PROTOCOL, UT_READ_CLASS_INTERFACE):
@@ -643,7 +643,7 @@ umouse_request(void *scarg, struct usb_data_xfer *xfer)
 			data->blen = len - 1;
 			data->bdone += 1;
 		}
-		eshort = data->blen > 0;
+		eshort = data != NULL && data->blen > 0;
 		break;
 
 	case UREQ(UMOUSE_SET_REPORT, UT_WRITE_CLASS_INTERFACE):