Date: Fri, 8 Dec 2017 05:32:18 +0000 (UTC) From: Alan Somers <asomers@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r326680 - stable/11/sys/cam/scsi Message-ID: <201712080532.vB85WIa1034905@repo.freebsd.org>
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Author: asomers Date: Fri Dec 8 05:32:17 2017 New Revision: 326680 URL: https://svnweb.freebsd.org/changeset/base/326680 Log: MFC r325947: Fix potential NULL pointer dereference of device physical path In scsi_dev_advinfo(), if the physical path is being stored and there is a malloc failure (malloc(9) is called with M_NOWAIT), we could wind up in a situation where the device's physpath_len is set to the length the user provided, but the physpath itself is NULL. If another context then comes in to fetch the physical path value, we would wind up trying to memcpy a NULL pointer into the caller's buffer. So, set the physpath_len to 0 when we free the physpath on entry into the store case for the physical path. Reset the length to a non-zero value only after we've successfully malloced a buffer to hold it. Submitted by: ken Reviewed by: asomers Sponsored by: Spectra Logic Corp Modified: stable/11/sys/cam/scsi/scsi_xpt.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/cam/scsi/scsi_xpt.c ============================================================================== --- stable/11/sys/cam/scsi/scsi_xpt.c Fri Dec 8 05:26:10 2017 (r326679) +++ stable/11/sys/cam/scsi/scsi_xpt.c Fri Dec 8 05:32:17 2017 (r326680) @@ -2506,8 +2506,8 @@ scsi_dev_advinfo(union ccb *start_ccb) if (device->physpath != NULL) { free(device->physpath, M_CAMXPT); device->physpath = NULL; + device->physpath_len = 0; } - device->physpath_len = cdai->bufsiz; /* Clear existing buffer if zero length */ if (cdai->bufsiz == 0) break; @@ -2516,6 +2516,7 @@ scsi_dev_advinfo(union ccb *start_ccb) start_ccb->ccb_h.status = CAM_REQ_ABORTED; return; } + device->physpath_len = cdai->bufsiz; memcpy(device->physpath, cdai->buf, cdai->bufsiz); } else { cdai->provsiz = device->physpath_len;
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