+1 for M_ZERO. -- Shawn Webb Cofounder / Security Engineer HardenedBSD
Tor-ified Signal: +1 443-546-8752 Tor+XMPP+OTR: latt...@is.a.hacker.sx GPG Key ID: 0xFF2E67A277F8E1FA GPG Key Fingerprint: D206 BB45 15E0 9C49 0CF9 3633 C85B 0AF8 AB23 0FB2 On Thu, Jun 20, 2019 at 04:59:48PM -0600, Scott Long wrote: > Hi Alexander, > > I???m not a fan of removing the M_ZERO. I understand your argument that > lengths are provided elsewhere, but having the buffer be zero???d is defensive > against future bugs that might leak buffer contents. GETATTR isn???t > typically > in a performance path, is there any measurable benefit to this? > > Thanks, > Scott > > > > On Jun 20, 2019, at 2:29 PM, Alexander Motin <m...@freebsd.org> wrote: > > > > Author: mav > > Date: Thu Jun 20 20:29:42 2019 > > New Revision: 349243 > > URL: https://svnweb.freebsd.org/changeset/base/349243 > > > > Log: > > Optimize xpt_getattr(). > > > > Do not allocate temporary buffer for attributes we are going to return > > as-is, just make sure to NUL-terminate them. Do not zero temporary 64KB > > buffer for CDAI_TYPE_SCSI_DEVID, XPT tells us how much data it filled > > and there are also length fields inside the returned data also. > > > > MFC after: 2 weeks > > Sponsored by: iXsystems, Inc. > > > > Modified: > > head/sys/cam/cam_xpt.c > > > > Modified: head/sys/cam/cam_xpt.c > > ============================================================================== > > --- head/sys/cam/cam_xpt.c Thu Jun 20 20:06:19 2019 (r349242) > > +++ head/sys/cam/cam_xpt.c Thu Jun 20 20:29:42 2019 (r349243) > > @@ -1253,6 +1253,7 @@ xpt_getattr(char *buf, size_t len, const char *attr, s > > cdai.ccb_h.func_code = XPT_DEV_ADVINFO; > > cdai.flags = CDAI_FLAG_NONE; > > cdai.bufsiz = len; > > + cdai.buf = buf; > > > > if (!strcmp(attr, "GEOM::ident")) > > cdai.buftype = CDAI_TYPE_SERIAL_NUM; > > @@ -1262,14 +1263,14 @@ xpt_getattr(char *buf, size_t len, const char > > *attr, s > > strcmp(attr, "GEOM::lunname") == 0) { > > cdai.buftype = CDAI_TYPE_SCSI_DEVID; > > cdai.bufsiz = CAM_SCSI_DEVID_MAXLEN; > > + cdai.buf = malloc(cdai.bufsiz, M_CAMXPT, M_NOWAIT); > > + if (cdai.buf == NULL) { > > + ret = ENOMEM; > > + goto out; > > + } > > } else > > goto out; > > > > - cdai.buf = malloc(cdai.bufsiz, M_CAMXPT, M_NOWAIT|M_ZERO); > > - if (cdai.buf == NULL) { > > - ret = ENOMEM; > > - goto out; > > - } > > xpt_action((union ccb *)&cdai); /* can only be synchronous */ > > if ((cdai.ccb_h.status & CAM_DEV_QFRZN) != 0) > > cam_release_devq(cdai.ccb_h.path, 0, 0, 0, FALSE); > > @@ -1334,13 +1335,15 @@ xpt_getattr(char *buf, size_t len, const char > > *attr, s > > ret = EFAULT; > > } > > } else { > > - ret = 0; > > - if (strlcpy(buf, cdai.buf, len) >= len) > > + if (cdai.provsiz < len) { > > + cdai.buf[cdai.provsiz] = 0; > > + ret = 0; > > + } else > > ret = EFAULT; > > } > > > > out: > > - if (cdai.buf != NULL) > > + if ((char *)cdai.buf != buf) > > free(cdai.buf, M_CAMXPT); > > return ret; > > } > > > > _______________________________________________ > svn-src-all@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/svn-src-all > To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
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