The branch main has been updated by markj:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=d068ea16e3264c2d62472a8acf794262cfe703dd

commit d068ea16e3264c2d62472a8acf794262cfe703dd
Author:     Mark Johnston <ma...@freebsd.org>
AuthorDate: 2023-12-28 17:08:04 +0000
Commit:     Mark Johnston <ma...@freebsd.org>
CommitDate: 2023-12-28 17:36:15 +0000

    cam: Let cam_periph_unmapmem() return an error
    
    As of commit b059686a71c8, cam_periph_unmapmem() can legitimately fail
    if the copyout() operation fails.  However, this failure was never
    signaled to upper layers.  In practice it is unlikely to occur
    since cap_periph_mapmem() would most likely fail in such
    circumstances anyway, but an error is nonetheless possible.
    
    However, some code reading revealed a few paths where the return value
    of cam_periph_mapmem() is not checked, and this is definitely a bug.
    Add error checking there and let cam_periph_unmapmem() return errors
    from copyout().
    
    Reviewed by:    dab, mav
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D43201
---
 sys/cam/cam_compat.c       | 21 +++++++++++++--------
 sys/cam/cam_periph.c       | 21 +++++++++++++--------
 sys/cam/cam_periph.h       |  2 +-
 sys/cam/cam_xpt.c          |  4 +---
 sys/cam/nvme/nvme_da.c     |  5 +++--
 sys/cam/scsi/scsi_pass.c   |  4 ++--
 sys/cam/scsi/scsi_sg.c     |  6 ++++--
 sys/cam/scsi/scsi_target.c | 29 ++++++++++++++++++++---------
 8 files changed, 57 insertions(+), 35 deletions(-)

diff --git a/sys/cam/cam_compat.c b/sys/cam/cam_compat.c
index 1b53eaa4a2c8..fdb4ee8717ec 100644
--- a/sys/cam/cam_compat.c
+++ b/sys/cam/cam_compat.c
@@ -377,11 +377,13 @@ cam_compat_translate_dev_match_0x18(union ccb *ccb)
        struct dev_match_result         *dm;
        struct dev_match_result_0x18    *dm18;
        struct cam_periph_map_info      mapinfo;
-       int i;
+       int error, i;
 
        /* Remap the CCB into kernel address space */
        bzero(&mapinfo, sizeof(mapinfo));
-       cam_periph_mapmem(ccb, &mapinfo, maxphys);
+       error = cam_periph_mapmem(ccb, &mapinfo, maxphys);
+       if (error != 0)
+               return (error);
 
        dm = ccb->cdm.matches;
        /* Translate in-place: old fields are smaller */
@@ -429,21 +431,22 @@ cam_compat_translate_dev_match_0x18(union ccb *ccb)
                }
        }
 
-       cam_periph_unmapmem(ccb, &mapinfo);
-
-       return (0);
+       return (cam_periph_unmapmem(ccb, &mapinfo));
 }
 
 static int
 cam_compat_handle_0x19(struct cdev *dev, u_long cmd, caddr_t addr, int flag,
     struct thread *td, d_ioctl_t *cbfnp)
 {
+       struct cam_periph_map_info mapinfo;
        union ccb *ccb = (union ccb *)addr;
-       struct cam_periph_map_info      mapinfo;
+       int error;
 
        if (cmd == CAMIOCOMMAND && ccb->ccb_h.func_code == XPT_DEV_MATCH) {
                bzero(&mapinfo, sizeof(mapinfo));
-               cam_periph_mapmem(ccb, &mapinfo, maxphys);
+               error = cam_periph_mapmem(ccb, &mapinfo, maxphys);
+               if (error != 0)
+                       return (error);
                for (int i = 0; i < ccb->cdm.num_patterns; i++) {
                        struct dev_match_pattern *p = &ccb->cdm.patterns[i];
 
@@ -457,7 +460,9 @@ cam_compat_handle_0x19(struct cdev *dev, u_long cmd, 
caddr_t addr, int flag,
                            p->pattern.periph_pattern.flags == 0x01f)
                                p->pattern.periph_pattern.flags = 
PERIPH_MATCH_ANY;
                }
-               cam_periph_unmapmem(ccb, &mapinfo);
+               error = cam_periph_unmapmem(ccb, &mapinfo);
+               if (error != 0)
+                       return (error);
        }
        return ((cbfnp)(dev, cmd, addr, flag, td));
 }
diff --git a/sys/cam/cam_periph.c b/sys/cam/cam_periph.c
index 920e5f0471c7..e957edee67f1 100644
--- a/sys/cam/cam_periph.c
+++ b/sys/cam/cam_periph.c
@@ -1013,17 +1013,17 @@ fail:
  * Unmap memory segments mapped into kernel virtual address space by
  * cam_periph_mapmem().
  */
-void
+int
 cam_periph_unmapmem(union ccb *ccb, struct cam_periph_map_info *mapinfo)
 {
-       int numbufs, i;
+       int error, numbufs, i;
        uint8_t **data_ptrs[CAM_PERIPH_MAXMAPS];
        uint32_t lengths[CAM_PERIPH_MAXMAPS];
        uint32_t dirs[CAM_PERIPH_MAXMAPS];
 
        if (mapinfo->num_bufs_used <= 0) {
                /* nothing to free and the process wasn't held. */
-               return;
+               return (0);
        }
 
        switch (ccb->ccb_h.func_code) {
@@ -1088,12 +1088,11 @@ cam_periph_unmapmem(union ccb *ccb, struct 
cam_periph_map_info *mapinfo)
                numbufs = 1;
                break;
        default:
-               /* allow ourselves to be swapped once again */
-               PRELE(curproc);
-               return;
-               break; /* NOTREACHED */ 
+               numbufs = 0;
+               break;
        }
 
+       error = 0;
        for (i = 0; i < numbufs; i++) {
                if (mapinfo->bp[i]) {
                        /* unmap the buffer */
@@ -1103,8 +1102,12 @@ cam_periph_unmapmem(union ccb *ccb, struct 
cam_periph_map_info *mapinfo)
                        uma_zfree(pbuf_zone, mapinfo->bp[i]);
                } else {
                        if (dirs[i] != CAM_DIR_OUT) {
-                               copyout(*data_ptrs[i], mapinfo->orig[i],
+                               int error1;
+
+                               error1 = copyout(*data_ptrs[i], 
mapinfo->orig[i],
                                    lengths[i]);
+                               if (error == 0)
+                                       error = error1;
                        }
                        free(*data_ptrs[i], M_CAMPERIPH);
                }
@@ -1115,6 +1118,8 @@ cam_periph_unmapmem(union ccb *ccb, struct 
cam_periph_map_info *mapinfo)
 
        /* allow ourselves to be swapped once again */
        PRELE(curproc);
+
+       return (error);
 }
 
 int
diff --git a/sys/cam/cam_periph.h b/sys/cam/cam_periph.h
index d0f04388b181..ad18ee6b204c 100644
--- a/sys/cam/cam_periph.h
+++ b/sys/cam/cam_periph.h
@@ -180,7 +180,7 @@ void                cam_periph_invalidate(struct cam_periph 
*periph);
 int            cam_periph_mapmem(union ccb *ccb,
                                  struct cam_periph_map_info *mapinfo,
                                  u_int maxmap);
-void           cam_periph_unmapmem(union ccb *ccb,
+int            cam_periph_unmapmem(union ccb *ccb,
                                    struct cam_periph_map_info *mapinfo);
 union ccb      *cam_periph_getccb(struct cam_periph *periph,
                                   uint32_t priority);
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index de3630c35374..2acb106b087c 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -563,11 +563,9 @@ xptdoioctl(struct cdev *dev, u_long cmd, caddr_t addr, int 
flag, struct thread *
                        /*
                         * Map the buffers back into user space.
                         */
-                       cam_periph_unmapmem(inccb, &mapinfo);
+                       error = cam_periph_unmapmem(inccb, &mapinfo);
 
                        inccb->ccb_h.path = old_path;
-
-                       error = 0;
                        break;
                }
                default:
diff --git a/sys/cam/nvme/nvme_da.c b/sys/cam/nvme/nvme_da.c
index 73c385b2fe1c..2dd7c6d4a70b 100644
--- a/sys/cam/nvme/nvme_da.c
+++ b/sys/cam/nvme/nvme_da.c
@@ -437,8 +437,9 @@ ndaioctl(struct disk *dp, u_long cmd, void *data, int fflag,
                 * Tear down mapping and return status.
                 */
                cam_periph_unlock(periph);
-               cam_periph_unmapmem(ccb, &mapinfo);
-               error = cam_ccb_success(ccb) ? 0 : EIO;
+               error = cam_periph_unmapmem(ccb, &mapinfo);
+               if (!cam_ccb_success(ccb))
+                       error = EIO;
 out:
                cam_periph_lock(periph);
                xpt_release_ccb(ccb);
diff --git a/sys/cam/scsi/scsi_pass.c b/sys/cam/scsi/scsi_pass.c
index 5c05ca84bcab..5a24f11e60e2 100644
--- a/sys/cam/scsi/scsi_pass.c
+++ b/sys/cam/scsi/scsi_pass.c
@@ -2236,14 +2236,14 @@ passsendccb(struct cam_periph *periph, union ccb *ccb, 
union ccb *inccb)
        }
 
        cam_periph_unlock(periph);
-       cam_periph_unmapmem(ccb, &mapinfo);
+       error = cam_periph_unmapmem(ccb, &mapinfo);
        cam_periph_lock(periph);
 
        ccb->ccb_h.cbfcnp = NULL;
        ccb->ccb_h.periph_priv = inccb->ccb_h.periph_priv;
        bcopy(ccb, inccb, sizeof(union ccb));
 
-       return(0);
+       return (error);
 }
 
 /*
diff --git a/sys/cam/scsi/scsi_sg.c b/sys/cam/scsi/scsi_sg.c
index 27a0b298fd31..fec3bb157b52 100644
--- a/sys/cam/scsi/scsi_sg.c
+++ b/sys/cam/scsi/scsi_sg.c
@@ -882,7 +882,7 @@ sgsendccb(struct cam_periph *periph, union ccb *ccb)
 {
        struct sg_softc *softc;
        struct cam_periph_map_info mapinfo;
-       int error;
+       int error, error1;
 
        softc = periph->softc;
        bzero(&mapinfo, sizeof(mapinfo));
@@ -907,7 +907,9 @@ sgsendccb(struct cam_periph *periph, union ccb *ccb)
                                  softc->device_stats);
 
        cam_periph_unlock(periph);
-       cam_periph_unmapmem(ccb, &mapinfo);
+       error1 = cam_periph_unmapmem(ccb, &mapinfo);
+       if (error == 0)
+               error = error1;
        cam_periph_lock(periph);
 
        return (error);
diff --git a/sys/cam/scsi/scsi_target.c b/sys/cam/scsi/scsi_target.c
index 5fe123427447..f1c01cab8638 100644
--- a/sys/cam/scsi/scsi_target.c
+++ b/sys/cam/scsi/scsi_target.c
@@ -905,18 +905,29 @@ targreturnccb(struct targ_softc *softc, union ccb *ccb)
        u_ccbh = &descr->user_ccb->ccb_h;
 
        /* Copy out the central portion of the ccb_hdr */
-       copyout(&ccb->ccb_h.retry_count, &u_ccbh->retry_count,
-               offsetof(struct ccb_hdr, periph_priv) -
-               offsetof(struct ccb_hdr, retry_count));
+       error = copyout(&ccb->ccb_h.retry_count, &u_ccbh->retry_count,
+           offsetof(struct ccb_hdr, periph_priv) -
+           offsetof(struct ccb_hdr, retry_count));
+       if (error != 0) {
+               xpt_print(softc->path,
+                   "targreturnccb - CCB header copyout failed (%d)\n", error);
+       }
 
        /* Copy out the rest of the ccb (after the ccb_hdr) */
        ccb_len = targccblen(ccb->ccb_h.func_code) - sizeof(struct ccb_hdr);
-       if (descr->mapinfo.num_bufs_used != 0)
-               cam_periph_unmapmem(ccb, &descr->mapinfo);
-       error = copyout(&ccb->ccb_h + 1, u_ccbh + 1, ccb_len);
-       if (error != 0) {
-               xpt_print(softc->path,
-                   "targreturnccb - CCB copyout failed (%d)\n", error);
+       if (descr->mapinfo.num_bufs_used != 0) {
+               int error1;
+
+               error1 = cam_periph_unmapmem(ccb, &descr->mapinfo);
+               if (error == 0)
+                       error = error1;
+       }
+       if (error == 0) {
+               error = copyout(&ccb->ccb_h + 1, u_ccbh + 1, ccb_len);
+               if (error != 0) {
+                       xpt_print(softc->path,
+                           "targreturnccb - CCB copyout failed (%d)\n", error);
+               }
        }
        /* Free CCB or send back to devq. */
        targfreeccb(softc, ccb);

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