svn commit: r335254 - in head/stand/i386: libi386 zfsboot

[Allan Jude]

Author: allanjude
Date: Sat Jun 16 15:16:02 2018
New Revision: 335254
URL: https://svnweb.freebsd.org/changeset/base/335254

Log:
  Avoid reading past the end of the disk in zfsboot.c and biosdisk.c
  
  The GELI boot code rounds reads up to 4k, since the encrypted sectors are
  4k, and must be decrypted as a unit. With oddball sized disks (almost
  always virtual), this can lead to reading past the end of the disk.
  
  Reviewed by:	imp, tsoome
  Sponsored by:	Klara Systems
  Differential Revision:	https://reviews.freebsd.org/D15844

Modified:
  head/stand/i386/libi386/biosdisk.c
  head/stand/i386/zfsboot/zfsboot.c

Modified: head/stand/i386/libi386/biosdisk.c
==============================================================================
--- head/stand/i386/libi386/biosdisk.c	Sat Jun 16 15:05:05 2018	(r335253)
+++ head/stand/i386/libi386/biosdisk.c	Sat Jun 16 15:16:02 2018	(r335254)
@@ -882,6 +882,12 @@ bd_read(struct disk_devdesc *dev, daddr_t dblk, int bl
 			}
 		}
 
+		if (alignlba + alignblks > BD(dev).bd_sectors) {
+			DEBUG("Shorted read at %llu from %d to %llu blocks",
+			    alignlba, alignblks, BD(dev).bd_sectors - alignlba);
+			alignblks = BD(dev).bd_sectors - alignlba;
+		}
+
 		err = bd_io(dev, alignlba, alignblks, tmpbuf, 0);
 		if (err)
 			return (err);

Modified: head/stand/i386/zfsboot/zfsboot.c
==============================================================================
--- head/stand/i386/zfsboot/zfsboot.c	Sat Jun 16 15:05:05 2018	(r335253)
+++ head/stand/i386/zfsboot/zfsboot.c	Sat Jun 16 15:16:02 2018	(r335254)
@@ -209,6 +209,12 @@ vdev_read(void *xvdev, void *priv, off_t off, void *bu
 		alignnb = roundup2(nb * DEV_BSIZE + diff, DEV_GELIBOOT_BSIZE)
 		    / DEV_BSIZE;
 
+		if (dsk->size > 0 && alignlba + alignnb > dsk->size + dsk->start) {
+			printf("Shortening read at %lld from %d to %lld\n", alignlba,
+			    alignnb, (dsk->size + dsk->start) - alignlba);
+			alignnb = (dsk->size + dsk->start) - alignlba;
+		}
+
 		if (drvread(dsk, dmadat->rdbuf, alignlba, alignnb))
 			return -1;
 #ifdef LOADER_GELI_SUPPORT
@@ -694,7 +700,7 @@ main(void)
     dsk->slice = *(uint8_t *)PTOV(ARGS + 1) + 1;
     dsk->part = 0;
     dsk->start = 0;
-    dsk->size = 0;
+    dsk->size = drvsize_ext(dsk);
 
     bootinfo.bi_version = BOOTINFO_VERSION;
     bootinfo.bi_size = sizeof(bootinfo);
@@ -745,7 +751,7 @@ main(void)
 	dsk->slice = 0;
 	dsk->part = 0;
 	dsk->start = 0;
-	dsk->size = 0;
+	dsk->size = drvsize_ext(dsk);
 	probe_drive(dsk);
     }