ref: 09f2ec3bbc9aeb432f4f2be3056ac0dfa74039ac
parent: 081b58a69e5efc2bbf49ee31099372527edb3fa7
author: Ori Bernstein <ori@eigenstate.org>
date: Wed Feb 7 17:33:37 EST 2024
disk/qcow2: fix crash with misaligned sectors When looping over the pages in a misaligned sector, we would null out the disk, rather than simply checking whether the translation was done correctly.
--- a/sys/src/cmd/disk/qcowfs.c
+++ b/sys/src/cmd/disk/qcowfs.c
@@ -463,14 +463,15 @@
rem = len;
while(rem != 0){phys_off = xlate(d, off, nil);
- if(phys_off <= 0)
- d = nil;
+ if(phys_off == -1){+ responderror(r);
+ return;
+ }
cluster_off = off % disk->clustersz;
sz = disk->clustersz - cluster_off;
if(sz > rem)
sz = rem;
-
- if(!d)
+ if(phys_off == 0)
memset(buf, 0, sz);
else
sz = pread(d->fd, buf, sz, phys_off);
--- /dev/null
+++ b/sys/src/cmd/disk/test/basic.rc
@@ -1,0 +1,28 @@
+#!/bin/rc
+
+# read fresh disk
+../$O.qcowfs -n 4294967296 /tmp/qcow
+dd -ibs 389120 -skip 1 -obs 8192 -count 1 < /mnt/qcow/data >/dev/null
+../$O.qcowfs -n 4294967296 /tmp/qcow
+dd -ibs 389120 -skip 1 -obs 15473 -count 1 < /mnt/qcow/data >/dev/null
+
+# write
+../$O.qcowfs -n 4294967296 /tmp/qcow
+dd -ibs 389120 -skip 1 -obs 8192 -count 1 -if /dev/random -of /mnt/qcow/data # start, power of two
+dd -ibs 389120 -skip 1 -obs 15473 -count 1 -if /dev/random -of /mnt/qcow/data # random prime
+dd -ibs 389120 -skip 1 -obs 8192 -seek 524287 -count 1 -if /dev/random -of /mnt/qcow/data # end
+
+# read written disk
+dd -ibs 389120 -skip 1 -obs 8192 -count 1 < /mnt/qcow/data >/dev/null
+dd -ibs 389120 -skip 1 -obs 15473 -count 1 < /mnt/qcow/data >/dev/null
+
+# read and write some data
+cat /bin/cat > /mnt/qcow/data
+sz = `{walk -es /bin/cat}+xhash=`{cat /bin/cat | sha1sum}+rhash=`{read -c $sz /mnt/qcow/data | sha1sum}+if(! ~ $xhash $rhash){+ >[1=2] echo mismatched data
+ exit mishash
+}
+exit ''
--- /dev/null
+++ b/sys/src/cmd/disk/test/mkfile
@@ -1,0 +1,6 @@
+</$objtype/mkfile
+
+TEST=\
+ basic
+
+</sys/src/cmd/mktest