svn commit: r268968 - stable/10/sbin/fsck_msdosfs
Pedro F. Giffuni
pfg at FreeBSD.org
Mon Jul 21 23:23:21 UTC 2014
Author: pfg
Date: Mon Jul 21 23:23:20 2014
New Revision: 268968
URL: http://svnweb.freebsd.org/changeset/base/268968
Log:
MFC r268632:
fsck_msdosfs: Assorted fixes from other BSDs.
When truncating cluster chains fix the length of the cluster head.
http://marc.info/?t=140304310700005&r=1&w=2
Avoid infinite loops in cluster chain linked lists.
http://marc.info/?l=openbsd-tech&m=140275150804337&w=2
Avoid off-by-one on FAT12 filesystems.
http://marc.info/?l=openbsd-tech&m=140234174104724&w=2
Obtained from: NetBSD (from OpenBSD)
Modified:
stable/10/sbin/fsck_msdosfs/dir.c
stable/10/sbin/fsck_msdosfs/fat.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sbin/fsck_msdosfs/dir.c
==============================================================================
--- stable/10/sbin/fsck_msdosfs/dir.c Mon Jul 21 23:00:26 2014 (r268967)
+++ stable/10/sbin/fsck_msdosfs/dir.c Mon Jul 21 23:23:20 2014 (r268968)
@@ -419,13 +419,14 @@ checksize(struct bootblock *boot, struct
fullpath(dir));
if (ask(1, "Drop superfluous clusters")) {
cl_t cl;
- u_int32_t sz = 0;
+ u_int32_t sz, len;
- for (cl = dir->head; (sz += boot->ClusterSize) <
- dir->size;)
+ for (cl = dir->head, len = sz = 0;
+ (sz += boot->ClusterSize) < dir->size; len++)
cl = fat[cl].next;
clearchain(boot, fat, fat[cl].next);
fat[cl].next = CLUST_EOF;
+ fat[dir->head].length = len;
return FSFATMOD;
} else
return FSERROR;
Modified: stable/10/sbin/fsck_msdosfs/fat.c
==============================================================================
--- stable/10/sbin/fsck_msdosfs/fat.c Mon Jul 21 23:00:26 2014 (r268967)
+++ stable/10/sbin/fsck_msdosfs/fat.c Mon Jul 21 23:23:20 2014 (r268968)
@@ -436,7 +436,15 @@ tryclear(struct bootblock *boot, struct
clearchain(boot, fat, head);
return FSFATMOD;
} else if (ask(0, "Truncate")) {
+ uint32_t len;
+ cl_t p;
+
+ for (p = head, len = 0;
+ p >= CLUST_FIRST && p < boot->NumClusters;
+ p = fat[p].next, len++)
+ continue;
*truncp = CLUST_EOF;
+ fat[head].length = len;
return FSFATMOD;
} else
return FSERROR;
@@ -465,7 +473,8 @@ checkfat(struct bootblock *boot, struct
/* follow the chain and mark all clusters on the way */
for (len = 0, p = head;
- p >= CLUST_FIRST && p < boot->NumClusters;
+ p >= CLUST_FIRST && p < boot->NumClusters &&
+ fat[p].head != head;
p = fat[p].next) {
fat[p].head = head;
len++;
@@ -486,10 +495,10 @@ checkfat(struct bootblock *boot, struct
continue;
/* follow the chain to its end (hopefully) */
- for (p = head;
+ for (len = fat[head].length, p = head;
(n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters;
p = n)
- if (fat[n].head != head)
+ if (fat[n].head != head || len-- < 2)
break;
if (n >= CLUST_EOFS)
continue;
@@ -497,14 +506,20 @@ checkfat(struct bootblock *boot, struct
if (n == CLUST_FREE || n >= CLUST_RSRVD) {
pwarn("Cluster chain starting at %u ends with cluster marked %s\n",
head, rsrvdcltype(n));
+clear:
ret |= tryclear(boot, fat, head, &fat[p].next);
continue;
}
if (n < CLUST_FIRST || n >= boot->NumClusters) {
pwarn("Cluster chain starting at %u ends with cluster out of range (%u)\n",
- head, n);
- ret |= tryclear(boot, fat, head, &fat[p].next);
- continue;
+ head, n);
+ goto clear;
+ }
+ if (head == fat[n].head) {
+ pwarn("Cluster chain starting at %u loops at cluster %u\n",
+
+ head, p);
+ goto clear;
}
pwarn("Cluster chains starting at %u and %u are linked at cluster %u\n",
head, fat[n].head, n);
@@ -621,13 +636,15 @@ writefat(int fs, struct bootblock *boot,
default:
if (fat[cl].next == CLUST_FREE)
boot->NumFree++;
- if (cl + 1 < boot->NumClusters
- && fat[cl + 1].next == CLUST_FREE)
- boot->NumFree++;
*p++ = (u_char)fat[cl].next;
- *p++ = (u_char)((fat[cl].next >> 8) & 0xf)
- |(u_char)(fat[cl+1].next << 4);
- *p++ = (u_char)(fat[++cl].next >> 4);
+ *p = (u_char)((fat[cl].next >> 8) & 0xf);
+ cl++;
+ if (cl >= boot->NumClusters)
+ break;
+ if (fat[cl].next == CLUST_FREE)
+ boot->NumFree++;
+ *p++ |= (u_char)(fat[cl + 1].next << 4);
+ *p++ = (u_char)(fat[cl + 1].next >> 4);
break;
}
}
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