Author: kib
Date: Fri Nov 11 20:06:07 2016
New Revision: 308551
URL: https://svnweb.freebsd.org/changeset/base/308551
Log:
MFC r308024:
Ensure that cluster allocations never allocate clusters outside the
volume limits.
Modified:
stable/10/sys/fs/msdosfs/msdosfs_fat.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/fs/msdosfs/msdosfs_fat.c
==============================================================================
--- stable/10/sys/fs/msdosfs/msdosfs_fat.c Fri Nov 11 20:04:19 2016
(r308550)
+++ stable/10/sys/fs/msdosfs/msdosfs_fat.c Fri Nov 11 20:06:07 2016
(r308551)
@@ -401,6 +401,8 @@ usemap_alloc(pmp, cn)
MSDOSFS_ASSERT_MP_LOCKED(pmp);
+ KASSERT(cn <= pmp->pm_maxcluster, ("cn too large %lu %lu", cn,
+ pmp->pm_maxcluster));
KASSERT((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0,
("usemap_alloc on ro msdosfs mount"));
KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
@@ -419,6 +421,9 @@ usemap_free(pmp, cn)
{
MSDOSFS_ASSERT_MP_LOCKED(pmp);
+
+ KASSERT(cn <= pmp->pm_maxcluster, ("cn too large %lu %lu", cn,
+ pmp->pm_maxcluster));
KASSERT((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0,
("usemap_free on ro msdosfs mount"));
pmp->pm_freeclustercount++;
@@ -672,6 +677,8 @@ chainlength(pmp, start, count)
MSDOSFS_ASSERT_MP_LOCKED(pmp);
+ if (start > pmp->pm_maxcluster)
+ return (0);
max_idx = pmp->pm_maxcluster / N_INUSEBITS;
idx = start / N_INUSEBITS;
start %= N_INUSEBITS;
@@ -679,11 +686,18 @@ chainlength(pmp, start, count)
map &= ~((1 << start) - 1);
if (map) {
len = ffs(map) - 1 - start;
- return (len > count ? count : len);
+ len = MIN(len, count);
+ if (start + len > pmp->pm_maxcluster)
+ len = pmp->pm_maxcluster - start + 1;
+ return (len);
}
len = N_INUSEBITS - start;
- if (len >= count)
- return (count);
+ if (len >= count) {
+ len = count;
+ if (start + len > pmp->pm_maxcluster)
+ len = pmp->pm_maxcluster - start + 1;
+ return (len);
+ }
while (++idx <= max_idx) {
if (len >= count)
break;
@@ -694,7 +708,10 @@ chainlength(pmp, start, count)
}
len += N_INUSEBITS;
}
- return (len > count ? count : len);
+ len = MIN(len, count);
+ if (start + len > pmp->pm_maxcluster)
+ len = pmp->pm_maxcluster - start + 1;
+ return (len);
}
/*
@@ -961,6 +978,11 @@ fillinusemap(pmp)
}
if (bp != NULL)
brelse(bp);
+
+ for (cn = pmp->pm_maxcluster + 1; cn < (pmp->pm_maxcluster +
+ N_INUSEBITS) / N_INUSEBITS; cn++)
+ pmp->pm_inusemap[cn / N_INUSEBITS] |= 1 << (cn % N_INUSEBITS);
+
return (0);
}
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