Author: pfg
Date: Wed Aug 22 04:20:20 2018
New Revision: 338179
URL: https://svnweb.freebsd.org/changeset/base/338179
Log:
MFC r337456:
msdosfs: fixes for Undefined Behavior.
These were found by the Undefined Behaviour GsoC project at NetBSD:
Do not change signedness bit with left shift.
While there avoid signed integer overflow.
Address both issues with using unsigned type.
msdosfs_fat.c:512:42, left shift of 1 by 31 places cannot be represented
in type 'int'
msdosfs_fat.c:521:44, left shift of 1 by 31 places cannot be represented
in type 'int'
msdosfs_fat.c:744:14, left shift of 1 by 31 places cannot be represented
in type 'int'
msdosfs_fat.c:744:24, signed integer overflow: -2147483648 - 1 cannot be
represented in type 'int [20]'
msdosfs_fat.c:840:13, left shift of 1 by 31 places cannot be represented
in type 'int'
msdosfs_fat.c:840:36, signed integer overflow: -2147483648 - 1 cannot be
represented in type 'int [20]'
Detected with micro-UBSan in the user mode.
Hinted from: NetBSD (CVS 1.33)
Modified:
stable/11/sys/fs/msdosfs/msdosfs_fat.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/fs/msdosfs/msdosfs_fat.c
==============================================================================
--- stable/11/sys/fs/msdosfs/msdosfs_fat.c Wed Aug 22 04:09:55 2018
(r338178)
+++ stable/11/sys/fs/msdosfs/msdosfs_fat.c Wed Aug 22 04:20:20 2018
(r338179)
@@ -389,7 +389,7 @@ usemap_alloc(struct msdosfsmount *pmp, u_long cn)
KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
== 0, ("Allocating used sector %ld %ld %x", cn, cn % N_INUSEBITS,
(unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
- pmp->pm_inusemap[cn / N_INUSEBITS] |= 1 << (cn % N_INUSEBITS);
+ pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
KASSERT(pmp->pm_freeclustercount > 0, ("usemap_alloc: too little"));
pmp->pm_freeclustercount--;
pmp->pm_flags |= MSDOSFS_FSIMOD;
@@ -410,7 +410,7 @@ usemap_free(struct msdosfsmount *pmp, u_long cn)
KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
!= 0, ("Freeing unused sector %ld %ld %x", cn, cn % N_INUSEBITS,
(unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
- pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1 << (cn % N_INUSEBITS));
+ pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1U << (cn % N_INUSEBITS));
}
int
@@ -773,7 +773,7 @@ clusteralloc1(struct msdosfsmount *pmp, u_long start,
for (cn = newst; cn <= pmp->pm_maxcluster;) {
idx = cn / N_INUSEBITS;
map = pmp->pm_inusemap[idx];
- map |= (1 << (cn % N_INUSEBITS)) - 1;
+ map |= (1U << (cn % N_INUSEBITS)) - 1;
if (map != FULL_RUN) {
cn = idx * N_INUSEBITS + ffs(map ^ FULL_RUN) - 1;
if ((l = chainlength(pmp, cn, count)) >= count)
@@ -790,7 +790,7 @@ clusteralloc1(struct msdosfsmount *pmp, u_long start,
for (cn = 0; cn < newst;) {
idx = cn / N_INUSEBITS;
map = pmp->pm_inusemap[idx];
- map |= (1 << (cn % N_INUSEBITS)) - 1;
+ map |= (1U << (cn % N_INUSEBITS)) - 1;
if (map != FULL_RUN) {
cn = idx * N_INUSEBITS + ffs(map ^ FULL_RUN) - 1;
if ((l = chainlength(pmp, cn, count)) >= count)
@@ -948,7 +948,7 @@ fillinusemap(struct msdosfsmount *pmp)
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);
+ pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
return (0);
}
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