Author: mckusick
Date: Sat Jul 7 19:11:43 2018
New Revision: 336074
URL: https://svnweb.freebsd.org/changeset/base/336074
Log:
Import commit from NetBSD with checkin message:
Avoid Undefined Behavior in ffs_clusteracct()
Change the type of 'bit' variable from int to unsigned int and use
unsigned
values consistently.
sys/ufs/ffs/ffs_subr.c:336:10, shift exponent -1 is negative
Detected with Kernel Undefined Behavior Sanitizer.
Reported by <Harry Pantazis>
Submitted by: Pedro Giffuni
Modified:
head/sys/ufs/ffs/ffs_subr.c
Modified: head/sys/ufs/ffs/ffs_subr.c
==============================================================================
--- head/sys/ufs/ffs/ffs_subr.c Sat Jul 7 19:10:00 2018 (r336073)
+++ head/sys/ufs/ffs/ffs_subr.c Sat Jul 7 19:11:43 2018 (r336074)
@@ -473,7 +473,8 @@ ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_da
int32_t *sump;
int32_t *lp;
u_char *freemapp, *mapp;
- int i, start, end, forw, back, map, bit;
+ int i, start, end, forw, back, map;
+ u_int bit;
if (fs->fs_contigsumsize <= 0)
return;
@@ -495,7 +496,7 @@ ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_da
end = cgp->cg_nclusterblks;
mapp = &freemapp[start / NBBY];
map = *mapp++;
- bit = 1 << (start % NBBY);
+ bit = 1U << (start % NBBY);
for (i = start; i < end; i++) {
if ((map & bit) == 0)
break;
@@ -516,7 +517,7 @@ ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_da
end = -1;
mapp = &freemapp[start / NBBY];
map = *mapp--;
- bit = 1 << (start % NBBY);
+ bit = 1U << (start % NBBY);
for (i = start; i > end; i--) {
if ((map & bit) == 0)
break;
@@ -524,7 +525,7 @@ ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_da
bit >>= 1;
} else {
map = *mapp--;
- bit = 1 << (NBBY - 1);
+ bit = 1U << (NBBY - 1);
}
}
back = start - i;
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