Page MenuHomeFreeBSD
Files F112532163

D46915.id144213.diff
No OneTemporary
Actions

D46915.id144213.diff
View Options

diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -888,7 +888,8 @@
ngrp = *ngrpp;
}
newcred = crget();
- crextend(newcred, ngrp);
+ if (ngrp != 0)
+ crextend(newcred, ngrp);
PROC_LOCK(p);
oldcred = crcopysafe(p, newcred);
@@ -2180,6 +2181,11 @@
bcopy(&src->cr_startcopy, &dest->cr_startcopy,
(unsigned)((caddr_t)&src->cr_endcopy -
(caddr_t)&src->cr_startcopy));
+ /*
+ * Avoid an assertion in crsetgroups() -> crextend(). To be removed as
+ * 'cr_ngroups' is moved out of the bcopied area.
+ */
+ dest->cr_ngroups = 0;
dest->cr_flags = src->cr_flags;
crsetgroups(dest, src->cr_ngroups, src->cr_groups);
uihold(dest->cr_uidinfo);
@@ -2304,45 +2310,44 @@
}
/*
- * Extend the passed in credential to hold n items.
+ * Extend the passed-in credentials to hold n groups.
+ *
+ * Must not be called after groups have been set.
*/
void
crextend(struct ucred *cr, int n)
{
- int cnt;
+ int nbytes;
MPASS2(cr->cr_ref == 1, "'cr_ref' must be 1 (referenced, unshared)");
+ MPASS2(cr->cr_ngroups == 0, "groups on 'cr' already set!");
+ groups_check_positive_len(n);
+ groups_check_max_len(n);
- /* Truncate? */
if (n <= cr->cr_agroups)
return;
- /*
- * We extend by 2 each time since we're using a power of two
- * allocator until we need enough groups to fill a page.
- * Once we're allocating multiple pages, only allocate as many
- * as we actually need. The case of processes needing a
- * non-power of two number of pages seems more likely than
- * a real world process that adds thousands of groups one at a
- * time.
- */
- if ( n < PAGE_SIZE / sizeof(gid_t) ) {
- if (cr->cr_agroups == 0)
- cnt = MAX(1, MINALLOCSIZE / sizeof(gid_t));
- else
- cnt = cr->cr_agroups * 2;
+ nbytes = n * sizeof(gid_t);
- while (cnt < n)
- cnt *= 2;
+ /*
+ * We allocate a power of 2 larger than 'nbytes', except when that
+ * exceeds PAGE_SIZE, in which case we allocate the right multiple of
+ * pages. We assume PAGE_SIZE is a power of 2 (the call to roundup2()
+ * below) but do not need to for sizeof(gid_t).
+ */
+ if (nbytes < PAGE_SIZE) {
+ if (!powerof2(nbytes))
+ /* fls() returns a bit index starting at 1. */
+ nbytes = 1 << fls(nbytes);
} else
- cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t));
+ nbytes = roundup2(nbytes, PAGE_SIZE);
/* Free the old array. */
if (cr->cr_groups != cr->cr_smallgroups)
free(cr->cr_groups, M_CRED);
- cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO);
- cr->cr_agroups = cnt;
+ cr->cr_groups = malloc(nbytes, M_CRED, M_WAITOK | M_ZERO);
+ cr->cr_agroups = nbytes / sizeof(gid_t);
}
#ifdef INVARIANTS

File Metadata

Mime Type
text/plain
Expires
Thu, Mar 20, 10:58 AM (16 h, 23 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
17229694
Default Alt Text
D46915.id144213.diff (2 KB)

Event Timeline