git: a3acb379bdea - stable/12 - rman: fix overflow in rman_reserve_resource_bound()
Mitchell Horne
mhorne at FreeBSD.org
Mon Oct 4 14:18:16 UTC 2021
The branch stable/12 has been updated by mhorne:
URL: https://cgit.FreeBSD.org/src/commit/?id=a3acb379bdea033ce08b4800cbb5a9c46a673ce1
commit a3acb379bdea033ce08b4800cbb5a9c46a673ce1
Author: Elliott Mitchell <ehem+freebsd at m5p.com>
AuthorDate: 2021-09-27 17:13:19 +0000
Commit: Mitchell Horne <mhorne at FreeBSD.org>
CommitDate: 2021-10-04 14:15:19 +0000
rman: fix overflow in rman_reserve_resource_bound()
If the default range of [0, ~0] is given, then (~0 - 0) + 1 == 0. This
in turn will cause any allocation of non-zero size to fail. Zero-sized
allocations are prohibited, so add a KASSERT to this effect.
History indicates it is part of the original rman code. This bug may in
fact be older than some contributors.
Reviewed by: mhorne
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30280
(cherry picked from commit bcddaadbef5850ed9f040836d3f25ff57138ae28)
---
sys/kern/subr_rman.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sys/kern/subr_rman.c b/sys/kern/subr_rman.c
index 98614b85e32b..4af718695159 100644
--- a/sys/kern/subr_rman.c
+++ b/sys/kern/subr_rman.c
@@ -449,6 +449,8 @@ rman_reserve_resource_bound(struct rman *rm, rman_res_t start, rman_res_t end,
"length %#jx, flags %x, device %s\n", rm->rm_descr, start, end,
count, flags,
dev == NULL ? "<null>" : device_get_nameunit(dev)));
+ KASSERT(count != 0, ("%s: attempted to allocate an empty range",
+ __func__));
KASSERT((flags & RF_FIRSTSHARE) == 0,
("invalid flags %#x", flags));
new_rflags = (flags & ~RF_FIRSTSHARE) | RF_ALLOCATED;
@@ -524,7 +526,7 @@ rman_reserve_resource_bound(struct rman *rm, rman_res_t start, rman_res_t end,
DPRINTF(("truncated region: [%#jx, %#jx]; size %#jx (requested %#jx)\n",
rstart, rend, (rend - rstart + 1), count));
- if ((rend - rstart + 1) >= count) {
+ if ((rend - rstart) >= (count - 1)) {
DPRINTF(("candidate region: [%#jx, %#jx], size %#jx\n",
rstart, rend, (rend - rstart + 1)));
if ((s->r_end - s->r_start + 1) == count) {
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