Date: Mon, 27 Sep 2021 17:39:11 GMT From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: bcddaadbef58 - main - rman: fix overflow in rman_reserve_resource_bound() Message-ID: <202109271739.18RHdBFT068993@gitrepo.freebsd.org>
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The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=bcddaadbef5850ed9f040836d3f25ff57138ae28 commit bcddaadbef5850ed9f040836d3f25ff57138ae28 Author: Elliott Mitchell <ehem+freebsd@m5p.com> AuthorDate: 2021-09-27 17:13:19 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2021-09-27 17:38:26 +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 --- 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 a8f5188e7f54..1bbaff8264ef 100644 --- a/sys/kern/subr_rman.c +++ b/sys/kern/subr_rman.c @@ -445,6 +445,8 @@ 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; @@ -520,7 +522,7 @@ 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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