diff options
author | truckman <truckman@FreeBSD.org> | 2014-05-05 15:59:31 +0000 |
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committer | truckman <truckman@FreeBSD.org> | 2014-05-05 15:59:31 +0000 |
commit | c163eb4b72ccdf316e1f9e38ad2eeef0b39028a9 (patch) | |
tree | edd80cf263d2dfc52be0d718183dd901941fbeeb | |
parent | 6df58573ce70c6790c4e1ab6c8d99197201097cd (diff) | |
download | FreeBSD-src-c163eb4b72ccdf316e1f9e38ad2eeef0b39028a9.zip FreeBSD-src-c163eb4b72ccdf316e1f9e38ad2eeef0b39028a9.tar.gz |
Avoid unsigned integer overflow which can cause
rman_reserve_resource_bound() to return incorrect results.
Continue the initial search until the first viable region is found.
Add a comment to explain the search termination test.
PR: kern/188534
Reviewed by: jhb (previous version)
MFC after: 1 week
-rw-r--r-- | sys/kern/subr_rman.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/sys/kern/subr_rman.c b/sys/kern/subr_rman.c index e43dfcf..30e97c3 100644 --- a/sys/kern/subr_rman.c +++ b/sys/kern/subr_rman.c @@ -456,7 +456,7 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end, mtx_lock(rm->rm_mtx); for (r = TAILQ_FIRST(&rm->rm_list); - r && r->r_end < start; + r && r->r_end < start + count - 1; r = TAILQ_NEXT(r, r_link)) ; @@ -466,6 +466,11 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end, } amask = (1ul << RF_ALIGNMENT(flags)) - 1; + if (start + amask < start) { + DPRINTF(("start+amask wrapped around\n")); + goto out; + } + /* If bound is 0, bmask will also be 0 */ bmask = ~(bound - 1); /* @@ -473,11 +478,20 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end, */ for (s = r; s; s = TAILQ_NEXT(s, r_link)) { DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end)); - if (s->r_start + count - 1 > end) { + /* + * The resource list is sorted, so there is no point in + * searching further once r_start is too large. + */ + if (s->r_start > end - (count - 1)) { DPRINTF(("s->r_start (%#lx) + count - 1> end (%#lx)\n", s->r_start, end)); break; } + if (s->r_start + amask < s->r_start) { + DPRINTF(("s->r_start (%#lx) + amask (%#lx) wrapped\n", + s->r_start, amask)); + break; + } if (s->r_flags & RF_ALLOCATED) { DPRINTF(("region is allocated\n")); continue; |