diff options
| -rw-r--r-- | libexec/ld.so/library_mquery.c | 51 |
1 files changed, 20 insertions, 31 deletions
diff --git a/libexec/ld.so/library_mquery.c b/libexec/ld.so/library_mquery.c index a01d43af83e..2eca7e76246 100644 --- a/libexec/ld.so/library_mquery.c +++ b/libexec/ld.so/library_mquery.c @@ -1,4 +1,4 @@ -/* $OpenBSD: library_mquery.c,v 1.58 2017/12/08 05:25:20 deraadt Exp $ */ +/* $OpenBSD: library_mquery.c,v 1.59 2019/01/25 18:13:13 kurt Exp $ */ /* * Copyright (c) 2002 Dale Rahn @@ -235,8 +235,6 @@ retry: void *res; flags = MAP_PRIVATE; - if (LOFF + ld->moff != 0) - flags |= MAP_FIXED | __MAP_NOREPLACE; if (ld->foff < 0) { fd = -1; @@ -247,42 +245,33 @@ retry: foff = ld->foff; } - res = _dl_mmap((void *)(LOFF + ld->moff), ROUND_PG(ld->size), - ld->prot, flags, fd, foff); - if (_dl_mmap_error(res)) { + if (ld == lowld) { /* - * The mapping we wanted isn't free, so we do an - * mquery without MAP_FIXED to get the next free - * mapping, adjust the base mapping address to match - * this free mapping and restart the process again. - * - * XXX - we need some kind of boundary condition - * here, or fix mquery to not run into the stack + * Add PROT_EXEC to force the first allocation in + * EXEC region unless it is writable. */ + int exec = (ld->prot & PROT_WRITE) ? 0 : PROT_EXEC; res = _dl_mquery((void *)(LOFF + ld->moff), - ROUND_PG(ld->size), ld->prot, - flags & ~(MAP_FIXED | __MAP_NOREPLACE), fd, foff); + ROUND_PG(ld->size), ld->prot | exec, flags, + fd, foff); + if (_dl_mmap_error(res)) + goto fail; + lowld->start = res; + } - /* - * If ld == lowld, then ld->start is just a hint and - * thus shouldn't be unmapped. - */ - ld->start = NULL; + res = _dl_mmap((void *)(LOFF + ld->moff), ROUND_PG(ld->size), + ld->prot, flags | MAP_FIXED | __MAP_NOREPLACE, fd, foff); + + if (_dl_mmap_error(res)) { + struct load_list *ll; /* Unmap any mappings that we did get in. */ - for (ld = lowld; ld != NULL; ld = ld->next) { - if (ld->start == NULL) - break; - _dl_munmap(ld->start, ROUND_PG(ld->size)); - ld->start = NULL; + for (ll = lowld; ll != NULL && ll != ld; + ll = ll->next) { + _dl_munmap(ll->start, ROUND_PG(ll->size)); } - /* if the mquery failed, give up */ - if (_dl_mmap_error(res)) - goto fail; - - /* otherwise, reset the start of the base mapping */ - lowld->start = res - ld->moff + lowld->moff; + lowld->start += ROUND_PG(ld->size); goto retry; } |