From 6c5cad2aa56745302c1d42d2c8baf6424d29c0f3 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 22 Sep 2015 23:41:41 +0000 Subject: fix dlsym RTLD_NEXT behavior for fdpic lookup the dso an address falls in based on the loadmap and not just a base/length. fix the main app's fake loadmap used when loaded by a non-fdpic-aware loader so that it does not cover the whole memory space. function descriptor addresses are also matched for future use by dladdr, but reverse lookups of function descriptors via dladdr have not been implemented yet. some revisions may be needed in the future once reclaim_gaps supports fdpic, so that function descriptors allocated in reclaimed heap space do not get detected as belonging to the module whose gaps they were allocated in. --- src/ldso/dynlink.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) (limited to 'src/ldso') diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 0c3b36ce..cab30089 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -1543,8 +1543,10 @@ _Noreturn void __dls3(size_t *sp) if (!app.loadmap) { app.loadmap = (void *)&app_dummy_loadmap; app.loadmap->nsegs = 1; - app.loadmap->segs[0].addr = (size_t)app.base; - app.loadmap->segs[0].p_memsz = -1; + app.loadmap->segs[0].addr = (size_t)app.map; + app.loadmap->segs[0].p_vaddr = (size_t)app.map + - (size_t)app.base; + app.loadmap->segs[0].p_memsz = app.map_len; } argv[-3] = (void *)app.loadmap; } @@ -1738,6 +1740,28 @@ static int invalid_dso_handle(void *h) return 1; } +static void *addr2dso(size_t a) +{ + struct dso *p; + for (p=head; p; p=p->next) { + if (DL_FDPIC && p->loadmap) { + size_t i; + for (i=0; iloadmap->nsegs; i++) { + if (a-p->loadmap->segs[i].p_vaddr + < p->loadmap->segs[i].p_memsz) + return p; + } + i = count_syms(p); + if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs)) + return p; + } else { + if (a-(size_t)p->map < p->map_len) + return p; + } + } + return 0; +} + void *__tls_get_addr(size_t *); static void *do_dlsym(struct dso *p, const char *s, void *ra) @@ -1749,7 +1773,7 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra) if (p == RTLD_DEFAULT) { p = head; } else if (p == RTLD_NEXT) { - for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); + p = addr2dso((size_t)ra); if (!p) p=head; p = p->next; } @@ -1806,7 +1830,7 @@ int __dladdr(const void *addr, Dl_info *info) char *bestname; pthread_rwlock_rdlock(&lock); - for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next); + p = addr2dso((size_t)addr); pthread_rwlock_unlock(&lock); if (!p) return 0; -- cgit 1.4.1