From 12978acb3066db738c8c15121e81adbb63739876 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Thu, 26 Nov 2015 19:59:46 +0100 Subject: [PATCH] ldso: fix the dtv update logic in __tls_get_new if two or more threads accessed tls in a dso that was loaded after the threads were created, then __tls_get_new could do out-of-bound memory access (leading to segfault). accidentally byte count was used instead of element count when the new dtv pointer was computed. (dso->new_dtv is (void**).) it is rare that the same dso provides dtv for several threads, the crash was not observed in practice, but possible to trigger. --- src/ldso/dynlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 4648e9a..93e7d67 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -1280,7 +1280,7 @@ void *__tls_get_new(size_t *v) /* Get new DTV space from new DSO if needed */ if (v[0] > (size_t)self->dtv[0]) { void **newdtv = p->new_dtv + - (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1); + (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1); memcpy(newdtv, self->dtv, ((size_t)self->dtv[0]+1) * sizeof(void *)); newdtv[0] = (void *)v[0]; -- 2.7.0