Factor out the logic for mprotecting the memory between two symbols into

a new MI routine _dl_protect_segment(), and use that for protecting the
GOT and--on some archs--the PLT.

Amazing testing turnaround by miod@, who apparently violated relativity
to get back results on some archs as fast as he did

1 files changed, 15 insertions, 39 deletions

diff --git a/libexec/ld.so/m88k/rtld_machine.c b/libexec/ld.so/m88k/rtld_machine.c
index 3d87aab0421..6e21fe1e810 100644
--- a/libexec/ld.so/m88k/rtld_machine.c
+++ b/libexec/ld.so/m88k/rtld_machine.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtld_machine.c,v 1.12 2015/09/01 05:10:43 guenther Exp $	*/
+/*	$OpenBSD: rtld_machine.c,v 1.13 2015/11/02 07:02:53 guenther Exp $	*/
 
 /*
  * Copyright (c) 2013 Miodrag Vallat.
@@ -276,6 +276,7 @@ _dl_md_reloc_got(elf_object_t *object, int lazy)
 	Elf_Addr *pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
 	Elf_Addr ooff;
 	Elf_Addr plt_start, plt_end;
+	size_t plt_size;
 	const Elf_Sym *this;
 
 	if (pltgot == NULL)
@@ -290,28 +291,6 @@ _dl_md_reloc_got(elf_object_t *object, int lazy)
 	if (object->traced)
 		lazy = 1;
 
-	object->got_addr = 0;
-	object->got_size = 0;
-	this = NULL;
-	ooff = _dl_find_symbol("__got_start", &this,
-	    SYM_SEARCH_OBJ | SYM_NOWARNNOTFOUND | SYM_PLT, NULL, object, NULL);
-	if (this != NULL)
-		object->got_addr = ooff + this->st_value;
-
-	this = NULL;
-	ooff = _dl_find_symbol("__got_end", &this,
-	    SYM_SEARCH_OBJ | SYM_NOWARNNOTFOUND | SYM_PLT, NULL, object, NULL);
-	if (this != NULL)
-		object->got_size = ooff + this->st_value  - object->got_addr;
-
-	if (object->got_addr == 0)
-		object->got_start = 0;
-	else {
-		object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz);
-		object->got_size += object->got_addr - object->got_start;
-		object->got_size = ELF_ROUND(object->got_size, _dl_pagesz);
-	}
-
 	/*
 	 * Post-5.3 binaries use dynamic tags to provide the .plt boundaries.
 	 * If the tags are missing, fall back to the special symbol search.
@@ -335,25 +314,23 @@ _dl_md_reloc_got(elf_object_t *object, int lazy)
 		if (this != NULL)
 			plt_end = ooff + this->st_value;
 		else
-			plt_end = 0;
+			plt_start = 0;		/* not enough to go on */
 	} else {
 		plt_start += object->obj_base;
 		plt_end += object->obj_base;
 	}
 
-	if (plt_start == 0) {
-		object->plt_start = 0;
-		object->plt_size = 0;
-	} else {
-		object->plt_start = ELF_TRUNC(plt_start, _dl_pagesz);
-		object->plt_size =
-		    ELF_ROUND(plt_end, _dl_pagesz) - object->plt_start;
+	if (plt_start == 0)
+		plt_size = 0;
+	else {
+		plt_start = ELF_TRUNC(plt_start, _dl_pagesz);
+		plt_size = ELF_ROUND(plt_end, _dl_pagesz) - plt_start;
 
 		/*
 		 * GOT relocation will require PLT to be writeable.
 		 */
 		if (!lazy || object->obj_base != 0)
-			_dl_mprotect((void*)object->plt_start, object->plt_size,
+			_dl_mprotect((void *)plt_start, plt_size,
 			    PROT_READ | PROT_WRITE);
 	}
 
@@ -378,18 +355,17 @@ _dl_md_reloc_got(elf_object_t *object, int lazy)
 		}
 	}
 
-	if (object->got_size != 0) {
-		_dl_mprotect((void*)object->got_start, object->got_size,
-		    PROT_READ);
-	}
-	if (object->plt_size != 0) {
+	/* mprotect the GOT */
+	_dl_protect_segment(object, 0, "__got_start", "__got_end", PROT_READ);
+
+	if (plt_size != 0) {
 		if (!lazy || object->obj_base != 0) {
 			/*
 			 * Force a cache sync on the whole plt here,
 			 * otherwise I$ might have stale information.
 			 */
-			_dl_cacheflush(object->plt_start, object->plt_size);
-			_dl_mprotect((void*)object->plt_start, object->plt_size,
+			_dl_cacheflush(plt_start, plt_size);
+			_dl_mprotect((void *)plt_start, plt_size,
 			    PROT_READ | PROT_EXEC);
 		}
 	}