From a6eef2edb3dada9ee1a0765dd7901d0a988f30ce Mon Sep 17 00:00:00 2001 From: Carmelo Amoroso Date: Fri, 16 Nov 2007 14:32:35 +0000 Subject: If uClibc's ld.so encounters text relocations in a shared library - one containing an object built without -fpic/-fPIC - then: * If __FORCE_SHAREABLE_TEXT_SEGMENTS__, then it gives an error "Can't modify %s's text section. Use GCC option -fPIC for shared objects, please.\n" and exits. * Otherwise, it makes the library's pages writable and relocates it. If it encounters text relocations in a position-independent executable - one containing an object built without -fpie/-fPIE/-fpic/-fPIC - then: * If __FORCE_SHAREABLE_TEXT_SEGMENTS__, it does nothing about making the pages writable, leading to a crash. * Otherwise, the loop to make the pages writable uses the same variable ppnt as used in an outer loop, messing up that outer loop and also causing a crash. This patch fixes both cases, by giving an error if __FORCE_SHAREABLE_TEXT_SEGMENTS__ and saving and restoring ppnt otherwise. Tested in both cases on ARM EABI. Joseph S. Myers joseph@codesourcery.com --- ldso/ldso/ldso.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'ldso/ldso/ldso.c') diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c index e1101bd57..3a5fc14f5 100644 --- a/ldso/ldso/ldso.c +++ b/ldso/ldso/ldso.c @@ -286,6 +286,7 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, _dl_debug_early("calling mprotect on the application program\n"); /* Now cover the application program. */ if (app_tpnt->dynamic_info[DT_TEXTREL]) { + ElfW(Phdr) *ppnt_outer = ppnt; ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val; for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) { if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W)) @@ -294,6 +295,12 @@ void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr, (unsigned long) ppnt->p_filesz, PROT_READ | PROT_WRITE | PROT_EXEC); } + ppnt = ppnt_outer; + } +#else + if (app_tpnt->dynamic_info[DT_TEXTREL]) { + _dl_dprintf(_dl_debug_file, "Can't modify application's text section; use the GCC option -fPIE for position-independent executables.\n"); + _dl_exit(1); } #endif -- cgit v1.2.3