From ecdeaac05f73c29eca92eecd55ad4fb8513c7771 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Tue, 23 Sep 2003 12:06:48 +0000 Subject: 2003-09-23 Roland McGrath * sysdeps/generic/ldsodefs.h (struct rtld_global): Add _dl_stack_flags and _dl_make_stack_executable_hook. Declare _dl_make_stack_executable. * elf/rtld.c (_rtld_global): Add initializer for _dl_stack_flags. (dl_main): Reset _dl_stack_flags according to PT_GNU_STACK phdr. Initialize _dl_make_stack_executable_hook. * elf/dl-support.c: Define those new variables. (_dl_non_dynamic_init): Scan phdrs for PT_GNU_STACK. (_dl_phdr): Fix type. * elf/dl-load.c (_dl_map_object_from_fd): Grok PT_GNU_STACK phdr and enable execute permission for the stack if necessary. * sysdeps/generic/dl-execstack.c: New file. * elf/Makefile (dl-routines): Add it. * elf/Versions (ld: GLIBC_PRIVATE): Add _dl_make_stack_executable. * sysdeps/unix/sysv/linux/dl-execstack.c: New file. --- elf/dl-load.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'elf/dl-load.c') diff --git a/elf/dl-load.c b/elf/dl-load.c index 249ef84639..0b6e96f998 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -904,6 +904,9 @@ _dl_map_object_from_fd (const char *name, int fd, struct filebuf *fbp, } } + /* Presumed absent PT_GNU_STACK. */ + uint_fast16_t stack_flags = PF_R|PF_W|PF_X; + { /* Scan the program header table, collecting its load commands. */ struct loadcmd @@ -1058,6 +1061,10 @@ cannot allocate TLS data structures for initial thread"); errstring = N_("cannot handle TLS data"); goto call_lose; break; + + case PT_GNU_STACK: + stack_flags = ph->p_flags; + break; } if (__builtin_expect (nloadcmds == 0, 0)) @@ -1334,6 +1341,19 @@ cannot allocate TLS data structures for initial thread"); l->l_dev = st.st_dev; l->l_ino = st.st_ino; + if (__builtin_expect ((stack_flags &~ GL(dl_stack_flags)) & PF_X, 0)) + { + /* The stack is presently not executable, but this module + requires that it be executable. */ + errval = (*GL(dl_make_stack_executable_hook)) (); + if (errval) + { + errstring = N_("\ +cannot enable executable stack as shared object requires"); + goto call_lose; + } + } + /* When we profile the SONAME might be needed for something else but loading. Add it right away. */ if (__builtin_expect (GL(dl_profile) != NULL, 0) -- cgit 1.4.1