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* sysdeps/unisx/sysv/linux/dl-execstack.c: Get protection flag
	from memory.
	* elf/dl-load.c (_dl_map_object_from_fd): Add PROT_EXEC flag to
	__stack_flags.
This commit is contained in:
Ulrich Drepper 2004-09-19 02:48:59 +00:00
parent d72433621f
commit dcca3fe25f
3 changed files with 47 additions and 16 deletions
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5
ChangeLog
View File

@ -1,5 +1,10 @@
2004-09-18 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unisx/sysv/linux/dl-execstack.c: Get protection flag
from memory.
* elf/dl-load.c (_dl_map_object_from_fd): Add PROT_EXEC flag to
__stack_flags.
* sysdeps/posix/getaddrinfo.c (gaih_inet): Do not use
gethostbyname3_r if we are not looking for the canonical name.

45
elf/dl-load.c
View File

@ -101,6 +101,9 @@ ELF_PREFERRED_ADDRESS_DATA;
# define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
#endif
extern int __stack_prot attribute_relro attribute_hidden;
/* Type for the buffer we put the ELF header and hopefully the program
header. This buffer does not really have to be too large. In most
cases the program header follows the ELF header directly. If this
@ -1302,6 +1305,35 @@ cannot allocate TLS data structures for initial thread");
goto call_lose;
}
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. We must change the
protection of the variable which contains the flags used in
the mprotect calls. */
#ifdef HAVE_Z_RELRO
if (mode & __RTLD_DLOPEN)
{
uintptr_t p = ((uintptr_t) &__stack_prot) & ~(GLRO(dl_pagesize) - 1);
size_t s = (uintptr_t) &__stack_prot - p + sizeof (int);
__mprotect ((void *) p, s, PROT_READ|PROT_WRITE);
__stack_prot |= PROT_EXEC;
__mprotect ((void *) p, s, PROT_READ);
}
else
#endif
__stack_prot |= PROT_EXEC;
errval = (*GL(dl_make_stack_executable_hook)) (stack_endp);
if (errval)
{
errstring = N_("\
cannot enable executable stack as shared object requires");
goto call_lose;
}
}
if (l->l_info[DT_HASH])
_dl_setup_hash (l);
@ -1344,19 +1376,6 @@ 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)) (stack_endp);
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 (GLRO(dl_profile) != NULL, 0)

13
sysdeps/unix/sysv/linux/dl-execstack.c
View File

@ -28,6 +28,14 @@
#include "kernel-features.h"
int __stack_prot attribute_hidden attribute_relro
#if _STACK_GROWS_DOWN
= PROT_READ|PROT_WRITE|PROT_GROWSDOWN;
#elif _STACK_GROWS_UP
= PROT_READ|PROT_WRITE|PROT_GROWSUP;
#endif
int
internal_function
_dl_make_stack_executable (void **stack_endp)
@ -51,8 +59,7 @@ _dl_make_stack_executable (void **stack_endp)
# endif
{
if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
PROT_READ|PROT_WRITE|PROT_EXEC
|PROT_GROWSDOWN) == 0, 1))
__stack_prot) == 0, 1))
goto return_success;
# if __ASSUME_PROT_GROWSUPDOWN == 0
if (errno == EINVAL)
@ -76,7 +83,7 @@ _dl_make_stack_executable (void **stack_endp)
while (1)
{
if (__mprotect ((void *) page, size,
PROT_READ|PROT_WRITE|PROT_EXEC) == 0)
__stack_prot & ~PROT_GROWSDOWN) == 0)
/* We got this chunk changed; loop to do another chunk below. */
page -= size;
else