[PATCH] elf: early conversion of elf p_flags to mprotect flags
Cupertino Miranda
cupertino.miranda@oracle.com
Wed Jun 11 15:34:14 GMT 2025
PING.
On 04-06-2025 16:58, Cupertino Miranda wrote:
> PING! :)
>
> On 14-05-2025 16:18, Cupertino Miranda wrote:
>> Hi everyone,
>>
>> This patch is related to a change requested by Florian in respect to
>> adding support for MTE stack mode, to which stacks in general needed to
>> be protected with PROT_MTE.
>>
>> Both the files dl-mmap-prot.[ch] and the function name __pf_to_prot,
>> should likely be renamed. Please advise.
>>
>> No regressions for x86-64.
>>
>> Looking forward to your comments.
>>
>> Cheers,
>> Cupertino
>>
>> This patch replaces _dl_stack_flags global variable by
>> _dl_stack_prot_flags.
>> The advantage is that any convertion from p_flags to final used mprotect
>> flags occurs at loading of p_flags. It avoids repeated spurious
>> convertions of _dl_stack_flags, for example in allocate_thread_stack.
>>
>> This modification was suggested in:
>> https://sourceware.org/pipermail/libc-alpha/2025-March/165537.html
>> ---
>> elf/Makefile | 4 ++-
>> elf/dl-execstack-tunable.c | 2 +-
>> elf/dl-load.c | 20 ++++---------
>> elf/dl-mmap-prot.c | 41 ++++++++++++++++++++++++++
>> elf/dl-mmap-prot.h | 26 ++++++++++++++++
>> elf/dl-support.c | 7 ++---
>> elf/rtld.c | 5 +++-
>> nptl/allocatestack.c | 12 ++------
>> support/support_stack_alloc.c | 9 +++---
>> sysdeps/alpha/stackinfo.h | 6 ++--
>> sysdeps/arm/stackinfo.h | 6 ++--
>> sysdeps/generic/ldsodefs.h | 1 +
>> sysdeps/generic/stackinfo.h | 2 +-
>> sysdeps/hppa/stackinfo.h | 6 ++--
>> sysdeps/i386/stackinfo.h | 6 ++--
>> sysdeps/m68k/stackinfo.h | 6 ++--
>> sysdeps/mach/htl/pt-stack-alloc.c | 2 +-
>> sysdeps/mach/hurd/dl-execstack.c | 2 +-
>> sysdeps/microblaze/stackinfo.h | 6 ++--
>> sysdeps/mips/stackinfo.h | 6 ++--
>> sysdeps/or1k/stackinfo.h | 6 ++--
>> sysdeps/powerpc/powerpc32/stackinfo.h | 4 +--
>> sysdeps/s390/stackinfo.h | 6 ++--
>> sysdeps/sh/stackinfo.h | 6 ++--
>> sysdeps/sparc/stackinfo.h | 6 ++--
>> sysdeps/unix/sysv/linux/dl-execstack.c | 2 +-
>> sysdeps/unix/sysv/linux/spawni.c | 5 +---
>> sysdeps/x86_64/stackinfo.h | 6 ++--
>> 28 files changed, 133 insertions(+), 83 deletions(-)
>> create mode 100644 elf/dl-mmap-prot.c
>> create mode 100644 elf/dl-mmap-prot.h
>>
>> diff --git a/elf/Makefile b/elf/Makefile
>> index ed1b0223da..a2e592b50f 100644
>> --- a/elf/Makefile
>> +++ b/elf/Makefile
>> @@ -69,6 +69,7 @@ dl-routines = \
>> dl-lookup-direct \
>> dl-minimal-malloc \
>> dl-misc \
>> + dl-mmap-prot \
>> dl-object \
>> dl-open \
>> dl-origin \
>> @@ -139,6 +140,7 @@ rtld-routines = \
>> dl-hwcaps_split \
>> dl-libc_freeres \
>> dl-minimal \
>> + dl-mmap-prot \
>> dl-mutex \
>> dl-profile \
>> dl-sysdep \
>> @@ -2154,7 +2156,7 @@ $(objpfx)execstack-default: $(first-word
>> $(wildcard $(sysdirs:%=%/stackinfo.h)))
>> $(make-target-directory)
>> { echo '#include <elf.h>'; \
>> echo '#include <stackinfo.h>'; \
>> - echo '#if (DEFAULT_STACK_PERMS & PF_X) == 0'; \
>> + echo '#if (DEFAULT_STACK_PROT_PERMS & PROT_EXEC) == 0'; \
>> echo '@@@execstack-no@@@'; \
>> echo '#else'; \
>> echo '@@@execstack-yes@@@'; \
>> diff --git a/elf/dl-execstack-tunable.c b/elf/dl-execstack-tunable.c
>> index e3b638aeaa..b2511ea031 100644
>> --- a/elf/dl-execstack-tunable.c
>> +++ b/elf/dl-execstack-tunable.c
>> @@ -25,7 +25,7 @@ _dl_handle_execstack_tunable (void)
>> switch (TUNABLE_GET (glibc, rtld, execstack, int32_t, NULL))
>> {
>> case stack_tunable_mode_disable:
>> - if ((__glibc_unlikely (GL(dl_stack_flags)) & PF_X))
>> + if ((__glibc_unlikely (GL(dl_stack_prot_flags)) & PROT_EXEC))
>> _dl_fatal_printf (
>> "Fatal glibc error: executable stack is not allowed\n");
>> break;
>> diff --git a/elf/dl-load.c b/elf/dl-load.c
>> index bf29ec725d..6aae07b9f0 100644
>> --- a/elf/dl-load.c
>> +++ b/elf/dl-load.c
>> @@ -74,6 +74,7 @@ struct filebuf
>> #include <dl-unmap-segments.h>
>> #include <dl-machine-reject-phdr.h>
>> #include <dl-prop.h>
>> +#include <dl-mmap-prot.h>
>> #include <not-cancel.h>
>> #include <endian.h>
>> @@ -1096,7 +1097,7 @@ _dl_map_object_from_fd (const char *name, const
>> char *origname, int fd,
>> /* On most platforms presume that PT_GNU_STACK is absent and the
>> stack is
>> * executable. Other platforms default to a nonexecutable stack
>> and don't
>> * need PT_GNU_STACK to do so. */
>> - unsigned int stack_flags = DEFAULT_STACK_PERMS;
>> + unsigned int stack_flags = DEFAULT_STACK_PROT_PERMS;
>> {
>> /* Scan the program header table, collecting its load commands. */
>> @@ -1171,18 +1172,7 @@ _dl_map_object_from_fd (const char *name, const
>> char *origname, int fd,
>> DIAG_POP_NEEDS_COMMENT;
>> /* Optimize a common case. */
>> -#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC)
>> == 7
>> - c->prot = (PF_TO_PROT
>> - >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
>> -#else
>> - c->prot = 0;
>> - if (ph->p_flags & PF_R)
>> - c->prot |= PROT_READ;
>> - if (ph->p_flags & PF_W)
>> - c->prot |= PROT_WRITE;
>> - if (ph->p_flags & PF_X)
>> - c->prot |= PROT_EXEC;
>> -#endif
>> + c->prot = __pf_to_prot (ph->p_flags);
>> break;
>> case PT_TLS:
>> @@ -1219,7 +1209,7 @@ _dl_map_object_from_fd (const char *name, const
>> char *origname, int fd,
>> break;
>> case PT_GNU_STACK:
>> - stack_flags = ph->p_flags;
>> + stack_flags = __pf_to_prot (ph->p_flags);
>> break;
>> case PT_GNU_RELRO:
>> @@ -1319,7 +1309,7 @@ _dl_map_object_from_fd (const char *name, const
>> char *origname, int fd,
>> /* Adjust the PT_PHDR value by the runtime load address. */
>> l->l_phdr = (ElfW(Phdr) *) ((ElfW(Addr)) l->l_phdr + l->l_addr);
>> - if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_flags)) & PF_X))
>> + if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_prot_flags)) &
>> PROT_EXEC))
>> {
>> /* The stack is presently not executable, but this module
>> requires that it be executable. Only tries to change the
>> diff --git a/elf/dl-mmap-prot.c b/elf/dl-mmap-prot.c
>> new file mode 100644
>> index 0000000000..6b665d84d4
>> --- /dev/null
>> +++ b/elf/dl-mmap-prot.c
>> @@ -0,0 +1,41 @@
>> +/* Convertion from elf p_flags to mmap prot ones.
>> + Copyright (C) 2025 Free Software Foundation, Inc.
>> + This file is part of the GNU C Library.
>> +
>> + The GNU C Library is free software; you can redistribute it and/or
>> + modify it under the terms of the GNU Lesser General Public
>> + License as published by the Free Software Foundation; either
>> + version 2.1 of the License, or (at your option) any later version.
>> +
>> + The GNU C Library is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> + Lesser General Public License for more details.
>> +
>> + You should have received a copy of the GNU Lesser General Public
>> + License along with the GNU C Library; if not, see
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +#include <dl-mmap-prot.h>
>> +#include <ldsodefs.h>
>> +#include <sys/mman.h>
>> +#include <stackinfo.h>
>> +
>> +int _dl_stack_prot_flags = DEFAULT_STACK_PROT_PERMS;
>> +
>> +int
>> +__pf_to_prot (ElfW(Word) value)
>> +{
>> +#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC)
>> == 7
>> + return (PF_TO_PROT >> ((value & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
>> +#else
>> + ElfW(Word) ret = 0;
>> + if (value & PF_R)
>> + ret |= PROT_READ;
>> + if (value & PF_W)
>> + ret |= PROT_WRITE;
>> + if (value & PF_X)
>> + ret |= PROT_EXEC;
>> + return ret;
>> +#endif
>> +}
>> diff --git a/elf/dl-mmap-prot.h b/elf/dl-mmap-prot.h
>> new file mode 100644
>> index 0000000000..94286e598f
>> --- /dev/null
>> +++ b/elf/dl-mmap-prot.h
>> @@ -0,0 +1,26 @@
>> +/* Convertion from elf p_flags to mmap prot ones.
>> + Copyright (C) 2025 Free Software Foundation, Inc.
>> + This file is part of the GNU C Library.
>> +
>> + The GNU C Library is free software; you can redistribute it and/or
>> + modify it under the terms of the GNU Lesser General Public
>> + License as published by the Free Software Foundation; either
>> + version 2.1 of the License, or (at your option) any later version.
>> +
>> + The GNU C Library is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> + Lesser General Public License for more details.
>> +
>> + You should have received a copy of the GNU Lesser General Public
>> + License along with the GNU C Library; if not, see
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +#ifndef _DL_MMAP_PROT_H
>> +#define _DL_MMAP_PROT_H
>> +
>> +#include <link.h>
>> +
>> +int __pf_to_prot (ElfW(Word) value);
>> +
>> +#endif /* _DL_MMAP_PROT_H */
>> diff --git a/elf/dl-support.c b/elf/dl-support.c
>> index 7b2a1c35d5..2484fa83e4 100644
>> --- a/elf/dl-support.c
>> +++ b/elf/dl-support.c
>> @@ -45,6 +45,7 @@
>> #include <array_length.h>
>> #include <dl-symbol-redir-ifunc.h>
>> #include <dl-tunables.h>
>> +#include <dl-mmap-prot.h>
>> extern char *__progname;
>> char **_dl_argv = &__progname; /* This is checked for some error
>> messages. */
>> @@ -166,10 +167,6 @@ enum dso_sort_algorithm _dl_dso_sort_algo;
>> /* The value of the FPU control word the kernel will preset in
>> hardware. */
>> fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
>> -/* Prevailing state of the stack. Generally this includes PF_X,
>> indicating it's
>> - * executable but this isn't true for all platforms. */
>> -ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
>> -
>> #if PTHREAD_IN_LIBC
>> list_t _dl_stack_used;
>> list_t _dl_stack_user;
>> @@ -322,7 +319,7 @@ _dl_non_dynamic_init (void)
>> {
>> /* Check if the stack is nonexecutable. */
>> case PT_GNU_STACK:
>> - _dl_stack_flags = ph->p_flags;
>> + _dl_stack_prot_flags = __pf_to_prot (ph->p_flags);
>> break;
>> case PT_GNU_RELRO:
>> diff --git a/elf/rtld.c b/elf/rtld.c
>> index 3af8ee63c3..fb76521c27 100644
>> --- a/elf/rtld.c
>> +++ b/elf/rtld.c
>> @@ -52,6 +52,7 @@
>> #include <dl-find_object.h>
>> #include <dl-audit-check.h>
>> #include <dl-call_tls_init_tp.h>
>> +#include <dl-mmap-prot.h>
>> #include <assert.h>
>> @@ -322,7 +323,7 @@ struct rtld_global _rtld_global =
>> #include <dl-procruntime.c>
>> /* Generally the default presumption without further information
>> is an
>> * executable stack but this is not true for all platforms. */
>> - ._dl_stack_flags = DEFAULT_STACK_PERMS,
>> + ._dl_stack_prot_flags = DEFAULT_STACK_PROT_PERMS,
>> #ifdef _LIBC_REENTRANT
>> ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
>> ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
>> @@ -1197,6 +1198,7 @@ rtld_setup_main_map (struct link_map *main_map)
>> case PT_GNU_STACK:
>> GL(dl_stack_flags) = ph->p_flags;
>> + GL(dl_stack_prot_flags) = __pf_to_prot (ph->p_flags);
>> break;
>> case PT_GNU_RELRO:
>> @@ -1502,6 +1504,7 @@ dl_main (const ElfW(Phdr) *phdr,
>> if (ph->p_type == PT_GNU_STACK)
>> {
>> GL(dl_stack_flags) = ph->p_flags;
>> + GL(dl_stack_prot_flags) = __pf_to_prot (ph->p_flags);
>> break;
>> }
>> diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
>> index 800ca89720..4c2aacdd10 100644
>> --- a/nptl/allocatestack.c
>> +++ b/nptl/allocatestack.c
>> @@ -150,17 +150,11 @@ get_cached_stack (size_t *sizep, void **memp)
>> and fallback to ALLOCATE_GUARD_PROT_NONE if the madvise call
>> fails. */
>> static int allocate_stack_mode = ALLOCATE_GUARD_MADV_GUARD;
>> -static inline int stack_prot (void)
>> -{
>> - return (PROT_READ | PROT_WRITE
>> - | ((GL(dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
>> -}
>> -
>> static void *
>> allocate_thread_stack (size_t size, size_t guardsize)
>> {
>> /* MADV_ADVISE_GUARD does not require an additional PROT_NONE
>> mapping. */
>> - int prot = stack_prot ();
>> + int prot = GL(dl_stack_prot_flags);
>> if (atomic_load_relaxed (&allocate_stack_mode) ==
>> ALLOCATE_GUARD_PROT_NONE)
>> /* If a guard page is required, avoid committing memory by first
>> allocate
>> @@ -216,7 +210,7 @@ setup_stack_prot (char *mem, size_t size, struct
>> pthread *pd,
>> }
>> else
>> {
>> - const int prot = stack_prot ();
>> + const int prot = GL(dl_stack_prot_flags);
>> char *guardend = guard + guardsize;
>> #if _STACK_GROWS_DOWN
>> /* As defined at guard_position, for architectures with
>> downward stack
>> @@ -294,7 +288,7 @@ adjust_stack_prot (char *mem, size_t size, const
>> struct pthread *pd,
>> }
>> else if (pd->stack_mode == ALLOCATE_GUARD_PROT_NONE)
>> {
>> - const int prot = stack_prot ();
>> + const int prot = GL(dl_stack_prot_flags);
>> #if _STACK_GROWS_DOWN
>> return __mprotect (mem + guardsize, slacksize, prot) == 0;
>> #else
>> diff --git a/support/support_stack_alloc.c b/support/
>> support_stack_alloc.c
>> index 5e576bea74..132e7b4f70 100644
>> --- a/support/support_stack_alloc.c
>> +++ b/support/support_stack_alloc.c
>> @@ -64,11 +64,10 @@ support_stack_alloc (size_t size)
>> MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE|
>> MAP_STACK,
>> -1);
>> /* Some architecture still requires executable stack for the
>> signal return
>> - trampoline, although PF_X could be overridden if PT_GNU_STACK is
>> present.
>> - However since glibc does not export such information with a
>> proper ABI,
>> - it uses the historical permissions. */
>> - int prot = PROT_READ | PROT_WRITE
>> - | (DEFAULT_STACK_PERMS & PF_X ? PROT_EXEC : 0);
>> + trampoline, although PROT_EXEC could be overridden if
>> PT_GNU_STACK is
>> + present. However since glibc does not export such information
>> with a
>> + proper ABI, it uses the historical permissions. */
>> + int prot = DEFAULT_STACK_PROT_PERMS;
>> xmprotect (alloc_base + guardsize, stacksize, prot);
>> memset (alloc_base + guardsize, 0xA5, stacksize);
>> return (struct support_stack) { alloc_base + guardsize, stacksize,
>> guardsize };
>> diff --git a/sysdeps/alpha/stackinfo.h b/sysdeps/alpha/stackinfo.h
>> index a469964c10..d69647756b 100644
>> --- a/sysdeps/alpha/stackinfo.h
>> +++ b/sysdeps/alpha/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On Alpha the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/arm/stackinfo.h b/sysdeps/arm/stackinfo.h
>> index 3068352eab..30608f7062 100644
>> --- a/sysdeps/arm/stackinfo.h
>> +++ b/sysdeps/arm/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On Arm the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
>> index fc4a3de767..d92e28d6a9 100644
>> --- a/sysdeps/generic/ldsodefs.h
>> +++ b/sysdeps/generic/ldsodefs.h
>> @@ -419,6 +419,7 @@ struct rtld_global
>> /* Prevailing state of the stack, PF_X indicating it's
>> executable. */
>> EXTERN ElfW(Word) _dl_stack_flags;
>> + EXTERN int _dl_stack_prot_flags;
>> /* Flag signalling whether there are gaps in the module ID
>> allocation. */
>> EXTERN bool _dl_tls_dtv_gaps;
>> diff --git a/sysdeps/generic/stackinfo.h b/sysdeps/generic/stackinfo.h
>> index 8abbb3dff7..ab3e72e5c2 100644
>> --- a/sysdeps/generic/stackinfo.h
>> +++ b/sysdeps/generic/stackinfo.h
>> @@ -24,6 +24,6 @@
>> #include <elf.h>
>> #define _STACK_GROWS_DOWN 1
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W)
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE)
>> #endif
>> diff --git a/sysdeps/hppa/stackinfo.h b/sysdeps/hppa/stackinfo.h
>> index 53bb11fde0..22920d20a9 100644
>> --- a/sysdeps/hppa/stackinfo.h
>> +++ b/sysdeps/hppa/stackinfo.h
>> @@ -23,9 +23,9 @@
>> #include <elf.h>
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> /* On PA the stack grows up. */
>> #define _STACK_GROWS_UP 1
>> diff --git a/sysdeps/i386/stackinfo.h b/sysdeps/i386/stackinfo.h
>> index 74e82278d3..8d7a46c405 100644
>> --- a/sysdeps/i386/stackinfo.h
>> +++ b/sysdeps/i386/stackinfo.h
>> @@ -26,9 +26,9 @@
>> /* On x86 the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> /* Access to the stack pointer. The macros are used in alloca_account
>> for which they need to act as barriers as well, hence the additional
>> diff --git a/sysdeps/m68k/stackinfo.h b/sysdeps/m68k/stackinfo.h
>> index 7a757df147..77672c71c4 100644
>> --- a/sysdeps/m68k/stackinfo.h
>> +++ b/sysdeps/m68k/stackinfo.h
>> @@ -26,9 +26,9 @@
>> /* On m68k the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK
>> - is present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK is
>> + * present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> /* Access to the stack pointer. */
>> #define stackinfo_get_sp() \
>> diff --git a/sysdeps/mach/htl/pt-stack-alloc.c b/sysdeps/mach/htl/pt-
>> stack-alloc.c
>> index 3e196f8ca7..42762bc0ad 100644
>> --- a/sysdeps/mach/htl/pt-stack-alloc.c
>> +++ b/sysdeps/mach/htl/pt-stack-alloc.c
>> @@ -33,7 +33,7 @@ __pthread_stack_alloc (void **stackaddr, size_t
>> stacksize)
>> error_t err;
>> vm_prot_t prot = VM_PROT_READ | VM_PROT_WRITE;
>> - if (GL(dl_stack_flags) & PF_X)
>> + if (GL(dl_stack_prot_flags) & PROT_EXEC)
>> prot |= VM_PROT_EXECUTE;
>> err = __vm_map (__mach_task_self (), (vm_offset_t *) stackaddr,
>> diff --git a/sysdeps/mach/hurd/dl-execstack.c b/sysdeps/mach/hurd/dl-
>> execstack.c
>> index dc4719bd38..9e69169367 100644
>> --- a/sysdeps/mach/hurd/dl-execstack.c
>> +++ b/sysdeps/mach/hurd/dl-execstack.c
>> @@ -38,7 +38,7 @@ _dl_make_stack_executable (const void *stack_endp)
>> return errno;
>> /* Remember that we changed the permission. */
>> - GL(dl_stack_flags) |= PF_X;
>> + GL(dl_stack_prot_flags) |= PROT_EXEC;
>> return 0;
>> #else
>> diff --git a/sysdeps/microblaze/stackinfo.h b/sysdeps/microblaze/
>> stackinfo.h
>> index 8960bd3d25..51d40a7732 100644
>> --- a/sysdeps/microblaze/stackinfo.h
>> +++ b/sysdeps/microblaze/stackinfo.h
>> @@ -27,8 +27,8 @@
>> /* On MicroBlaze the stack grows down. */
>> # define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -# define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h. */
>> diff --git a/sysdeps/mips/stackinfo.h b/sysdeps/mips/stackinfo.h
>> index 6cce9386d6..107a8ea7c9 100644
>> --- a/sysdeps/mips/stackinfo.h
>> +++ b/sysdeps/mips/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On MIPS the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/or1k/stackinfo.h b/sysdeps/or1k/stackinfo.h
>> index 39cf5c2456..d93a795c51 100644
>> --- a/sysdeps/or1k/stackinfo.h
>> +++ b/sysdeps/or1k/stackinfo.h
>> @@ -27,8 +27,8 @@
>> /* On or1k the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R | PF_W | PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/powerpc/powerpc32/stackinfo.h b/sysdeps/powerpc/
>> powerpc32/stackinfo.h
>> index 31cba55805..50a3b367c6 100644
>> --- a/sysdeps/powerpc/powerpc32/stackinfo.h
>> +++ b/sysdeps/powerpc/powerpc32/stackinfo.h
>> @@ -26,7 +26,7 @@
>> /* On PPC the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* PF_X can be overridden if PT_GNU_STACK is present but is presumed
>> absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* PROT_EXEC can be overridden if PT_GNU_STACK is present but is
>> presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/s390/stackinfo.h b/sysdeps/s390/stackinfo.h
>> index 657ab3487f..9be764495a 100644
>> --- a/sysdeps/s390/stackinfo.h
>> +++ b/sysdeps/s390/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On s390 the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/sh/stackinfo.h b/sysdeps/sh/stackinfo.h
>> index 8f7bf163be..e502993d24 100644
>> --- a/sysdeps/sh/stackinfo.h
>> +++ b/sysdeps/sh/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On SH the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/sparc/stackinfo.h b/sysdeps/sparc/stackinfo.h
>> index 23a74ed7fe..a4a0eb15c9 100644
>> --- a/sysdeps/sparc/stackinfo.h
>> +++ b/sysdeps/sparc/stackinfo.h
>> @@ -26,8 +26,8 @@
>> /* On sparc the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> #endif /* stackinfo.h */
>> diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/
>> sysv/linux/dl-execstack.c
>> index 6db9601656..81edcc8567 100644
>> --- a/sysdeps/unix/sysv/linux/dl-execstack.c
>> +++ b/sysdeps/unix/sysv/linux/dl-execstack.c
>> @@ -36,7 +36,7 @@ _dl_make_stack_executable (const void *stack_endp)
>> return errno;
>> /* Remember that we changed the permission. */
>> - GL(dl_stack_flags) |= PF_X;
>> + GL(dl_stack_prot_flags) |= PROT_EXEC;
>> return 0;
>> }
>> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/
>> linux/spawni.c
>> index eca1a84254..bc8476ff11 100644
>> --- a/sysdeps/unix/sysv/linux/spawni.c
>> +++ b/sysdeps/unix/sysv/linux/spawni.c
>> @@ -348,9 +348,6 @@ __spawnix (int *pid, const char *file,
>> return errno;
>> }
>> - int prot = (PROT_READ | PROT_WRITE
>> - | ((GL (dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
>> -
>> /* Add a slack area for child's stack. */
>> size_t argv_size = (argc * sizeof (void *)) + 512;
>> /* We need at least a few pages in case the compiler's stack
>> checking is
>> @@ -361,7 +358,7 @@ __spawnix (int *pid, const char *file,
>> where it might use about 1k extra stack space). */
>> argv_size += (32 * 1024);
>> size_t stack_size = ALIGN_UP (argv_size, GLRO(dl_pagesize));
>> - void *stack = __mmap (NULL, stack_size, prot,
>> + void *stack = __mmap (NULL, stack_size, GL (dl_stack_prot_flags),
>> MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
>> if (__glibc_unlikely (stack == MAP_FAILED))
>> return errno;
>> diff --git a/sysdeps/x86_64/stackinfo.h b/sysdeps/x86_64/stackinfo.h
>> index 416d687869..0e88e6d94e 100644
>> --- a/sysdeps/x86_64/stackinfo.h
>> +++ b/sysdeps/x86_64/stackinfo.h
>> @@ -32,9 +32,9 @@
>> /* On x86_64 the stack grows down. */
>> #define _STACK_GROWS_DOWN 1
>> -/* Default to an executable stack. PF_X can be overridden if
>> PT_GNU_STACK is
>> - * present, but it is presumed absent. */
>> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
>> +/* Default to an executable stack. PROT_EXEC can be overridden if
>> PT_GNU_STACK
>> + * is present, but it is presumed absent. */
>> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>> /* Access to the stack pointer. The macros are used in alloca_account
>> for which they need to act as barriers as well, hence the additional
>
More information about the Libc-alpha
mailing list