[7/8] Consolidate dl-osinfo.h into the generic implementation

Message ID 20260603000656.3287796-8-adhemerval.zanella@linaro.org (mailing list archive)
State Superseded
Delegated to: DJ Delorie
Headers
Series Pointer guard hardening and consolidation |

Checks

Context Check Description
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Commit Message

Adhemerval Zanella Netto June 3, 2026, 12:04 a.m. UTC
  The generic and the Linux _dl_setup_stack_chk_guard and
_dl_setup_pointer_guard are identical when the kernel provides the
AT_RANDOM auxiliary vector, which is always the case on the supported
Linux kernels; the generic version only adds a fallback for a missing
AT_RANDOM.  Remove the Linux-specific dl-osinfo.h and use the generic
one for all targets.

The removed header pulled in <dl-sysdep.h>, which is what transitively
declared __libc_enable_secure for dl-parse_auxv.h; include <unistd.h>
there directly so it no longer relies on that.  Include <string.h> in
the generic header so it is self-contained.
---
 sysdeps/generic/dl-osinfo.h             |  1 +
 sysdeps/unix/sysv/linux/dl-osinfo.h     | 54 -------------------------
 sysdeps/unix/sysv/linux/dl-parse_auxv.h |  1 +
 3 files changed, 2 insertions(+), 54 deletions(-)
 delete mode 100644 sysdeps/unix/sysv/linux/dl-osinfo.h
  

Comments

DJ Delorie June 10, 2026, 9:43 p.m. UTC | #1
LGTM
Reviewed-by: DJ Delorie <dj@redhat.com>
  

Patch

diff --git a/sysdeps/generic/dl-osinfo.h b/sysdeps/generic/dl-osinfo.h
index de46926abc9..5bb55cfe8a1 100644
--- a/sysdeps/generic/dl-osinfo.h
+++ b/sysdeps/generic/dl-osinfo.h
@@ -18,6 +18,7 @@ 
 
 #include <endian.h>
 #include <stdint.h>
+#include <string.h>
 
 static inline uintptr_t __attribute__ ((always_inline))
 _dl_setup_stack_chk_guard (void *dl_random)
diff --git a/sysdeps/unix/sysv/linux/dl-osinfo.h b/sysdeps/unix/sysv/linux/dl-osinfo.h
deleted file mode 100644
index 5ff92b76f96..00000000000
--- a/sysdeps/unix/sysv/linux/dl-osinfo.h
+++ /dev/null
@@ -1,54 +0,0 @@ 
-/* Operating system specific code for generic dynamic loader functions.  Linux.
-   Copyright (C) 2000-2026 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-sysdep.h>
-#include <endian.h>
-#include <fcntl.h>
-#include <stdint.h>
-#include <not-cancel.h>
-
-static inline uintptr_t __attribute__ ((always_inline))
-_dl_setup_stack_chk_guard (void *dl_random)
-{
-  union
-  {
-    uintptr_t num;
-    unsigned char bytes[sizeof (uintptr_t)];
-  } ret;
-
-  /* We need in the moment only 8 bytes on 32-bit platforms and 16
-     bytes on 64-bit platforms.  Therefore we can use the data
-     directly and not use the kernel-provided data to seed a PRNG.  */
-  memcpy (ret.bytes, dl_random, sizeof (ret));
-#if BYTE_ORDER == LITTLE_ENDIAN
-  ret.num &= ~(uintptr_t) 0xff;
-#elif BYTE_ORDER == BIG_ENDIAN
-  ret.num &= ~((uintptr_t) 0xff << (8 * (sizeof (ret) - 1)));
-#else
-# error "BYTE_ORDER unknown"
-#endif
-  return ret.num;
-}
-
-static inline uintptr_t __attribute__ ((always_inline))
-_dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard)
-{
-  uintptr_t ret;
-  memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret));
-  return ret;
-}
diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h
index 69b6905f7ce..d1cd4373239 100644
--- a/sysdeps/unix/sysv/linux/dl-parse_auxv.h
+++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h
@@ -22,6 +22,7 @@ 
 #include <ldsodefs.h>
 #include <link.h>
 #include <rseq-internal.h>
+#include <unistd.h>		/* For __libc_enable_secure.  */
 
 typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];