[PATCH 0/3] binfmt_elf_fdpic: auxvec updates, v2.

[PATCH 0/3] binfmt_elf_fdpic: auxvec updates, v2.

[Paul Mundt]

This is a tiny series of patches for bringing binfmt_elf_fdpic back in
line with binfmt_elf in terms of auxiliary vector layout, particularly
for the new entries that have popped up recently.

[PATCH 1/3] binfmt_elf_fdpic: Support auxvec base platform string.
[PATCH 2/3] binfmt_elf_fdpic: Convert initial stack alignment to arch_align_stack().
[PATCH 3/3] binfmt_elf_fdpic: Wire up AT_EXECFD, AT_EXECFN, AT_SECURE.

Changes since the last version include the updated 2/3 patch and a
cosmetic fixup in 1/3.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 fs/binfmt_elf_fdpic.c |   89 +++++++++++++++++++++++++++++++++++---------------
 1 file changed, 64 insertions(+), 25 deletions(-)

[PATCH 1/3] binfmt_elf_fdpic: Support auxvec base platform string.

[Paul Mundt]

Commit 483fad1c3fa1060d7e6710e84a065ad514571739 introduces
AT_BASE_PLATFORM, but only implements it for binfmt_elf. Given that
AT_VECTOR_SIZE_BASE is unconditionally enlarged for us, and it's only
optionally added in for the platforms that set ELF_BASE_PLATFORM, wire
it up for binfmt_elf_fdpic, too.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 fs/binfmt_elf_fdpic.c |   50 ++++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 80c1f95..0955d03 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -455,6 +455,16 @@ error_kill:
 }
 
 /*****************************************************************************/
+
+#ifndef ELF_BASE_PLATFORM
+/*
+ * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
+ * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
+ * will be copied to the user stack in the same manner as AT_PLATFORM.
+ */
+#define ELF_BASE_PLATFORM NULL
+#endif
+
 /*
  * present useful information to the program
  */
@@ -466,8 +476,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	unsigned long sp, csp, nitems;
 	elf_caddr_t __user *argv, *envp;
 	size_t platform_len = 0, len;
-	char *k_platform;
-	char __user *u_platform, *p;
+	char *k_platform, *k_base_platform;
+	char __user *u_platform, *u_base_platform, *p;
 	long hwcap;
 	int loop;
 	int nr;	/* reset for each csp adjustment */
@@ -483,11 +493,14 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 		return -EFAULT;
 #endif
 
-	/* get hold of platform and hardware capabilities masks for the machine
-	 * we are running on.  In some cases (Sparc), this info is impossible
-	 * to get, in others (i386) it is merely difficult.
-	 */
 	hwcap = ELF_HWCAP;
+
+	/*
+	 * If this architecture has a platform capability string, copy it
+	 * to userspace.  In some cases (Sparc), this info is impossible
+	 * for userspace to get any other way, in others (i386) it is
+	 * merely difficult.
+	 */
 	k_platform = ELF_PLATFORM;
 	u_platform = NULL;
 
@@ -499,6 +512,21 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 			return -EFAULT;
 	}
 
+	/*
+	 * If this architecture has a "base" platform capability
+	 * string, copy it to userspace.
+	 */
+	k_base_platform = ELF_BASE_PLATFORM;
+	u_base_platform = NULL;
+
+	if (k_base_platform) {
+		platform_len = strlen(k_base_platform) + 1;
+		sp -= platform_len;
+		u_base_platform = (char __user *) sp;
+		if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
+			return -EFAULT;
+	}
+
 #if defined(__i386__) && defined(CONFIG_SMP)
 	/* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 	 * by the processes running on the same package. One thing we can do is
@@ -543,7 +571,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	/* force 16 byte _final_ alignment here for generality */
 #define DLINFO_ITEMS 13
 
-	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
+	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
+		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 
 	csp = sp;
 	sp -= nitems * 2 * sizeof(unsigned long);
@@ -575,6 +604,13 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 			    (elf_addr_t) (unsigned long) u_platform);
 	}
 
+	if (k_base_platform) {
+		nr = 0;
+		csp -= 2 * sizeof(unsigned long);
+		NEW_AUX_ENT(AT_BASE_PLATFORM,
+			    (elf_addr_t) (unsigned long) u_base_platform);
+	}
+
 	nr = 0;
 	csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 	NEW_AUX_ENT(AT_HWCAP,	hwcap);

[PATCH 2/3] binfmt_elf_fdpic: Convert initial stack alignment to arch_align_stack()

[Paul Mundt]

binfmt_elf_fdpic seems to have grabbed a hard-coded hack from an ancient
version of binfmt_elf in order to try and fix up initial stack alignment
on multi-threaded x86, which while in addition to being unused, was also
pushed down beyond the first set of operations on the stack pointer,
negating the entire purpose.

These days, we have an architecture independent arch_align_stack(), so we
switch to using that instead. Move the initial alignment up before the
initial stores while we're at it.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/binfmt_elf_fdpic.c |   25 ++++++++-----------------
 1 files changed, 8 insertions(+), 17 deletions(-)


diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 7c83605..f9d6eaa 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -466,7 +466,8 @@ error_kill:
 #endif
 
 /*
- * present useful information to the program
+ * present useful information to the program by shovelling it onto the new
+ * process's stack
  */
 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 				   struct mm_struct *mm,
@@ -482,9 +483,13 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	int loop;
 	int nr;	/* reset for each csp adjustment */
 
-	/* we're going to shovel a whole load of stuff onto the stack */
 #ifdef CONFIG_MMU
-	sp = bprm->p;
+	/* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
+	 * by the processes running on the same package. One thing we can do is
+	 * to shuffle the initial stack for them, so we give the architecture
+	 * an opportunity to do so here.
+	 */
+	sp = arch_align_stack(bprm->p);
 #else
 	sp = mm->start_stack;
 
@@ -527,20 +532,6 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 			return -EFAULT;
 	}
 
-#if defined(__i386__) && defined(CONFIG_SMP)
-	/* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
-	 * by the processes running on the same package. One thing we can do is
-	 * to shuffle the initial stack for them.
-	 *
-	 * the conditionals here are unneeded, but kept in to make the code
-	 * behaviour the same as pre change unless we have hyperthreaded
-	 * processors. This keeps Mr Marcelo Person happier but should be
-	 * removed for 2.5
-	 */
-	if (smp_num_siblings > 1)
-		sp = sp - ((current->pid % 64) << 7);
-#endif
-
 	sp &= ~7UL;
 
 	/* stack the load map(s) */

[PATCH 3/3] binfmt_elf_fdpic: Wire up AT_EXECFD, AT_EXECFN, AT_SECURE.

[Paul Mundt]

These auxvec entries are the only ones left unhandled out of the current
base implementation. This syncs up binfmt_elf_fdpic with linux/auxvec.h
and current binfmt_elf.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Howells <dhowells@redhat.com>

---

 fs/binfmt_elf_fdpic.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index bc64f5f..f0dd83c 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -25,6 +25,7 @@
 #include <linux/fcntl.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/security.h>
 #include <linux/highmem.h>
 #include <linux/highuid.h>
 #include <linux/personality.h>
@@ -562,11 +563,14 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	}
 
 	/* force 16 byte _final_ alignment here for generality */
-#define DLINFO_ITEMS 13
+#define DLINFO_ITEMS 15
 
 	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) + \
 		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 
+	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
+		nitems++;
+
 	csp = sp;
 	sp -= nitems * 2 * sizeof(unsigned long);
 	sp -= (bprm->envc + 1) * sizeof(char *);	/* envv[] */
@@ -604,6 +608,12 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 			    (elf_addr_t) (unsigned long) u_base_platform);
 	}
 
+	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
+		nr = 0;
+		csp -= 2 * sizeof(unsigned long);
+		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
+	}
+
 	nr = 0;
 	csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 	NEW_AUX_ENT(AT_HWCAP,	hwcap);
@@ -619,6 +629,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) current->euid);
 	NEW_AUX_ENT(AT_GID,	(elf_addr_t) current->gid);
 	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) current->egid);
+	NEW_AUX_ENT(AT_SECURE,	security_bprm_secureexec(bprm));
+	NEW_AUX_ENT(AT_EXECFN,	bprm->exec);
 
 #ifdef ARCH_DLINFO
 	nr = 0;

Re: [PATCH 3/3] binfmt_elf_fdpic: Wire up AT_EXECFD, AT_EXECFN, AT_SECURE.

[Andrew Morton]

On Wed, 6 Aug 2008 19:36:15 +0900
Paul Mundt <lethal@linux-sh.org> wrote:

> These auxvec entries are the only ones left unhandled out of the current
> base implementation. This syncs up binfmt_elf_fdpic with linux/auxvec.h
> and current binfmt_elf.

The patches ran afoul of the credentials changes in linux-next.

#1 and #2 applied OK, but #3 tossed the below reject.  Please check
that my (fairly obvious) fixups are OK.

***************
*** 562,572 ****
  	}
  
  	/* force 16 byte _final_ alignment here for generality */
- #define DLINFO_ITEMS 13
  
  	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) + \
  		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
  
  	csp = sp;
  	sp -= nitems * 2 * sizeof(unsigned long);
  	sp -= (bprm->envc + 1) * sizeof(char *);	/* envv[] */
--- 563,576 ----
  	}
  
  	/* force 16 byte _final_ alignment here for generality */
+ #define DLINFO_ITEMS 15
  
  	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) + \
  		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
  
+ 	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
+ 		nitems++;
+ 
  	csp = sp;
  	sp -= nitems * 2 * sizeof(unsigned long);
  	sp -= (bprm->envc + 1) * sizeof(char *);	/* envv[] */
***************
*** 618,623 ****
  	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) current->euid);
  	NEW_AUX_ENT(AT_GID,	(elf_addr_t) current->gid);
  	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) current->egid);
  
  #ifdef ARCH_DLINFO
  	nr = 0;
--- 628,635 ----
  	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) current->euid);
  	NEW_AUX_ENT(AT_GID,	(elf_addr_t) current->gid);
  	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) current->egid);
+ 	NEW_AUX_ENT(AT_SECURE,	security_bprm_secureexec(bprm));
+ 	NEW_AUX_ENT(AT_EXECFN,	bprm->exec);
  
  #ifdef ARCH_DLINFO
  	nr = 0;

Re: [PATCH 3/3] binfmt_elf_fdpic: Wire up AT_EXECFD, AT_EXECFN, AT_SECURE.

[Paul Mundt]

On Mon, Aug 11, 2008 at 02:18:55PM -0700, Andrew Morton wrote:
> On Wed, 6 Aug 2008 19:36:15 +0900
> Paul Mundt <lethal@linux-sh.org> wrote:
> 
> > These auxvec entries are the only ones left unhandled out of the current
> > base implementation. This syncs up binfmt_elf_fdpic with linux/auxvec.h
> > and current binfmt_elf.
> 
> The patches ran afoul of the credentials changes in linux-next.
> 
> #1 and #2 applied OK, but #3 tossed the below reject.  Please check
> that my (fairly obvious) fixups are OK.
> 
Yes, your fixups look fine, thanks.

Also note that you are missing David's signed-off-by on 2/3:

http://marc.info/?l=linux-sh&m=121784461423443&w=2