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Date:	Fri, 26 Oct 2007 16:42:15 +0100
From:	David Howells <dhowells@...hat.com>
To:	torvalds@...l.org, akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, linux-am33-list@...hat.com,
	dhowells@...hat.com
Subject: [PATCH 1/2] MN10300: Permit AOUT library support to be suppressed in
	ELF binfmt

Permit AOUT library support to be suppressed in the ELF binfmt if the arch does
not support it.  AOUT support is suppressed by adding:

	config NO_AOUT_SUPPORT
		def_bool y

to the arch Kconfig file.

The MN10300 architecture does not support the AOUT binfmt, so the ELF binfmt
should not be permitted to go looking for AOUT libraries to load.

Signed-off-by: David Howells <dhowells@...hat.com>
---

 fs/Kconfig.binfmt     |    3 ++-
 fs/binfmt_elf.c       |   30 ++++++++++++++++++++++--------
 include/linux/a.out.h |    6 ++++++
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index d4fc609..a9ea391 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -57,7 +57,8 @@ config BINFMT_SHARED_FLAT
 
 config BINFMT_AOUT
 	tristate "Kernel support for a.out and ECOFF binaries"
-	depends on X86_32 || ALPHA || ARM || M68K || SPARC32
+	depends on (X86_32 || ALPHA || ARM || M68K || SPARC32) && \
+		!NO_AOUT_SUPPORT
 	---help---
 	  A.out (Assembler.OUTput) is a set of formats for libraries and
 	  executables used in the earliest versions of UNIX.  Linux used
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index ba8de7c..5a348c6 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -464,6 +464,7 @@ out:
 	return error;
 }
 
+#ifndef CONFIG_NO_AOUT_SUPPORT
 static unsigned long load_aout_interp(struct exec *interp_ex,
 		struct file *interpreter)
 {
@@ -509,6 +510,10 @@ static unsigned long load_aout_interp(struct exec *interp_ex,
 out:
 	return elf_entry;
 }
+#else
+extern unsigned long load_aout_interp(struct exec *interp_ex,
+				      struct file *interpreter);
+#endif
 
 /*
  * These are the functions used to load ELF style executables and shared
@@ -516,9 +521,15 @@ out:
  */
 
 #define INTERPRETER_NONE 0
-#define INTERPRETER_AOUT 1
 #define INTERPRETER_ELF 2
 
+#ifndef CONFIG_NO_AOUT_SUPPORT
+#define INTERPRETER_AOUT 1
+#define IS_AOUT_INTERP(x) ((x) == INTERPRETER_AOUT)
+#else
+#define IS_AOUT_INTERP(x) (0)
+#endif
+
 #ifndef STACK_RND_MASK
 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
 #endif
@@ -734,6 +745,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 	/* Some simple consistency checks for the interpreter */
 	if (elf_interpreter) {
 		static int warn;
+#ifndef CONFIG_NO_AOUT_SUPPORT
 		interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;
 
 		/* Now figure out which format our binary is */
@@ -741,11 +753,13 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 		    (N_MAGIC(loc->interp_ex) != ZMAGIC) &&
 		    (N_MAGIC(loc->interp_ex) != QMAGIC))
 			interpreter_type = INTERPRETER_ELF;
-
+#else
+		interpreter_type = INTERPRETER_ELF;
+#endif
 		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 			interpreter_type &= ~INTERPRETER_ELF;
 
-		if (interpreter_type == INTERPRETER_AOUT && warn < 10) {
+		if (IS_AOUT_INTERP(interpreter_type) && warn < 10) {
 			printk(KERN_WARNING "a.out ELF interpreter %s is "
 				"deprecated and will not be supported "
 				"after Linux 2.6.25\n", elf_interpreter);
@@ -774,7 +788,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 
 	/* OK, we are done with that, now set up the arg stuff,
 	   and then start this sucker up */
-	if ((!bprm->sh_bang) && (interpreter_type == INTERPRETER_AOUT)) {
+	if (IS_AOUT_INTERP(interpreter_type) && !bprm->sh_bang) {
 		char *passed_p = passed_fileno;
 		sprintf(passed_fileno, "%d", elf_exec_fileno);
 
@@ -961,7 +975,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 	}
 
 	if (elf_interpreter) {
-		if (interpreter_type == INTERPRETER_AOUT)
+		if (IS_AOUT_INTERP(interpreter_type))
 			elf_entry = load_aout_interp(&loc->interp_ex,
 						     interpreter);
 		else
@@ -990,7 +1004,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 
 	kfree(elf_phdata);
 
-	if (interpreter_type != INTERPRETER_AOUT)
+	if (!IS_AOUT_INTERP(interpreter_type))
 		sys_close(elf_exec_fileno);
 
 	set_binfmt(&elf_format);
@@ -1006,14 +1020,14 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 	compute_creds(bprm);
 	current->flags &= ~PF_FORKNOEXEC;
 	retval = create_elf_tables(bprm, &loc->elf_ex,
-			  (interpreter_type == INTERPRETER_AOUT),
+			  IS_AOUT_INTERP(interpreter_type),
 			  load_addr, interp_load_addr);
 	if (retval < 0) {
 		send_sig(SIGKILL, current, 0);
 		goto out;
 	}
 	/* N.B. passed_fileno might not be initialized? */
-	if (interpreter_type == INTERPRETER_AOUT)
+	if (IS_AOUT_INTERP(interpreter_type))
 		current->mm->arg_start += strlen(passed_fileno) + 1;
 	current->mm->end_code = end_code;
 	current->mm->start_code = start_code;
diff --git a/include/linux/a.out.h b/include/linux/a.out.h
index f913cc3..9624833 100644
--- a/include/linux/a.out.h
+++ b/include/linux/a.out.h
@@ -1,6 +1,8 @@
 #ifndef __A_OUT_GNU_H__
 #define __A_OUT_GNU_H__
 
+#ifndef CONFIG_NO_AOUT_SUPPORT
+
 #define __GNU_EXEC_MACROS__
 
 #ifndef __STRUCT_EXEC_OVERRIDE__
@@ -265,4 +267,8 @@ struct relocation_info
 #endif /* no N_RELOCATION_INFO_DECLARED.  */
 
 
+#else /* !CONFIG_NO_AOUT_SUPPORT */
+struct exec {
+};
+#endif /* !CONFIG_NO_AOUT_SUPPORT */
 #endif /* __A_OUT_GNU_H__ */

-
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