From 221af7f87b97431e3ee21ce4b0e77d5411cf1549 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 28 Jan 2010 22:14:42 -0800 Subject: Split 'flush_old_exec' into two functions 'flush_old_exec()' is the point of no return when doing an execve(), and it is pretty badly misnamed. It doesn't just flush the old executable environment, it also starts up the new one. Which is very inconvenient for things like setting up the new personality, because we want the new personality to affect the starting of the new environment, but at the same time we do _not_ want the new personality to take effect if flushing the old one fails. As a result, the x86-64 '32-bit' personality is actually done using this insane "I'm going to change the ABI, but I haven't done it yet" bit (TIF_ABI_PENDING), with SET_PERSONALITY() not actually setting the personality, but just the "pending" bit, so that "flush_thread()" can do the actual personality magic. This patch in no way changes any of that insanity, but it does split the 'flush_old_exec()' function up into a preparatory part that can fail (still called flush_old_exec()), and a new part that will actually set up the new exec environment (setup_new_exec()). All callers are changed to trivially comply with the new world order. Signed-off-by: H. Peter Anvin Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 27 ++------------------------- 1 file changed, 2 insertions(+), 25 deletions(-) (limited to 'fs/binfmt_elf.c') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index edd90c49003c..fd5b2ea5d299 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -662,27 +662,6 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0') goto out_free_interp; - /* - * The early SET_PERSONALITY here is so that the lookup - * for the interpreter happens in the namespace of the - * to-be-execed image. SET_PERSONALITY can select an - * alternate root. - * - * However, SET_PERSONALITY is NOT allowed to switch - * this task into the new images's memory mapping - * policy - that is, TASK_SIZE must still evaluate to - * that which is appropriate to the execing application. - * This is because exit_mmap() needs to have TASK_SIZE - * evaluate to the size of the old image. - * - * So if (say) a 64-bit application is execing a 32-bit - * application it is the architecture's responsibility - * to defer changing the value of TASK_SIZE until the - * switch really is going to happen - do this in - * flush_thread(). - akpm - */ - SET_PERSONALITY(loc->elf_ex); - interpreter = open_exec(elf_interpreter); retval = PTR_ERR(interpreter); if (IS_ERR(interpreter)) @@ -730,9 +709,6 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) /* Verify the interpreter has a valid arch */ if (!elf_check_arch(&loc->interp_elf_ex)) goto out_free_dentry; - } else { - /* Executables without an interpreter also need a personality */ - SET_PERSONALITY(loc->elf_ex); } /* Flush all traces of the currently running executable */ @@ -752,7 +728,8 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) current->flags |= PF_RANDOMIZE; - arch_pick_mmap_layout(current->mm); + + setup_new_exec(bprm); /* Do this so that we can load the interpreter, if need be. We will change some of these later */ -- cgit v1.2.3