Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753858Ab0BDRcf (ORCPT ); Thu, 4 Feb 2010 12:32:35 -0500 Received: from kroah.org ([198.145.64.141]:34715 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933198Ab0BDRVw (ORCPT ); Thu, 4 Feb 2010 12:21:52 -0500 X-Mailbox-Line: From linux@linux.site Thu Feb 4 09:15:05 2010 Message-Id: <20100204171505.353374675@linux.site> User-Agent: quilt/0.47-14.9 Date: Thu, 04 Feb 2010 09:12:01 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "H. Peter Anvin" , Greg Kroah-Hartman Subject: [30/74] Split flush_old_exec into two functions In-Reply-To: <20100204171850.GA16539@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8303 Lines: 251 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Linus Torvalds commit 221af7f87b97431e3ee21ce4b0e77d5411cf1549 upstream. '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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/sh/kernel/process_64.c | 2 +- arch/x86/ia32/ia32_aout.c | 10 ++++++---- fs/binfmt_aout.c | 1 + fs/binfmt_elf.c | 27 ++------------------------- fs/binfmt_elf_fdpic.c | 3 +++ fs/binfmt_flat.c | 1 + fs/binfmt_som.c | 1 + fs/exec.c | 26 ++++++++++++++++---------- include/linux/binfmts.h | 1 + include/linux/sched.h | 2 +- 10 files changed, 33 insertions(+), 41 deletions(-) --- a/arch/sh/kernel/process_64.c +++ b/arch/sh/kernel/process_64.c @@ -367,7 +367,7 @@ void exit_thread(void) void flush_thread(void) { - /* Called by fs/exec.c (flush_old_exec) to remove traces of a + /* Called by fs/exec.c (setup_new_exec) to remove traces of a * previously running executable. */ #ifdef CONFIG_SH_FPU if (last_task_used_math == current) { --- a/arch/x86/ia32/ia32_aout.c +++ b/arch/x86/ia32/ia32_aout.c @@ -308,15 +308,17 @@ static int load_aout_binary(struct linux if (retval) return retval; - regs->cs = __USER32_CS; - regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = - regs->r13 = regs->r14 = regs->r15 = 0; - /* OK, This is the point of no return */ set_personality(PER_LINUX); set_thread_flag(TIF_IA32); clear_thread_flag(TIF_ABI_PENDING); + setup_new_exec(bprm); + + regs->cs = __USER32_CS; + regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = + regs->r13 = regs->r14 = regs->r15 = 0; + current->mm->end_code = ex.a_text + (current->mm->start_code = N_TXTADDR(ex)); current->mm->end_data = ex.a_data + --- a/fs/binfmt_aout.c +++ b/fs/binfmt_aout.c @@ -263,6 +263,7 @@ static int load_aout_binary(struct linux #else set_personality(PER_LINUX); #endif + setup_new_exec(bprm); current->mm->end_code = ex.a_text + (current->mm->start_code = N_TXTADDR(ex)); --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -662,27 +662,6 @@ static int load_elf_binary(struct linux_ 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_ /* 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_ 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 */ --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -321,6 +321,9 @@ static int load_elf_fdpic_binary(struct set_personality(PER_LINUX_FDPIC); if (elf_read_implies_exec(&exec_params.hdr, executable_stack)) current->personality |= READ_IMPLIES_EXEC; + + setup_new_exec(bprm); + set_binfmt(&elf_fdpic_format); current->mm->start_code = 0; --- a/fs/binfmt_flat.c +++ b/fs/binfmt_flat.c @@ -519,6 +519,7 @@ static int load_flat_file(struct linux_b /* OK, This is the point of no return */ set_personality(PER_LINUX_32BIT); + setup_new_exec(bprm); } /* --- a/fs/binfmt_som.c +++ b/fs/binfmt_som.c @@ -227,6 +227,7 @@ load_som_binary(struct linux_binprm * bp /* OK, This is the point of no return */ current->flags &= ~PF_FORKNOEXEC; current->personality = PER_HPUX; + setup_new_exec(bprm); /* Set the task size for HP-UX processes such that * the gateway page is outside the address space. --- a/fs/exec.c +++ b/fs/exec.c @@ -931,9 +931,7 @@ void set_task_comm(struct task_struct *t int flush_old_exec(struct linux_binprm * bprm) { - char * name; - int i, ch, retval; - char tcomm[sizeof(current->comm)]; + int retval; /* * Make sure we have a private signal table and that @@ -953,6 +951,20 @@ int flush_old_exec(struct linux_binprm * goto out; bprm->mm = NULL; /* We're using it now */ + return 0; + +out: + return retval; +} +EXPORT_SYMBOL(flush_old_exec); + +void setup_new_exec(struct linux_binprm * bprm) +{ + int i, ch; + char * name; + char tcomm[sizeof(current->comm)]; + + arch_pick_mmap_layout(current->mm); /* This is the point of no return */ current->sas_ss_sp = current->sas_ss_size = 0; @@ -1009,14 +1021,8 @@ int flush_old_exec(struct linux_binprm * flush_signal_handlers(current, 0); flush_old_files(current->files); - - return 0; - -out: - return retval; } - -EXPORT_SYMBOL(flush_old_exec); +EXPORT_SYMBOL(setup_new_exec); /* * Prepare credentials and lock ->cred_guard_mutex. --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -101,6 +101,7 @@ extern int prepare_binprm(struct linux_b extern int __must_check remove_arg_zero(struct linux_binprm *); extern int search_binary_handler(struct linux_binprm *,struct pt_regs *); extern int flush_old_exec(struct linux_binprm * bprm); +extern void setup_new_exec(struct linux_binprm * bprm); extern int suid_dumpable; #define SUID_DUMP_DISABLE 0 /* No setuid dumping */ --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1354,7 +1354,7 @@ struct task_struct { char comm[TASK_COMM_LEN]; /* executable name excluding path - access with [gs]et_task_comm (which lock it with task_lock()) - - initialized normally by flush_old_exec */ + - initialized normally by setup_new_exec */ /* file system info */ int link_count, total_link_count; #ifdef CONFIG_SYSVIPC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/