handle suicide on late failure exits in execve() in search_binary_handler()

... rather than doing that in the guts of ->load_binary().
[updated to fix the bug spotted by Shentino - for SIGSEGV we really need
something stronger than send_sig_info(); again, better do that in one place]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/x86/ia32/ia32_aout.c

@@ -308,11 +308,8 @@ static int load_aout_binary(struct linux_binprm *bprm)
 		(current->mm->start_brk = N_BSSADDR(ex));
 
 	retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
-	if (retval < 0) {
-		/* Someone check-me: is this error path enough? */
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		return retval;
-	}
 
 	install_exec_creds(bprm);
 
@@ -324,17 +321,13 @@ static int load_aout_binary(struct linux_binprm *bprm)
 
 		error = vm_brk(text_addr & PAGE_MASK, map_size);
 
-		if (error != (text_addr & PAGE_MASK)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != (text_addr & PAGE_MASK))
 			return error;
-		}
 
 		error = read_code(bprm->file, text_addr, 32,
 				  ex.a_text + ex.a_data);
-		if ((signed long)error < 0) {
-			send_sig(SIGKILL, current, 0);
+		if ((signed long)error < 0)
 			return error;
-		}
 	} else {
 #ifdef WARN_OLD
 		static unsigned long error_time, error_time2;
@@ -368,20 +361,16 @@ static int load_aout_binary(struct linux_binprm *bprm)
 				MAP_EXECUTABLE | MAP_32BIT,
 				fd_offset);
 
-		if (error != N_TXTADDR(ex)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != N_TXTADDR(ex))
 			return error;
-		}
 
 		error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 				PROT_READ | PROT_WRITE | PROT_EXEC,
 				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 				MAP_EXECUTABLE | MAP_32BIT,
 				fd_offset + ex.a_text);
-		if (error != N_DATADDR(ex)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != N_DATADDR(ex))
 			return error;
-		}
 	}
 beyond_if:
 	set_binfmt(&aout_format);

fs/binfmt_aout.c

@@ -256,11 +256,8 @@ static int load_aout_binary(struct linux_binprm * bprm)
 		(current->mm->start_brk = N_BSSADDR(ex));
 
 	retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
-	if (retval < 0) {
-		/* Someone check-me: is this error path enough? */
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		return retval;
-	}
 
 	install_exec_creds(bprm);
 
@@ -278,17 +275,13 @@ static int load_aout_binary(struct linux_binprm * bprm)
 		map_size = ex.a_text+ex.a_data;
 #endif
 		error = vm_brk(text_addr & PAGE_MASK, map_size);
-		if (error != (text_addr & PAGE_MASK)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != (text_addr & PAGE_MASK))
 			return error;
-		}
 
 		error = read_code(bprm->file, text_addr, pos,
 				  ex.a_text+ex.a_data);
-		if ((signed long)error < 0) {
-			send_sig(SIGKILL, current, 0);
+		if ((signed long)error < 0)
 			return error;
-		}
 	} else {
 		if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 		    (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
@@ -315,28 +308,22 @@ static int load_aout_binary(struct linux_binprm * bprm)
 			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 			fd_offset);
 
-		if (error != N_TXTADDR(ex)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != N_TXTADDR(ex))
 			return error;
-		}
 
 		error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 				PROT_READ | PROT_WRITE | PROT_EXEC,
 				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 				fd_offset + ex.a_text);
-		if (error != N_DATADDR(ex)) {
-			send_sig(SIGKILL, current, 0);
+		if (error != N_DATADDR(ex))
 			return error;
-		}
 	}
 beyond_if:
 	set_binfmt(&aout_format);
 
 	retval = set_brk(current->mm->start_brk, current->mm->brk);
-	if (retval < 0) {
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		return retval;
-	}
 
 	current->mm->start_stack =
 		(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);

fs/binfmt_elf.c

@@ -738,10 +738,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	   change some of these later */
 	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
 				 executable_stack);
-	if (retval < 0) {
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		goto out_free_dentry;
-	}
 	
 	current->mm->start_stack = bprm->p;
 
@@ -763,10 +761,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			   and clear the area.  */
 			retval = set_brk(elf_bss + load_bias,
 					 elf_brk + load_bias);
-			if (retval) {
-				send_sig(SIGKILL, current, 0);
+			if (retval)
 				goto out_free_dentry;
-			}
 			nbyte = ELF_PAGEOFFSET(elf_bss);
 			if (nbyte) {
 				nbyte = ELF_MIN_ALIGN - nbyte;
@@ -820,7 +816,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
 				elf_prot, elf_flags, 0);
 		if (BAD_ADDR(error)) {
-			send_sig(SIGKILL, current, 0);
 			retval = IS_ERR((void *)error) ?
 				PTR_ERR((void*)error) : -EINVAL;
 			goto out_free_dentry;
@@ -851,7 +846,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		    elf_ppnt->p_memsz > TASK_SIZE ||
 		    TASK_SIZE - elf_ppnt->p_memsz < k) {
 			/* set_brk can never work. Avoid overflows. */
-			send_sig(SIGKILL, current, 0);
 			retval = -EINVAL;
 			goto out_free_dentry;
 		}
@@ -883,12 +877,9 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	 * up getting placed where the bss needs to go.
 	 */
 	retval = set_brk(elf_bss, elf_brk);
-	if (retval) {
-		send_sig(SIGKILL, current, 0);
+	if (retval)
 		goto out_free_dentry;
-	}
 	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
-		send_sig(SIGSEGV, current, 0);
 		retval = -EFAULT; /* Nobody gets to see this, but.. */
 		goto out_free_dentry;
 	}
@@ -909,7 +900,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			elf_entry += loc->interp_elf_ex.e_entry;
 		}
 		if (BAD_ADDR(elf_entry)) {
-			force_sig(SIGSEGV, current);
 			retval = IS_ERR((void *)elf_entry) ?
 					(int)elf_entry : -EINVAL;
 			goto out_free_dentry;
@@ -922,7 +912,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	} else {
 		elf_entry = loc->elf_ex.e_entry;
 		if (BAD_ADDR(elf_entry)) {
-			force_sig(SIGSEGV, current);
 			retval = -EINVAL;
 			goto out_free_dentry;
 		}
@@ -934,19 +923,15 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
-	if (retval < 0) {
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		goto out;
-	}
 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 
 	install_exec_creds(bprm);
 	retval = create_elf_tables(bprm, &loc->elf_ex,
 			  load_addr, interp_load_addr);
-	if (retval < 0) {
-		send_sig(SIGKILL, current, 0);
+	if (retval < 0)
 		goto out;
-	}
 	/* N.B. passed_fileno might not be initialized? */
 	current->mm->end_code = end_code;
 	current->mm->start_code = start_code;

fs/binfmt_elf_fdpic.c

@@ -317,8 +317,8 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 		goto error;
 
 	/* there's now no turning back... the old userspace image is dead,
-	 * defunct, deceased, etc. after this point we have to exit via
-	 * error_kill */
+	 * defunct, deceased, etc.
+	 */
 	set_personality(PER_LINUX_FDPIC);
 	if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
 		current->personality |= READ_IMPLIES_EXEC;
@@ -343,24 +343,22 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 
 	retval = setup_arg_pages(bprm, current->mm->start_stack,
 				 executable_stack);
-	if (retval < 0) {
-		send_sig(SIGKILL, current, 0);
-		goto error_kill;
-	}
+	if (retval < 0)
+		goto error;
 #endif
 
 	/* load the executable and interpreter into memory */
 	retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
 				    "executable");
 	if (retval < 0)
-		goto error_kill;
+		goto error;
 
 	if (interpreter_name) {
 		retval = elf_fdpic_map_file(&interp_params, interpreter,
 					    current->mm, "interpreter");
 		if (retval < 0) {
 			printk(KERN_ERR "Unable to load interpreter\n");
-			goto error_kill;
+			goto error;
 		}
 
 		allow_write_access(interpreter);
@@ -397,7 +395,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 	if (IS_ERR_VALUE(current->mm->start_brk)) {
 		retval = current->mm->start_brk;
 		current->mm->start_brk = 0;
-		goto error_kill;
+		goto error;
 	}
 
 	current->mm->brk = current->mm->start_brk;
@@ -410,7 +408,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 	install_exec_creds(bprm);
 	if (create_elf_fdpic_tables(bprm, current->mm,
 				    &exec_params, &interp_params) < 0)
-		goto error_kill;
+		goto error;
 
 	kdebug("- start_code  %lx", current->mm->start_code);
 	kdebug("- end_code    %lx", current->mm->end_code);
@@ -449,12 +447,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 	kfree(interp_params.phdrs);
 	kfree(interp_params.loadmap);
 	return retval;
-
-	/* unrecoverable error - kill the process */
-error_kill:
-	send_sig(SIGSEGV, current, 0);
-	goto error;
-
 }
 
 /*****************************************************************************/

fs/exec.c

@@ -1372,18 +1372,23 @@ int search_binary_handler(struct linux_binprm *bprm)
 		read_unlock(&binfmt_lock);
 		bprm->recursion_depth++;
 		retval = fmt->load_binary(bprm);
+		read_lock(&binfmt_lock);
+		put_binfmt(fmt);
 		bprm->recursion_depth--;
-		if (retval >= 0 || retval != -ENOEXEC ||
-		    bprm->mm == NULL || bprm->file == NULL) {
-			put_binfmt(fmt);
+		if (retval < 0 && !bprm->mm) {
+			/* we got to flush_old_exec() and failed after it */
+			read_unlock(&binfmt_lock);
+			force_sigsegv(SIGSEGV, current);
+			return retval;
+		}
+		if (retval != -ENOEXEC || !bprm->file) {
+			read_unlock(&binfmt_lock);
 			return retval;
 		}
-		read_lock(&binfmt_lock);
-		put_binfmt(fmt);
 	}
 	read_unlock(&binfmt_lock);
 
-	if (need_retry && retval == -ENOEXEC) {
+	if (need_retry) {
 		if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
 		    printable(bprm->buf[2]) && printable(bprm->buf[3]))
 			return retval;