1 files changed, 149 insertions, 64 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 6df42624e454..9ff89cb9657a 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -36,6 +36,8 @@
 #include <linux/personality.h>
 #include <linux/ptrace.h>
 #include <linux/fs_struct.h>
+#include <linux/file.h>
+#include <linux/mount.h>
 #include <linux/gfp.h>
 #include <linux/syscore_ops.h>
 #include <linux/version.h>
@@ -1378,8 +1380,8 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
                 memcpy(u->nodename, tmp, len);
                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
                 errno = 0;
+                uts_proc_notify(UTS_PROC_HOSTNAME);
         }
-        uts_proc_notify(UTS_PROC_HOSTNAME);
         up_write(&uts_sem);
         return errno;
 }
@@ -1429,8 +1431,8 @@ SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
                 memcpy(u->domainname, tmp, len);
                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
                 errno = 0;
+                uts_proc_notify(UTS_PROC_DOMAINNAME);
         }
-        uts_proc_notify(UTS_PROC_DOMAINNAME);
         up_write(&uts_sem);
         return errno;
 }
@@ -1784,77 +1786,102 @@ SYSCALL_DEFINE1(umask, int, mask)
 }
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
+static bool vma_flags_mismatch(struct vm_area_struct *vma,
+                               unsigned long required,
+                               unsigned long banned)
+{
+        return (vma->vm_flags & required) != required ||
+                (vma->vm_flags & banned);
+}
+
+static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
+{
+        struct file *exe_file;
+        struct dentry *dentry;
+        int err;
+
+        /*
+         * Setting new mm::exe_file is only allowed when no VM_EXECUTABLE vma's
+         * remain. So perform a quick test first.
+         */
+        if (mm->num_exe_file_vmas)
+                return -EBUSY;
+
+        exe_file = fget(fd);
+        if (!exe_file)
+                return -EBADF;
+
+        dentry = exe_file->f_path.dentry;
+
+        /*
+         * Because the original mm->exe_file points to executable file, make
+         * sure that this one is executable as well, to avoid breaking an
+         * overall picture.
+         */
+        err = -EACCES;
+        if (!S_ISREG(dentry->d_inode->i_mode)   ||
+            exe_file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+                goto exit;
+
+        err = inode_permission(dentry->d_inode, MAY_EXEC);
+        if (err)
+                goto exit;
+
+        /*
+         * The symlink can be changed only once, just to disallow arbitrary
+         * transitions malicious software might bring in. This means one
+         * could make a snapshot over all processes running and monitor
+         * /proc/pid/exe changes to notice unusual activity if needed.
+         */
+        down_write(&mm->mmap_sem);
+        if (likely(!mm->exe_file))
+                set_mm_exe_file(mm, exe_file);
+        else
+                err = -EBUSY;
+        up_write(&mm->mmap_sem);
+
+exit:
+        fput(exe_file);
+        return err;
+}
+
 static int prctl_set_mm(int opt, unsigned long addr,
                         unsigned long arg4, unsigned long arg5)
 {
         unsigned long rlim = rlimit(RLIMIT_DATA);
-        unsigned long vm_req_flags;
-        unsigned long vm_bad_flags;
-        struct vm_area_struct *vma;
-        int error = 0;
         struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        int error;
 
-        if (arg4 | arg5)
+        if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
                 return -EINVAL;
 
         if (!capable(CAP_SYS_RESOURCE))
                 return -EPERM;
 
+        if (opt == PR_SET_MM_EXE_FILE)
+                return prctl_set_mm_exe_file(mm, (unsigned int)addr);
+
         if (addr >= TASK_SIZE)
                 return -EINVAL;
 
+        error = -EINVAL;
+
         down_read(&mm->mmap_sem);
         vma = find_vma(mm, addr);
 
-        if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) {
-                /* It must be existing VMA */
-                if (!vma || vma->vm_start > addr)
-                        goto out;
-        }
-
-        error = -EINVAL;
         switch (opt) {
         case PR_SET_MM_START_CODE:
+                mm->start_code = addr;
+                break;
         case PR_SET_MM_END_CODE:
-                vm_req_flags = VM_READ | VM_EXEC;
-                vm_bad_flags = VM_WRITE | VM_MAYSHARE;
-
-                if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
-                    (vma->vm_flags & vm_bad_flags))
-                        goto out;
-
-                if (opt == PR_SET_MM_START_CODE)
-                        mm->start_code = addr;
-                else
-                        mm->end_code = addr;
+                mm->end_code = addr;
                 break;
-
         case PR_SET_MM_START_DATA:
-        case PR_SET_MM_END_DATA:
-                vm_req_flags = VM_READ | VM_WRITE;
-                vm_bad_flags = VM_EXEC | VM_MAYSHARE;
-
-                if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
-                    (vma->vm_flags & vm_bad_flags))
-                        goto out;
-
-                if (opt == PR_SET_MM_START_DATA)
-                        mm->start_data = addr;
-                else
-                        mm->end_data = addr;
+                mm->start_data = addr;
                 break;
-
-        case PR_SET_MM_START_STACK:
-
-#ifdef CONFIG_STACK_GROWSUP
-                vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP;
-#else
-                vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN;
-#endif
-                if ((vma->vm_flags & vm_req_flags) != vm_req_flags)
-                        goto out;
-
-                mm->start_stack = addr;
+        case PR_SET_MM_END_DATA:
+                mm->end_data = addr;
                 break;
 
         case PR_SET_MM_START_BRK:
@@ -1881,16 +1908,77 @@ static int prctl_set_mm(int opt, unsigned long addr,
                 mm->brk = addr;
                 break;
 
+        /*
+         * If command line arguments and environment
+         * are placed somewhere else on stack, we can
+         * set them up here, ARG_START/END to setup
+         * command line argumets and ENV_START/END
+         * for environment.
+         */
+        case PR_SET_MM_START_STACK:
+        case PR_SET_MM_ARG_START:
+        case PR_SET_MM_ARG_END:
+        case PR_SET_MM_ENV_START:
+        case PR_SET_MM_ENV_END:
+                if (!vma) {
+                        error = -EFAULT;
+                        goto out;
+                }
+#ifdef CONFIG_STACK_GROWSUP
+                if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSUP, 0))
+#else
+                if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSDOWN, 0))
+#endif
+                        goto out;
+                if (opt == PR_SET_MM_START_STACK)
+                        mm->start_stack = addr;
+                else if (opt == PR_SET_MM_ARG_START)
+                        mm->arg_start = addr;
+                else if (opt == PR_SET_MM_ARG_END)
+                        mm->arg_end = addr;
+                else if (opt == PR_SET_MM_ENV_START)
+                        mm->env_start = addr;
+                else if (opt == PR_SET_MM_ENV_END)
+                        mm->env_end = addr;
+                break;
+
+        /*
+         * This doesn't move auxiliary vector itself
+         * since it's pinned to mm_struct, but allow
+         * to fill vector with new values. It's up
+         * to a caller to provide sane values here
+         * otherwise user space tools which use this
+         * vector might be unhappy.
+         */
+        case PR_SET_MM_AUXV: {
+                unsigned long user_auxv[AT_VECTOR_SIZE];
+
+                if (arg4 > sizeof(user_auxv))
+                        goto out;
+                up_read(&mm->mmap_sem);
+
+                if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
+                        return -EFAULT;
+
+                /* Make sure the last entry is always AT_NULL */
+                user_auxv[AT_VECTOR_SIZE - 2] = 0;
+                user_auxv[AT_VECTOR_SIZE - 1] = 0;
+
+                BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
+
+                task_lock(current);
+                memcpy(mm->saved_auxv, user_auxv, arg4);
+                task_unlock(current);
+
+                return 0;
+        }
         default:
-                error = -EINVAL;
                 goto out;
         }
 
         error = 0;
-
 out:
         up_read(&mm->mmap_sem);
-
         return error;
 }
 #else /* CONFIG_CHECKPOINT_RESTORE */
@@ -2114,7 +2202,6 @@ int orderly_poweroff(bool force)
                 NULL
         };
         int ret = -ENOMEM;
-        struct subprocess_info *info;
 
         if (argv == NULL) {
                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
@@ -2122,18 +2209,16 @@ int orderly_poweroff(bool force)
                 goto out;
         }
 
-        info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
-        if (info == NULL) {
-                argv_free(argv);
-                goto out;
-        }
-
-        call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
+        ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
+                                      NULL, argv_cleanup, NULL);
+out:
+        if (likely(!ret))
+                return 0;
 
-        ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
+        if (ret == -ENOMEM)
+                argv_free(argv);
 
-  out:
-        if (ret && force) {
+        if (force) {
                 printk(KERN_WARNING "Failed to start orderly shutdown: "
                        "forcing the issue\n");