1 files changed, 131 insertions, 17 deletions

diff --git a/fs/compat.c b/fs/compat.c
index d0145ca27572..3f84d5f15889 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -51,6 +51,7 @@
 #include <linux/poll.h>
 #include <linux/mm.h>
 #include <linux/eventpoll.h>
+#include <linux/fs_struct.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -378,6 +379,34 @@ out:
         return error;
 }
 
+/*
+ * This is a copy of sys_ustat, just dealing with a structure layout.
+ * Given how simple this syscall is that apporach is more maintainable
+ * than the various conversion hacks.
+ */
+asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u)
+{
+        struct super_block *sb;
+        struct compat_ustat tmp;
+        struct kstatfs sbuf;
+        int err;
+
+        sb = user_get_super(new_decode_dev(dev));
+        if (!sb)
+                return -EINVAL;
+        err = vfs_statfs(sb->s_root, &sbuf);
+        drop_super(sb);
+        if (err)
+                return err;
+
+        memset(&tmp, 0, sizeof(struct compat_ustat));
+        tmp.f_tfree = sbuf.f_bfree;
+        tmp.f_tinode = sbuf.f_ffree;
+        if (copy_to_user(u, &tmp, sizeof(struct compat_ustat)))
+                return -EFAULT;
+        return 0;
+}
+
 static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
 {
         if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
@@ -1167,16 +1196,12 @@ out:
         return ret;
 }
 
-asmlinkage ssize_t
-compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
+static size_t compat_readv(struct file *file,
+                           const struct compat_iovec __user *vec,
+                           unsigned long vlen, loff_t *pos)
 {
-        struct file *file;
         ssize_t ret = -EBADF;
 
-        file = fget(fd);
-        if (!file)
-                return -EBADF;
-
         if (!(file->f_mode & FMODE_READ))
                 goto out;
 
@@ -1184,25 +1209,56 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsign
         if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
                 goto out;
 
-        ret = compat_do_readv_writev(READ, file, vec, vlen, &file->f_pos);
+        ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
 
 out:
         if (ret > 0)
                 add_rchar(current, ret);
         inc_syscr(current);
-        fput(file);
         return ret;
 }
 
 asmlinkage ssize_t
-compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
+compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
+                 unsigned long vlen)
 {
         struct file *file;
-        ssize_t ret = -EBADF;
+        int fput_needed;
+        ssize_t ret;
 
-        file = fget(fd);
+        file = fget_light(fd, &fput_needed);
         if (!file)
                 return -EBADF;
+        ret = compat_readv(file, vec, vlen, &file->f_pos);
+        fput_light(file, fput_needed);
+        return ret;
+}
+
+asmlinkage ssize_t
+compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
+                  unsigned long vlen, u32 pos_low, u32 pos_high)
+{
+        loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+        struct file *file;
+        int fput_needed;
+        ssize_t ret;
+
+        if (pos < 0)
+                return -EINVAL;
+        file = fget_light(fd, &fput_needed);
+        if (!file)
+                return -EBADF;
+        ret = compat_readv(file, vec, vlen, &pos);
+        fput_light(file, fput_needed);
+        return ret;
+}
+
+static size_t compat_writev(struct file *file,
+                            const struct compat_iovec __user *vec,
+                            unsigned long vlen, loff_t *pos)
+{
+        ssize_t ret = -EBADF;
+
         if (!(file->f_mode & FMODE_WRITE))
                 goto out;
 
@@ -1210,13 +1266,47 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, unsig
         if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
                 goto out;
 
-        ret = compat_do_readv_writev(WRITE, file, vec, vlen, &file->f_pos);
+        ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
 
 out:
         if (ret > 0)
                 add_wchar(current, ret);
         inc_syscw(current);
-        fput(file);
+        return ret;
+}
+
+asmlinkage ssize_t
+compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec,
+                  unsigned long vlen)
+{
+        struct file *file;
+        int fput_needed;
+        ssize_t ret;
+
+        file = fget_light(fd, &fput_needed);
+        if (!file)
+                return -EBADF;
+        ret = compat_writev(file, vec, vlen, &file->f_pos);
+        fput_light(file, fput_needed);
+        return ret;
+}
+
+asmlinkage ssize_t
+compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec,
+                   unsigned long vlen, u32 pos_low, u32 pos_high)
+{
+        loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+        struct file *file;
+        int fput_needed;
+        ssize_t ret;
+
+        if (pos < 0)
+                return -EINVAL;
+        file = fget_light(fd, &fput_needed);
+        if (!file)
+                return -EBADF;
+        ret = compat_writev(file, vec, vlen, &pos);
+        fput_light(file, fput_needed);
         return ret;
 }
 
@@ -1392,27 +1482,36 @@ int compat_do_execve(char * filename,
 {
         struct linux_binprm *bprm;
         struct file *file;
+        struct files_struct *displaced;
         int retval;
 
+        retval = unshare_files(&displaced);
+        if (retval)
+                goto out_ret;
+
         retval = -ENOMEM;
         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
         if (!bprm)
-                goto out_ret;
+                goto out_files;
 
         retval = mutex_lock_interruptible(&current->cred_exec_mutex);
         if (retval < 0)
                 goto out_free;
+        current->in_execve = 1;
 
         retval = -ENOMEM;
         bprm->cred = prepare_exec_creds();
         if (!bprm->cred)
                 goto out_unlock;
-        check_unsafe_exec(bprm, current->files);
+
+        retval = check_unsafe_exec(bprm);
+        if (retval)
+                goto out_unlock;
 
         file = open_exec(filename);
         retval = PTR_ERR(file);
         if (IS_ERR(file))
-                goto out_unlock;
+                goto out_unmark;
 
         sched_exec();
 
@@ -1454,9 +1553,15 @@ int compat_do_execve(char * filename,
                 goto out;
 
         /* execve succeeded */
+        write_lock(&current->fs->lock);
+        current->fs->in_exec = 0;
+        write_unlock(&current->fs->lock);
+        current->in_execve = 0;
         mutex_unlock(&current->cred_exec_mutex);
         acct_update_integrals(current);
         free_bprm(bprm);
+        if (displaced)
+                put_files_struct(displaced);
         return retval;
 
 out:
@@ -1469,12 +1574,21 @@ out_file:
                 fput(bprm->file);
         }
 
+out_unmark:
+        write_lock(&current->fs->lock);
+        current->fs->in_exec = 0;
+        write_unlock(&current->fs->lock);
+
 out_unlock:
+        current->in_execve = 0;
         mutex_unlock(&current->cred_exec_mutex);
 
 out_free:
         free_bprm(bprm);
 
+out_files:
+        if (displaced)
+                reset_files_struct(displaced);
 out_ret:
         return retval;
 }