convert ecryptfs

[pandora-kernel.git] / fs / read_write.c

diff --git a/fs/read_write.c b/fs/read_write.c
index e757ef2..9cd9d14 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -31,6 +31,20 @@ const struct file_operations generic_ro_fops = {
 
 EXPORT_SYMBOL(generic_ro_fops);
 
+static int
+__negative_fpos_check(struct file *file, loff_t pos, size_t count)
+{
+       /*
+        * pos or pos+count is negative here, check overflow.
+        * too big "count" will be caught in rw_verify_area().
+        */
+       if ((pos < 0) && (pos + count < pos))
+               return -EOVERFLOW;
+       if (file->f_mode & FMODE_UNSIGNED_OFFSET)
+               return 0;
+       return -EINVAL;
+}
+
 /**
  * generic_file_llseek_unlocked - lockless generic llseek implementation
  * @file:      file structure to seek on
@@ -62,7 +76,9 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
                break;
        }
 
-       if (offset < 0 || offset > inode->i_sb->s_maxbytes)
+       if (offset < 0 && __negative_fpos_check(file, offset, 0))
+               return -EINVAL;
+       if (offset > inode->i_sb->s_maxbytes)
                return -EINVAL;
 
        /* Special lock needed here? */
@@ -137,7 +153,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
                        offset += file->f_pos;
        }
        retval = -EINVAL;
-       if (offset >= 0) {
+       if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) {
                if (offset != file->f_pos) {
                        file->f_pos = offset;
                        file->f_version = 0;
@@ -221,6 +237,7 @@ bad:
 }
 #endif
 
+
 /*
  * rw_verify_area doesn't like huge counts. We limit
  * them to something that fits in "int" so that others
@@ -238,8 +255,11 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
        if (unlikely((ssize_t) count < 0))
                return retval;
        pos = *ppos;
-       if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
-               return retval;
+       if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) {
+               retval = __negative_fpos_check(file, pos, count);
+               if (retval)
+                       return retval;
+       }
 
        if (unlikely(inode->i_flock && mandatory_lock(inode))) {
                retval = locks_mandatory_area(