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fix signedness mess in rw_verify_area() on 64bit architectures

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... and clean the unsigned-f_pos code, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2010-12-17 07:44:05 -05:00
parent 208898c17a
commit cccb5a1e69
1 changed files with 11 additions and 16 deletions
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27
fs/read_write.c
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@ -30,18 +30,9 @@ const struct file_operations generic_ro_fops = {
EXPORT_SYMBOL(generic_ro_fops); EXPORT_SYMBOL(generic_ro_fops);
static int static inline int unsigned_offsets(struct file *file)
__negative_fpos_check(struct file *file, loff_t pos, size_t count)
{ {
/* return file->f_mode & FMODE_UNSIGNED_OFFSET;
* 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;
} }
/** /**
@ -75,7 +66,7 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
break; break;
} }
if (offset < 0 && __negative_fpos_check(file, offset, 0)) if (offset < 0 && !unsigned_offsets(file))
return -EINVAL; return -EINVAL;
if (offset > inode->i_sb->s_maxbytes) if (offset > inode->i_sb->s_maxbytes)
return -EINVAL; return -EINVAL;
@ -152,7 +143,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
offset += file->f_pos; offset += file->f_pos;
} }
retval = -EINVAL; retval = -EINVAL;
if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) { if (offset >= 0 || unsigned_offsets(file)) {
if (offset != file->f_pos) { if (offset != file->f_pos) {
file->f_pos = offset; file->f_pos = offset;
file->f_version = 0; file->f_version = 0;
@ -252,9 +243,13 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
if (unlikely((ssize_t) count < 0)) if (unlikely((ssize_t) count < 0))
return retval; return retval;
pos = *ppos; pos = *ppos;
if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) { if (unlikely(pos < 0)) {
retval = __negative_fpos_check(file, pos, count); if (!unsigned_offsets(file))
if (retval) return retval;
if (count >= -pos) /* both values are in 0..LLONG_MAX */
return -EOVERFLOW;
} else if (unlikely((loff_t) (pos + count) < 0)) {
if (!unsigned_offsets(file))
return retval; return retval;
} }