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authorAl Viro <viro@zeniv.linux.org.uk>2010-12-17 07:44:05 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2011-01-12 20:06:58 -0500
commitcccb5a1e698535fa5a734ffe21c7061c97f8d8c5 (patch)
treebbb369670469641237e672217bc0db423c454979 /fs/read_write.c
parent208898c17a97610ce1c01b1cc58e51802a1d52c3 (diff)
downloadlinux-cccb5a1e698535fa5a734ffe21c7061c97f8d8c5.tar.gz
fix signedness mess in rw_verify_area() on 64bit architectures
... and clean the unsigned-f_pos code, while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c27
1 files changed, 11 insertions, 16 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 5d431bacbea..5520f8ad550 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -30,18 +30,9 @@ 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)
+static inline int unsigned_offsets(struct file *file)
{
- /*
- * 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;
+ return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
/**
@@ -75,7 +66,7 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
break;
}
- if (offset < 0 && __negative_fpos_check(file, offset, 0))
+ if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
if (offset > inode->i_sb->s_maxbytes)
return -EINVAL;
@@ -152,7 +143,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
offset += file->f_pos;
}
retval = -EINVAL;
- if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) {
+ if (offset >= 0 || unsigned_offsets(file)) {
if (offset != file->f_pos) {
file->f_pos = offset;
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))
return retval;
pos = *ppos;
- if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) {
- retval = __negative_fpos_check(file, pos, count);
- if (retval)
+ if (unlikely(pos < 0)) {
+ if (!unsigned_offsets(file))
+ 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;
}