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-rw-r--r--fs/fat/file.c47
1 files changed, 44 insertions, 3 deletions
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 69a83b5..c614175 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -155,6 +155,42 @@ out:
return err;
}
+static int check_mode(const struct msdos_sb_info *sbi, mode_t mode)
+{
+ mode_t req = mode & ~S_IFMT;
+
+ /*
+ * Of the r and x bits, all (subject to umask) must be present. Of the
+ * w bits, either all (subject to umask) or none must be present.
+ */
+
+ if (S_ISREG(mode)) {
+ req &= ~sbi->options.fs_fmask;
+
+ if ((req & (S_IRUGO | S_IXUGO)) !=
+ ((S_IRUGO | S_IXUGO) & ~sbi->options.fs_fmask))
+ return -EPERM;
+
+ if ((req & S_IWUGO) != 0 &&
+ (req & S_IWUGO) != (S_IWUGO & ~sbi->options.fs_fmask))
+ return -EPERM;
+ } else if (S_ISDIR(mode)) {
+ req &= ~sbi->options.fs_dmask;
+
+ if ((req & (S_IRUGO | S_IXUGO)) !=
+ ((S_IRUGO | S_IXUGO) & ~sbi->options.fs_dmask))
+ return -EPERM;
+
+ if ((req & S_IWUGO) != 0 &&
+ (req & S_IWUGO) != (S_IWUGO & ~sbi->options.fs_dmask))
+ return -EPERM;
+ } else {
+ return -EPERM;
+ }
+
+ return 0;
+}
+
int fat_notify_change(struct dentry *dentry, struct iattr *attr)
{
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
@@ -186,9 +222,7 @@ int fat_notify_change(struct dentry *dentry, struct iattr *attr)
if (((attr->ia_valid & ATTR_UID) &&
(attr->ia_uid != sbi->options.fs_uid)) ||
((attr->ia_valid & ATTR_GID) &&
- (attr->ia_gid != sbi->options.fs_gid)) ||
- ((attr->ia_valid & ATTR_MODE) &&
- (attr->ia_mode & ~MSDOS_VALID_MODE)))
+ (attr->ia_gid != sbi->options.fs_gid)))
error = -EPERM;
if (error) {
@@ -196,6 +230,13 @@ int fat_notify_change(struct dentry *dentry, struct iattr *attr)
error = 0;
goto out;
}
+
+ if (attr->ia_valid & ATTR_MODE) {
+ error = check_mode(sbi, attr->ia_mode);
+ if (error != 0 && !sbi->options.quiet)
+ goto out;
+ }
+
error = inode_setattr(inode, attr);
if (error)
goto out;
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