From a1bead954c2163a45c45116fbbb74bb333eee186 Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@computergmbh.de>
Date: Wed, 6 Feb 2008 01:36:08 -0800
Subject: [PATCH] --- yaml --- r: 83371 b: refs/heads/master c:
 19c561a60ffe52df88dd63de0bff480ca094efe4 h: refs/heads/master i:   83369:
 0e5069508497efb4c1a5f0915334fb05a81c7c80   83367:
 5d66adb323386ccab49fe2e6744ac6ab57074fc8 v: v3

---
 [refs]              |  2 +-
 trunk/fs/fat/file.c | 47 ++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 7adf8c972280..73df52eda3f1 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 20292bc2c3feaee7f2e93911ffcb692732293894
+refs/heads/master: 19c561a60ffe52df88dd63de0bff480ca094efe4
diff --git a/trunk/fs/fat/file.c b/trunk/fs/fat/file.c
index 69a83b59dce8..c614175876e0 100644
--- a/trunk/fs/fat/file.c
+++ b/trunk/fs/fat/file.c
@@ -155,6 +155,42 @@ static int fat_cont_expand(struct inode *inode, loff_t size)
 	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;