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-rw-r--r--fs/attr.c7
-rw-r--r--fs/xattr.c7
-rw-r--r--include/linux/fs.h13
-rw-r--r--mm/filemap.c14
4 files changed, 37 insertions, 4 deletions
diff --git a/fs/attr.c b/fs/attr.c
index 91dbe2a107f2..caf2aa521e2b 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -175,6 +175,13 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
return -EPERM;
}
+ if ((ia_valid & ATTR_MODE)) {
+ mode_t amode = attr->ia_mode;
+ /* Flag setting protected by i_mutex */
+ if (is_sxid(amode))
+ inode->i_flags &= ~S_NOSEC;
+ }
+
now = current_fs_time(inode->i_sb);
attr->ia_ctime = now;
diff --git a/fs/xattr.c b/fs/xattr.c
index 4be2e7666d02..f060663ab70c 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -91,7 +91,11 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
{
struct inode *inode = dentry->d_inode;
int error = -EOPNOTSUPP;
+ int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN);
+ if (issec)
+ inode->i_flags &= ~S_NOSEC;
if (inode->i_op->setxattr) {
error = inode->i_op->setxattr(dentry, name, value, size, flags);
if (!error) {
@@ -99,8 +103,7 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
security_inode_post_setxattr(dentry, name, value,
size, flags);
}
- } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
- XATTR_SECURITY_PREFIX_LEN)) {
+ } else if (issec) {
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
error = security_inode_setsecurity(inode, suffix, value,
size, flags);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 573028df050d..c55d6b7cd5d6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -237,6 +237,7 @@ struct inodes_stat_t {
#define S_PRIVATE 512 /* Inode is fs-internal */
#define S_IMA 1024 /* Inode has an associated IMA struct */
#define S_AUTOMOUNT 2048 /* Automount/referral quasi-directory */
+#define S_NOSEC 4096 /* no suid or xattr security attributes */
/*
* Note that nosuid etc flags are inode-specific: setting some file-system
@@ -273,6 +274,7 @@ struct inodes_stat_t {
#define IS_PRIVATE(inode) ((inode)->i_flags & S_PRIVATE)
#define IS_IMA(inode) ((inode)->i_flags & S_IMA)
#define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT)
+#define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC)
/* the read-only stuff doesn't really belong here, but any other place is
probably as bad and I don't want to create yet another include file. */
@@ -2582,5 +2584,16 @@ int __init get_filesystem_list(char *buf);
#define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
(flag & __FMODE_NONOTIFY)))
+static inline int is_sxid(mode_t mode)
+{
+ return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
+}
+
+static inline void inode_has_no_xattr(struct inode *inode)
+{
+ if (!is_sxid(inode->i_mode))
+ inode->i_flags |= S_NOSEC;
+}
+
#endif /* __KERNEL__ */
#endif /* _LINUX_FS_H */
diff --git a/mm/filemap.c b/mm/filemap.c
index dac95a24deac..d7b10578a64b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1982,16 +1982,26 @@ static int __remove_suid(struct dentry *dentry, int kill)
int file_remove_suid(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
- int killsuid = should_remove_suid(dentry);
- int killpriv = security_inode_need_killpriv(dentry);
+ struct inode *inode = dentry->d_inode;
+ int killsuid;
+ int killpriv;
int error = 0;
+ /* Fast path for nothing security related */
+ if (IS_NOSEC(inode))
+ return 0;
+
+ killsuid = should_remove_suid(dentry);
+ killpriv = security_inode_need_killpriv(dentry);
+
if (killpriv < 0)
return killpriv;
if (killpriv)
error = security_inode_killpriv(dentry);
if (!error && killsuid)
error = __remove_suid(dentry, killsuid);
+ if (!error)
+ inode->i_flags |= S_NOSEC;
return error;
}