LSM: Add security_path_chmod() and security_path_chown().

This patch allows pathname based LSM modules to check chmod()/chown()
operations. Since notify_change() does not receive "struct vfsmount *",
we add security_path_chmod() and security_path_chown() to the caller of
notify_change().

These hooks are used by TOMOYO.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/fs/open.c b/fs/open.c
index 4f01e06227c6..b5c294d35bd1 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -616,6 +616,9 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
         err = mnt_want_write_file(file);
         if (err)
                 goto out_putf;
+        err = security_path_chmod(dentry, file->f_vfsmnt, mode);
+        if (err)
+                goto out_drop_write;
         mutex_lock(&inode->i_mutex);
         if (mode == (mode_t) -1)
                 mode = inode->i_mode;
@@ -623,6 +626,7 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
         err = notify_change(dentry, &newattrs);
         mutex_unlock(&inode->i_mutex);
+out_drop_write:
         mnt_drop_write(file->f_path.mnt);
 out_putf:
         fput(file);
@@ -645,6 +649,9 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode)
         error = mnt_want_write(path.mnt);
         if (error)
                 goto dput_and_out;
+        error = security_path_chmod(path.dentry, path.mnt, mode);
+        if (error)
+                goto out_drop_write;
         mutex_lock(&inode->i_mutex);
         if (mode == (mode_t) -1)
                 mode = inode->i_mode;
@@ -652,6 +659,7 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode)
         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
         error = notify_change(path.dentry, &newattrs);
         mutex_unlock(&inode->i_mutex);
+out_drop_write:
         mnt_drop_write(path.mnt);
 dput_and_out:
         path_put(&path);
@@ -700,7 +708,9 @@ SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
         error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(path.dentry, user, group);
+        error = security_path_chown(&path, user, group);
+        if (!error)
+                error = chown_common(path.dentry, user, group);
         mnt_drop_write(path.mnt);
 out_release:
         path_put(&path);
@@ -725,7 +735,9 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
         error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(path.dentry, user, group);
+        error = security_path_chown(&path, user, group);
+        if (!error)
+                error = chown_common(path.dentry, user, group);
         mnt_drop_write(path.mnt);
 out_release:
         path_put(&path);
@@ -744,7 +756,9 @@ SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group
         error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(path.dentry, user, group);
+        error = security_path_chown(&path, user, group);
+        if (!error)
+                error = chown_common(path.dentry, user, group);
         mnt_drop_write(path.mnt);
 out_release:
         path_put(&path);
@@ -767,7 +781,9 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
                 goto out_fput;
         dentry = file->f_path.dentry;
         audit_inode(NULL, dentry);
-        error = chown_common(dentry, user, group);
+        error = security_path_chown(&file->f_path, user, group);
+        if (!error)
+                error = chown_common(dentry, user, group);
         mnt_drop_write(file->f_path.mnt);
 out_fput:
         fput(file);