selinuxfs snprintf() misuses

a) %d does _not_ produce a page worth of output
b) snprintf() doesn't return negatives - it used to in old glibc, but
that's the kernel...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 29 deletions

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 4e93f9ef970b..3ad290251288 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1259,12 +1259,8 @@ static int sel_make_bools(void)
                 if (!inode)
                         goto out;
 
-                ret = -EINVAL;
-                len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
-                if (len < 0)
-                        goto out;
-
                 ret = -ENAMETOOLONG;
+                len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
                 if (len >= PAGE_SIZE)
                         goto out;
 
@@ -1557,19 +1553,10 @@ static inline u32 sel_ino_to_perm(unsigned long ino)
 static ssize_t sel_read_class(struct file *file, char __user *buf,
                                 size_t count, loff_t *ppos)
 {
-        ssize_t rc, len;
-        char *page;
         unsigned long ino = file->f_path.dentry->d_inode->i_ino;
-
-        page = (char *)__get_free_page(GFP_KERNEL);
-        if (!page)
-                return -ENOMEM;
-
-        len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));
-        rc = simple_read_from_buffer(buf, count, ppos, page, len);
-        free_page((unsigned long)page);
-
-        return rc;
+        char res[TMPBUFLEN];
+        ssize_t len = snprintf(res, sizeof(res), "%d", sel_ino_to_class(ino));
+        return simple_read_from_buffer(buf, count, ppos, res, len);
 }
 
 static const struct file_operations sel_class_ops = {
@@ -1580,19 +1567,10 @@ static const struct file_operations sel_class_ops = {
 static ssize_t sel_read_perm(struct file *file, char __user *buf,
                                 size_t count, loff_t *ppos)
 {
-        ssize_t rc, len;
-        char *page;
         unsigned long ino = file->f_path.dentry->d_inode->i_ino;
-
-        page = (char *)__get_free_page(GFP_KERNEL);
-        if (!page)
-                return -ENOMEM;
-
-        len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_perm(ino));
-        rc = simple_read_from_buffer(buf, count, ppos, page, len);
-        free_page((unsigned long)page);
-
-        return rc;
+        char res[TMPBUFLEN];
+        ssize_t len = snprintf(res, sizeof(res), "%d", sel_ino_to_perm(ino));
+        return simple_read_from_buffer(buf, count, ppos, res, len);
 }
 
 static const struct file_operations sel_perm_ops = {