ashmem: Validate ashmem memory with fops pointer
Validate the ashmem memory entry against f_op pointer
rather then comparing its name with path of the dentry.
This is to avoid any invalid access to ashmem area in cases
where some one deliberately set the dentry name to /ashmem.
Change-Id: I549c7743e63a416d2422236ca28834e64546fc93
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 808acd4..ee79ac8 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -766,11 +766,28 @@
}
#endif
+static const struct file_operations ashmem_fops = {
+ .owner = THIS_MODULE,
+ .open = ashmem_open,
+ .release = ashmem_release,
+ .read = ashmem_read,
+ .llseek = ashmem_llseek,
+ .mmap = ashmem_mmap,
+ .unlocked_ioctl = ashmem_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = compat_ashmem_ioctl,
+#endif
+};
+
+static struct miscdevice ashmem_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "ashmem",
+ .fops = &ashmem_fops,
+};
+
static int is_ashmem_file(struct file *file)
{
- char fname[256], *name;
- name = dentry_path(file->f_dentry, fname, 256);
- return strcmp(name, "/ashmem") ? 0 : 1;
+ return (file->f_op == &ashmem_fops);
}
int get_ashmem_file(int fd, struct file **filp, struct file **vm_file,
@@ -819,25 +836,6 @@
}
EXPORT_SYMBOL(put_ashmem_file);
-static const struct file_operations ashmem_fops = {
- .owner = THIS_MODULE,
- .open = ashmem_open,
- .release = ashmem_release,
- .read = ashmem_read,
- .llseek = ashmem_llseek,
- .mmap = ashmem_mmap,
- .unlocked_ioctl = ashmem_ioctl,
-#ifdef CONFIG_COMPAT
- .compat_ioctl = compat_ashmem_ioctl,
-#endif
-};
-
-static struct miscdevice ashmem_misc = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = "ashmem",
- .fops = &ashmem_fops,
-};
-
static int __init ashmem_init(void)
{
int ret;
