[patch 01/16] Fix get_unmapped_area sanity tests

Chris Wright
2005-05-23T23:26:16Z

Fix get_unmapped_area sanity tests

As noted by Chris Wright, we need to do the full range of tests regardless
of whether MAP_FIXED is set or not, so re-organize get_unmapped_area()
slightly to do the sanity checks unconditionally.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
include/linux/err.h | 4 ++-
mm/mmap.c | 59 +++++++++++++++++++++++++++-------------------------
2 files changed, 34 insertions(+), 29 deletions(-)

--- linux-2.6.11.10.orig/include/linux/err.h 2005-05-16 10:51:42.000000000 -0700
+++ linux-2.6.11.10/include/linux/err.h 2005-05-20 10:14:06.838521528 -0700
@@ -13,6 +13,8 @@
* This should be a per-architecture thing, to allow different
* error and pointer decisions.
*/
+#define IS_ERR_VALUE(x) unlikely((x) > (unsigned long)-1000L)
+
static inline void *ERR_PTR(long error)
{
return (void *) error;
@@ -25,7 +27,7 @@

static inline long IS_ERR(const void *ptr)
{
- return unlikely((unsigned long)ptr > (unsigned long)-1000L);
+ return IS_ERR_VALUE((unsigned long)ptr);
}

#endif /* _LINUX_ERR_H */
--- linux-2.6.11.10.orig/mm/mmap.c 2005-05-16 10:51:55.000000000 -0700
+++ linux-2.6.11.10/mm/mmap.c 2005-05-20 10:40:34.071225480 -0700
@@ -1315,37 +1315,40 @@
get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
- if (flags & MAP_FIXED) {
- unsigned long ret;
+ unsigned long ret;

- if (addr > TASK_SIZE - len)
- return -ENOMEM;
- if (addr & ~PAGE_MASK)
- return -EINVAL;
- if (file && is_file_hugepages(file)) {
- /*
- * Check if the given range is hugepage aligned, and
- * can be made suitable for hugepages.
- */
- ret = prepare_hugepage_range(addr, len);
- } else {
- /*
- * Ensure that a normal request is not falling in a
- * reserved hugepage range. For some archs like IA-64,
- * there is a separate region for hugepages.
- */
- ret = is_hugepage_only_range(addr, len);
- }
- if (ret)
- return -EINVAL;
- return addr;
- }
+ if (!(flags & MAP_FIXED)) {
+ unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);

- if (file && file->f_op && file->f_op->get_unmapped_area)
- return file->f_op->get_unmapped_area(file, addr, len,
- pgoff, flags);
+ get_area = current->mm->get_unmapped_area;
+ if (file && file->f_op && file->f_op->get_unmapped_area)
+ get_area = file->f_op->get_unmapped_area;
+ addr = get_area(file, addr, len, pgoff, flags);
+ if (IS_ERR_VALUE(addr))
+ return addr;
+ }

- return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+ if (addr > TASK_SIZE - len)
+ return -ENOMEM;
+ if (addr & ~PAGE_MASK)
+ return -EINVAL;
+ if (file && is_file_hugepages(file)) {
+ /*
+ * Check if the given range is hugepage aligned, and
+ * can be made suitable for hugepages.
+ */
+ ret = prepare_hugepage_range(addr, len);
+ } else {
+ /*
+ * Ensure that a normal request is not falling in a
+ * reserved hugepage range. For some archs like IA-64,
+ * there is a separate region for hugepages.
+ */
+ ret = is_hugepage_only_range(addr, len);
+ }
+ if (ret)
+ return -EINVAL;
+ return addr;
}

EXPORT_SYMBOL(get_unmapped_area);