Don't allow mremap of zero-sized areas.

70faa195 · Linus Torvalds · e37d5b22 · 70faa195
Commit 70faa195 authored Jan 04, 2004 by Linus Torvalds
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mm/mremap.c mm/mremap.c +4 -0

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--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -315,6 +315,10 @@ unsigned long do_mremap(unsigned long addr,
 	old_len = PAGE_ALIGN(old_len);
 	new_len = PAGE_ALIGN(new_len);
+	/* Don't allow the degenerate cases */
+	if (!(old_len | new_len))
+		goto out;
 	/* new_addr is only valid if MREMAP_FIXED is specified */
 	if (flags & MREMAP_FIXED) {
 		if (new_addr & ~PAGE_MASK)