---

yaml --- r: 9153 b: refs/heads/master c: 7e2cff4 h: refs/heads/master i: 9151: 8640aa5 v: v3
git-mirror · Sep 21, 2005 · 3b76aef · 3b76aef
1 parent 3be5917
commit 3b76aef
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Showing 3 changed files with 4 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7e871b6c8f1f4fda41e51ef86147facecac3be9f
+refs/heads/master: 7e2cff42cfac27c25202648c5c89f9171e5bc085
diff --git a/trunk/include/linux/mm.h b/trunk/include/linux/mm.h
@@ -136,6 +136,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_EXEC		0x00000004
 #define VM_SHARED	0x00000008
 
+/* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
 #define VM_MAYREAD	0x00000010	/* limits for mprotect() etc */
 #define VM_MAYWRITE	0x00000020
 #define VM_MAYEXEC	0x00000040

diff --git a/trunk/mm/mprotect.c b/trunk/mm/mprotect.c
@@ -248,7 +248,8 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
 
 		newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
 
-		if ((newflags & ~(newflags >> 4)) & 0xf) {
+		/* newflags >> 4 shift VM_MAY% in place of VM_% */
+		if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
 			error = -EACCES;
 			goto out;
 		}