patches.android/android-0029-ashmem-Fix-ASHMEM_SET_PROT_MASK.patch

From 56f76fc68492af718fff88927bc296635d634b78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>
Date: Tue, 20 Dec 2011 16:49:50 -0800
Subject: ashmem: Fix ASHMEM_SET_PROT_MASK.
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit
Patch-mainline: HEAD
Git-commit: 56f76fc68492af718fff88927bc296635d634b78

Signed-off-by: Arve Hjønnevåg <arve@android.com>
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 6f1a0bb..0b923b0 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -236,6 +236,13 @@ out:
 	return ret;
 }
 
+static inline unsigned long
+calc_vm_may_flags(unsigned long prot)
+{
+	return _calc_vm_trans(prot, PROT_READ,  VM_MAYREAD ) |
+	       _calc_vm_trans(prot, PROT_WRITE, VM_MAYWRITE) |
+	       _calc_vm_trans(prot, PROT_EXEC,  VM_MAYEXEC);
+}
 
 static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
@@ -251,10 +258,12 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
 	}
 
 	/* requested protection bits must match our allowed protection mask */
-	if (unlikely((vma->vm_flags & ~asma->prot_mask) & PROT_MASK)) {
+	if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) &
+						calc_vm_prot_bits(PROT_MASK))) {
 		ret = -EPERM;
 		goto out;
 	}
+	vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask);
 
 	if (!asma->file) {
 		char *name = ASHMEM_NAME_DEF;