mm/mempolicy.c: fix error handling in set_mempolicy and mbind.
In the case that compat_get_bitmap fails we do not want to copy the bitmap to the user as it will contain uninitialized stack data and leak sensitive data. Signed-off-by: Chris Salls <salls@cs.ucsb.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1529,7 +1529,6 @@ COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
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COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
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compat_ulong_t, maxnode)
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{
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long err = 0;
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unsigned long __user *nm = NULL;
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unsigned long nr_bits, alloc_size;
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DECLARE_BITMAP(bm, MAX_NUMNODES);
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@ -1538,14 +1537,13 @@ COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
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alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
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if (nmask) {
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err = compat_get_bitmap(bm, nmask, nr_bits);
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if (compat_get_bitmap(bm, nmask, nr_bits))
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return -EFAULT;
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nm = compat_alloc_user_space(alloc_size);
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err |= copy_to_user(nm, bm, alloc_size);
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if (copy_to_user(nm, bm, alloc_size))
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return -EFAULT;
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}
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if (err)
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return -EFAULT;
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return sys_set_mempolicy(mode, nm, nr_bits+1);
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}
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@ -1553,7 +1551,6 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
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compat_ulong_t, mode, compat_ulong_t __user *, nmask,
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compat_ulong_t, maxnode, compat_ulong_t, flags)
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{
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long err = 0;
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unsigned long __user *nm = NULL;
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unsigned long nr_bits, alloc_size;
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nodemask_t bm;
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@ -1562,14 +1559,13 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
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alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
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if (nmask) {
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err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
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if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
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return -EFAULT;
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nm = compat_alloc_user_space(alloc_size);
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err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
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if (copy_to_user(nm, nodes_addr(bm), alloc_size))
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return -EFAULT;
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}
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if (err)
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return -EFAULT;
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return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
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}
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