perf_counter: Fix perf_copy_attr() pointer arithmetic
There is still some weird code in per_copy_attr(). Which supposedly checks that all bytes trailing a struct are zero. It doesn't seem to get pointer arithmetic right. Since it increments an iterating pointer by sizeof(unsigned long) rather than 1. Signed-off-by: Ian Schram <ischram@telenet.be> [ v2: clean up the messy PTR_ALIGN logic as well. ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@kernel.org> # for v2.6.31.x LKML-Reference: <4AB3DEE2.3030600@telenet.be> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -4208,8 +4208,8 @@ done:
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static int perf_copy_attr(struct perf_counter_attr __user *uattr,
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struct perf_counter_attr *attr)
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{
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int ret;
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u32 size;
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int ret;
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if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
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return -EFAULT;
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@ -4234,19 +4234,19 @@ static int perf_copy_attr(struct perf_counter_attr __user *uattr,
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/*
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* If we're handed a bigger struct than we know of,
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* ensure all the unknown bits are 0.
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* ensure all the unknown bits are 0 - i.e. new
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* user-space does not rely on any kernel feature
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* extensions we dont know about yet.
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*/
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if (size > sizeof(*attr)) {
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unsigned long val;
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unsigned long __user *addr;
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unsigned long __user *end;
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unsigned char __user *addr;
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unsigned char __user *end;
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unsigned char val;
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addr = PTR_ALIGN((void __user *)uattr + sizeof(*attr),
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sizeof(unsigned long));
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end = PTR_ALIGN((void __user *)uattr + size,
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sizeof(unsigned long));
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addr = (void __user *)uattr + sizeof(*attr);
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end = (void __user *)uattr + size;
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for (; addr < end; addr += sizeof(unsigned long)) {
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for (; addr < end; addr++) {
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ret = get_user(val, addr);
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if (ret)
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return ret;
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