Commits
Reinette Chatre committed 327460322c7
x86/resctrl: Prevent possible overrun during bitmap operations
commit 32f010deab575199df4ebe7b6aec20c17bb7eccd upstream.
While the DOC at the beginning of lib/bitmap.c explicitly states that
"The number of valid bits in a given bitmap does _not_ need to be an
exact multiple of BITS_PER_LONG.", some of the bitmap operations do
indeed access BITS_PER_LONG portions of the provided bitmap no matter
the size of the provided bitmap.
For example, if find_first_bit() is provided with an 8 bit bitmap the
operation will access BITS_PER_LONG bits from the provided bitmap. While
the operation ensures that these extra bits do not affect the result,
the memory is still accessed.
The capacity bitmasks (CBMs) are typically stored in u32 since they
can never exceed 32 bits. A few instances exist where a bitmap_*
operation is performed on a CBM by simply pointing the bitmap operation
to the stored u32 value.
The consequence of this pattern is that some bitmap_* operations will
access out-of-bounds memory when interacting with the provided CBM.
This same issue has previously been addressed with commit 49e00eee0061
("x86/intel_rdt: Fix out-of-bounds memory access in CBM tests")
but at that time not all instances of the issue were fixed.
Fix this by using an unsigned long to store the capacity bitmask data
that is passed to bitmap functions.
Fixes: e651901187ab ("x86/intel_rdt: Introduce "bit_usage" to display cache allocations details")
Fixes: f4e80d67a527 ("x86/intel_rdt: Resctrl files reflect pseudo-locked information")
Fixes: 95f0b77efa57 ("x86/intel_rdt: Initialize new resource group with sane defaults")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable <stable@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/58c9b6081fd9bf599af0dfc01a6fdd335768efef.1560975645.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>