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[PATCH v1 3/3] perf/x86/intel/pt: Do validate the size of a kernel address filter

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Right now, the kernel address filters in PT are prone to integer overflow
that may happen in adding filter's size to its offset to obtain the end
of the range. Such an overflow would also throw a #GP in the PT event
configuration path.

Fix this by explicitly validating the result of this calculation.

Cc: stable@vger.kernel.org # v4.7
Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 arch/x86/events/intel/pt.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 1f94963a28..861a7d9cb6 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -1089,8 +1089,13 @@ static int pt_event_addr_filters_validate(struct list_head *filters)
 		if (!filter->range || !filter->size)
 			return -EOPNOTSUPP;
 
-		if (!filter->inode && !valid_kernel_ip(filter->offset))
-			return -EINVAL;
+		if (!filter->inode) {
+			if (!valid_kernel_ip(filter->offset))
+				return -EINVAL;
+
+			if (!valid_kernel_ip(filter->offset + filter->size))
+				return -EINVAL;
+		}
 
 		if (++range > pt_cap_get(PT_CAP_num_address_ranges))
 			return -EOPNOTSUPP;
-- 
2.9.3

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[PATCH v1 0/3] perf/x86/intel/pt: Address filtering fixes for perf/urgent Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-09-15 17:30 +0200
  [PATCH v1 3/3] perf/x86/intel/pt: Do validate the size of a kernel address filter Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-09-15 17:30 +0200
    [tip:perf/urgent] perf/x86/intel/pt: Do validate the size of a  kernel address filter tip-bot for Alexander Shishkin <tipbot@zytor.com> - 2016-09-16 14:10 +0200
  [PATCH v1 1/3] perf/x86/intel/pt: Fix an off-by-one in address filter configuration Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-09-15 17:30 +0200
    [tip:perf/urgent] perf/x86/intel/pt: Fix an off-by-one in address  filter configuration tip-bot for Alexander Shishkin <tipbot@zytor.com> - 2016-09-16 14:00 +0200

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