From c53412ee8c7ec31373a4176ff7f3a6b79296c05c Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 18 Aug 2016 16:30:28 -0300 Subject: [PATCH] perf evsel: Do not access outside hw cache name arrays We have to check if the values are >= *_MAX, not just >, fix it. From the bugzilla report: ''In file /tools/perf/util/evsel.c function __perf_evsel__hw_cache_name it appears that there is a bug that reads beyond the end of the buffer. The statement "if (type > PERF_COUNT_HW_CACHE_MAX)" allows type to be equal to the maximum value. Later, when statement "if (!perf_evsel__is_cache_op_valid(type, op))" is executed, the function can access array perf_evsel__hw_cache_stat[type] beyond the end of the buffer. It appears to me that the statement "if (type > PERF_COUNT_HW_CACHE_MAX)" should be "if (type >= PERF_COUNT_HW_CACHE_MAX)" Bug found with Coverity and manual code review. No attempts were made to execute the code with a maximum type value.'' Committer note: Testing it: $ perf record -e $(echo $(perf list cache | cut -d \[ -f1) | sed 's/ /,/g') usleep 1 [ perf record: Woken up 16 times to write data ] [ perf record: Captured and wrote 0.023 MB perf.data (34 samples) ] $ perf evlist L1-dcache-load-misses L1-dcache-loads L1-dcache-stores L1-icache-load-misses LLC-load-misses LLC-loads LLC-store-misses LLC-stores branch-load-misses branch-loads dTLB-load-misses dTLB-loads dTLB-store-misses dTLB-stores iTLB-load-misses iTLB-loads node-load-misses node-loads node-store-misses node-stores $ perf list cache List of pre-defined events (to be used in -e): L1-dcache-load-misses [Hardware cache event] L1-dcache-loads [Hardware cache event] L1-dcache-stores [Hardware cache event] L1-icache-load-misses [Hardware cache event] LLC-load-misses [Hardware cache event] LLC-loads [Hardware cache event] LLC-store-misses [Hardware cache event] LLC-stores [Hardware cache event] branch-load-misses [Hardware cache event] branch-loads [Hardware cache event] dTLB-load-misses [Hardware cache event] dTLB-loads [Hardware cache event] dTLB-store-misses [Hardware cache event] dTLB-stores [Hardware cache event] iTLB-load-misses [Hardware cache event] iTLB-loads [Hardware cache event] node-load-misses [Hardware cache event] node-loads [Hardware cache event] node-store-misses [Hardware cache event] node-stores [Hardware cache event] $ Reported-by: Brian Sweeney Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=153351 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index d9b80ef881cd..21fd573106ed 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -507,17 +507,17 @@ static int __perf_evsel__hw_cache_name(u64 config, char *bf, size_t size) u8 op, result, type = (config >> 0) & 0xff; const char *err = "unknown-ext-hardware-cache-type"; - if (type > PERF_COUNT_HW_CACHE_MAX) + if (type >= PERF_COUNT_HW_CACHE_MAX) goto out_err; op = (config >> 8) & 0xff; err = "unknown-ext-hardware-cache-op"; - if (op > PERF_COUNT_HW_CACHE_OP_MAX) + if (op >= PERF_COUNT_HW_CACHE_OP_MAX) goto out_err; result = (config >> 16) & 0xff; err = "unknown-ext-hardware-cache-result"; - if (result > PERF_COUNT_HW_CACHE_RESULT_MAX) + if (result >= PERF_COUNT_HW_CACHE_RESULT_MAX) goto out_err; err = "invalid-cache";