From cbd7bfc7fd99acdde58ec2b0bce990158fba1654 Mon Sep 17 00:00:00 2001 From: Athira Rajeev Date: Mon, 5 Sep 2022 19:49:29 +0530 Subject: tools/perf: Fix out of bound access to cpu mask array The cpu mask init code in "record__mmap_cpu_mask_init" function access "bits" array part of "struct mmap_cpu_mask". The size of this array is the value from cpu__max_cpu().cpu. This array is used to contain the cpumask value for each cpu. While setting bit for each cpu, it calls "set_bit" function which access index in "bits" array. If we provide a command line option to -C which is greater than the number of CPU's present in the system, the set_bit could access an array member which is out-of the array size. This is because currently, there is no boundary check for the CPU. This will result in seg fault: <<>> ./perf record -C 12341234 ls Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS Segmentation fault (core dumped) <<>> Debugging with gdb, points to function flow as below: <<>> set_bit record__mmap_cpu_mask_init record__init_thread_default_masks record__init_thread_masks cmd_record <<>> Fix this by adding boundary check for the array. After the patch: <<>> ./perf record -C 12341234 ls Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS Failed to initialize parallel data streaming masks <<>> With this fix, if -C is given a non-exsiting CPU, perf record will fail with: <<>> ./perf record -C 50 ls Failed to initialize parallel data streaming masks <<>> Reported-by: Nageswara R Sastry Signed-off-by: Athira Jajeev Tested-by: Arnaldo Carvalho de Melo Tested-by: Nageswara R Sastry Cc: Jiri Olsa Cc: Kajol Jain Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20220905141929.7171-2-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) (limited to 'tools') diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 4713f0f3a6cf..09b68d76bbdc 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -3358,16 +3358,22 @@ static struct option __record_options[] = { struct option *record_options = __record_options; -static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus) +static int record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus) { struct perf_cpu cpu; int idx; if (cpu_map__is_dummy(cpus)) - return; + return 0; - perf_cpu_map__for_each_cpu(cpu, idx, cpus) + perf_cpu_map__for_each_cpu(cpu, idx, cpus) { + /* Return ENODEV is input cpu is greater than max cpu */ + if ((unsigned long)cpu.cpu > mask->nbits) + return -ENODEV; set_bit(cpu.cpu, mask->bits); + } + + return 0; } static int record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, const char *mask_spec) @@ -3379,7 +3385,9 @@ static int record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, const cha return -ENOMEM; bitmap_zero(mask->bits, mask->nbits); - record__mmap_cpu_mask_init(mask, cpus); + if (record__mmap_cpu_mask_init(mask, cpus)) + return -ENODEV; + perf_cpu_map__put(cpus); return 0; @@ -3461,7 +3469,12 @@ static int record__init_thread_masks_spec(struct record *rec, struct perf_cpu_ma pr_err("Failed to allocate CPUs mask\n"); return ret; } - record__mmap_cpu_mask_init(&cpus_mask, cpus); + + ret = record__mmap_cpu_mask_init(&cpus_mask, cpus); + if (ret) { + pr_err("Failed to init cpu mask\n"); + goto out_free_cpu_mask; + } ret = record__thread_mask_alloc(&full_mask, cpu__max_cpu().cpu); if (ret) { @@ -3702,7 +3715,8 @@ static int record__init_thread_default_masks(struct record *rec, struct perf_cpu if (ret) return ret; - record__mmap_cpu_mask_init(&rec->thread_masks->maps, cpus); + if (record__mmap_cpu_mask_init(&rec->thread_masks->maps, cpus)) + return -ENODEV; rec->nr_threads = 1; -- cgit v1.2.3