From de55f180e4c62efdeed956c0dda420b0d7026a39 Mon Sep 17 00:00:00 2001 From: German Gomez Date: Wed, 1 Dec 2021 12:33:29 +0000 Subject: [PATCH] perf tools: Prevent out-of-bounds access to registers The size of the cache of register values is arch-dependant (PERF_REGS_MAX). This has the potential of causing an out-of-bounds access in the function "perf_reg_value" if the local architecture contains less registers than the one the perf.data file was recorded on. Since the maximum number of registers is bound by the bitmask "u64 cache_mask", and the size of the cache when running under x86 systems is 64 already, fix the size to 64 and add a range-check to the function "perf_reg_value" to prevent out-of-bounds access. Reported-by: Alexandre Truong Reviewed-by: Kajol Jain Signed-off-by: German Gomez Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Cc: linux-csky@vger.kernel.org Cc: linux-riscv@lists.infradead.org Link: https://lore.kernel.org/r/20211201123334.679131-2-german.gomez@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.h | 5 ++++- tools/perf/util/perf_regs.c | 3 +++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h index 95ffed66369c3..c59331eea1d91 100644 --- a/tools/perf/util/event.h +++ b/tools/perf/util/event.h @@ -44,13 +44,16 @@ struct perf_event_attr; /* perf sample has 16 bits size limit */ #define PERF_SAMPLE_MAX_SIZE (1 << 16) +/* number of register is bound by the number of bits in regs_dump::mask (64) */ +#define PERF_SAMPLE_REGS_CACHE_SIZE (8 * sizeof(u64)) + struct regs_dump { u64 abi; u64 mask; u64 *regs; /* Cached values/mask filled by first register access. */ - u64 cache_regs[PERF_REGS_MAX]; + u64 cache_regs[PERF_SAMPLE_REGS_CACHE_SIZE]; u64 cache_mask; }; diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c index 5ee47ae1509c6..06a7461ba864c 100644 --- a/tools/perf/util/perf_regs.c +++ b/tools/perf/util/perf_regs.c @@ -25,6 +25,9 @@ int perf_reg_value(u64 *valp, struct regs_dump *regs, int id) int i, idx = 0; u64 mask = regs->mask; + if ((u64)id >= PERF_SAMPLE_REGS_CACHE_SIZE) + return -EINVAL; + if (regs->cache_mask & (1ULL << id)) goto out; -- 2.39.5