From 57fc032ad643ffd018d66bd4c1bd3a91de4841e8 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 30 Jul 2019 10:58:41 -0300 Subject: [PATCH] perf session: Avoid infinite loop when seeing invalid header.size Vince reported that when fuzzing the userland perf tool with a bogus perf.data file he got into a infinite loop in 'perf report'. Changing the return of fetch_mmaped_event() to ERR_PTR(-EINVAL) for that case gets us out of that infinite loop. Reported-by: Vince Weaver Tested-by: Vince Weaver Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/20190726211415.GE24867@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/session.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 11e6093c941b..b9fe71d11bf6 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include #include +#include #include #include #include @@ -1955,7 +1956,9 @@ fetch_mmaped_event(struct perf_session *session, /* We're not fetching the event so swap back again */ if (session->header.needs_swap) perf_event_header__bswap(&event->header); - return NULL; + pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx: fuzzed perf.data?\n", + __func__, head, event->header.size, mmap_size); + return ERR_PTR(-EINVAL); } return event; @@ -1973,6 +1976,9 @@ static int __perf_session__process_decomp_events(struct perf_session *session) while (decomp->head < decomp->size && !session_done()) { union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data); + if (IS_ERR(event)) + return PTR_ERR(event); + if (!event) break; @@ -2072,6 +2078,9 @@ remap: more: event = fetch_mmaped_event(session, head, mmap_size, buf); + if (IS_ERR(event)) + return PTR_ERR(event); + if (!event) { if (mmaps[map_idx]) { munmap(mmaps[map_idx], mmap_size);