65 lines
2.3 KiB
Diff
65 lines
2.3 KiB
Diff
From 70303420b5721c38998cf987e6b7d30cc62d4ff1 Mon Sep 17 00:00:00 2001
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From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
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Date: Thu, 21 Jun 2018 13:20:53 -0400
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Subject: [PATCH] tracing: Check for no filter when processing event filters
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The syzkaller detected a out-of-bounds issue with the events filter code,
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specifically here:
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prog[N].pred = NULL; /* #13 */
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prog[N].target = 1; /* TRUE */
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prog[N+1].pred = NULL;
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prog[N+1].target = 0; /* FALSE */
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-> prog[N-1].target = N;
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prog[N-1].when_to_branch = false;
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As that's the first reference to a "N-1" index, it appears that the code got
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here with N = 0, which means the filter parser found no filter to parse
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(which shouldn't ever happen, but apparently it did).
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Add a new error to the parsing code that will check to make sure that N is
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not zero before going into this part of the code. If N = 0, then -EINVAL is
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returned, and a error message is added to the filter.
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Cc: stable@vger.kernel.org
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Fixes: 80765597bc587 ("tracing: Rewrite filter logic to be simpler and faster")
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Reported-by: air icy <icytxw@gmail.com>
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bugzilla url: https://bugzilla.kernel.org/show_bug.cgi?id=200019
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Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Signed-off-by: Jeremy Cline <jcline@redhat.com>
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---
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kernel/trace/trace_events_filter.c | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
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index e1c818dbc0d7..0dceb77d1d42 100644
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--- a/kernel/trace/trace_events_filter.c
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+++ b/kernel/trace/trace_events_filter.c
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@@ -78,7 +78,8 @@ static const char * ops[] = { OPS };
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C(TOO_MANY_PREDS, "Too many terms in predicate expression"), \
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C(INVALID_FILTER, "Meaningless filter expression"), \
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C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
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- C(INVALID_VALUE, "Invalid value (did you forget quotes)?"),
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+ C(INVALID_VALUE, "Invalid value (did you forget quotes)?"), \
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+ C(NO_FILTER, "No filter found"),
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#undef C
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#define C(a, b) FILT_ERR_##a
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@@ -550,6 +551,13 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
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goto out_free;
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}
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+ if (!N) {
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+ /* No program? */
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+ ret = -EINVAL;
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+ parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
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+ goto out_free;
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+ }
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+
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prog[N].pred = NULL; /* #13 */
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prog[N].target = 1; /* TRUE */
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prog[N+1].pred = NULL;
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--
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2.17.1
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