From patchwork Thu Apr 17 22:30:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 14056270 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1CF571FBEA2; Thu, 17 Apr 2025 22:28:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744928906; cv=none; b=S8baYGCSHJmJsJkQ37URv1XF+ELnMQ4knNRrPOrR4LqQcwAzOSnQlk1wy9D8dVINpE1OksIrov9w+UB04IVu04KRKW+crFn4J7fBPZs3T1/XFuH+9GIWQJqmiX+hUEuC8s/jOQQyAz8/LxV/iD1tz4fuML3xaB3PzJ2dEU4TnOQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744928906; c=relaxed/simple; bh=LUxes0u84hfgI+/C68y4xKDFHbrXB3K7ZMDX8LMqB7Y=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=BDij/prZWlPV/fHrNuOdcbbvUrNLT/pn07NACoynzmJUCQuvcI+2fWlfkd4Iy/eQDpA0FzApDNA7GNlcd/SNKVK/ianJDrq1deQjVHdLzc9khqL8U4wT1Zep1+AXi0XQWx4bM+REjhUUNT0rybDdJ/W5psAxFhCGSSawfU3dCfo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFF04C4CEE4; Thu, 17 Apr 2025 22:28:23 +0000 (UTC) Date: Thu, 17 Apr 2025 18:30:03 -0400 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mathieu Desnoyers , Andrii Nakryiko , Mykyta Yatsenko , Andrew Morton Subject: [PATCH] tracing: Fix filter string testing Message-ID: <20250417183003.505835fb@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt The filter string testing uses strncpy_from_kernel/user_nofault() to retrieve the string to test the filter against. The if() statement was incorrect as it considered 0 as a fault, when it is only negative that it faulted. Link: https://lore.kernel.org/all/CAEf4BzbVPQ=BjWztmEwBPRKHUwNfKBkS3kce-Rzka6zvbQeVpg@mail.gmail.com/ Cc: stable@vger.kernel.org Fixes: 77360f9bbc7e5 ("tracing: Add test for user space strings when filtering on string pointers") Reported-by: Andrii Nakryiko Reported-by: Mykyta Yatsenko Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_filter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 0993dfc1c5c1..2048560264bb 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -808,7 +808,7 @@ static __always_inline char *test_string(char *str) kstr = ubuf->buffer; /* For safety, do not trust the string pointer */ - if (!strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE)) + if (strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE) < 0) return NULL; return kstr; } @@ -827,7 +827,7 @@ static __always_inline char *test_ustring(char *str) /* user space address? */ ustr = (char __user *)str; - if (!strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE)) + if (strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE) < 0) return NULL; return kstr;