From mboxrd@z Thu Jan 1 00:00:00 1970 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 5345328B4E4; Wed, 23 Apr 2025 15:33:13 +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=1745422396; cv=none; b=E7SkajuE2fp2Q4Bm64wSer8Of9PusEh4Xy5Twa+wn3ab3Xr4l2djqHkUrZ3ALRaXwacN9R2k+L153/YXwRZxqsVJArUtNfUl4/PDy53IwFdma5u4bOYrKZreLfvYE0T5YcG5UdFmZAf87DMz/CS9lovfTJrkRQ6tf3208ZRew0c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745422396; c=relaxed/simple; bh=qFCdy2tDQBg0QOrwlgOGnIC2pDtXzKkTV9VAlNUSu6A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HvcvOCWVd7Vw0gH+J7WspLahbplCAQF1USflDqJhIfw3UPksNYa/lXDTyqqVqMuqT7j2Q+IRc0eXVNhldHeWeWC43uEE7mxSAwAPT7h2cfG12EqZPBN6xfw4WIApWllesaufnHskgc5nN5PIWRf0LdxEVPlJq/ttOGDIh1lBNFA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nGfAY2CD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nGfAY2CD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75387C4CEE2; Wed, 23 Apr 2025 15:33:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745422393; bh=qFCdy2tDQBg0QOrwlgOGnIC2pDtXzKkTV9VAlNUSu6A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nGfAY2CD3OWejkKgeA8luoUoK9YVQ3pNS3yHYnH89x4utU+K/s2TO6ioq4jJNVsW5 CFl+I+ngyTO8JjuJK5O3XKmJCBzr5FYETascWYl+c/w3/KrHAgep9boeTm/aW79W0B 3JsT/Uz5AQIu3/cMqLnNENi69Xf6c3YpL4jdSFQ4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton , Andrii Nakryiko , Mykyta Yatsenko , "Steven Rostedt (Google)" Subject: [PATCH 6.6 334/393] tracing: Fix filter string testing Date: Wed, 23 Apr 2025 16:43:50 +0200 Message-ID: <20250423142657.134025077@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250423142643.246005366@linuxfoundation.org> References: <20250423142643.246005366@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt commit a8c5b0ed89a3f2c81c6ae0b041394e6eea0e7024 upstream. 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. Running the following commands: # cd /sys/kernel/tracing # echo "filename.ustring ~ \"/proc*\"" > events/syscalls/sys_enter_openat/filter # echo 1 > events/syscalls/sys_enter_openat/enable # ls /proc/$$/maps # cat trace Would produce nothing, but with the fix it will produce something like: ls-1192 [007] ..... 8169.828333: sys_openat(dfd: ffffffffffffff9c, filename: 7efc18359904, flags: 80000, mode: 0) Link: https://lore.kernel.org/all/CAEf4BzbVPQ=BjWztmEwBPRKHUwNfKBkS3kce-Rzka6zvbQeVpg@mail.gmail.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Andrew Morton Link: https://lore.kernel.org/20250417183003.505835fb@gandalf.local.home 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) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_filter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -808,7 +808,7 @@ static __always_inline char *test_string 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_ustrin /* 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;