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 A2D681B3F2D; Thu, 6 Jun 2024 14:17:14 +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=1717683434; cv=none; b=pOxXdarqf2rgVDHPuGda9/PSaXqM/2T0LmiLudXv8r0MjEwgeDlc0+bY1MFW9HVesO/Z9CTOL3HHMSQ9YuuiJsLAVmDKZaGKwKyDELfCgOEYVp5Ecm57KLoltJQEDIMN61/FEn7W7ms1r7xtG2mrStAqyXsHPa8I8GeN62g14T8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717683434; c=relaxed/simple; bh=HgO2mstBLzH3Xho2GCeUso8sYoKm7FKUNhbubfHGZu8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ze3OopnThfC6avX8VEnNdAuClqcNF9/ENCiH10WzFYmwj8tWY0B0JBbMnp4SKVEcK7lbhD9XmX96t2AIQcAEEd4dpSsnfi65TqkdmZ5IlbI6hPrRO6gpHLAkgnwtDiSd8ZaVNtd7bqj7pyKtVhsq+2jx18UbKjrwwu7KQSgL/Tc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0c9OJ9JM; 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="0c9OJ9JM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82330C2BD10; Thu, 6 Jun 2024 14:17:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1717683434; bh=HgO2mstBLzH3Xho2GCeUso8sYoKm7FKUNhbubfHGZu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0c9OJ9JMV+2CIUV9BQyUEBOc1RxC/LzHQvCBzoT6s5/CuLFYE9EpRQq8BMdNpO3/b HBHvIdZlookUAjHZZnEP0ChTZ2oh4/QaanISsTRNw5NMF74oUsQ23B/Yxs2u9bZoWs cFY3Ub+BdA8OJIVhYflx92gSYPwc6I1iE9dbUsOk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Beau Belgrave , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.6 379/744] tracing/user_events: Fix non-spaced field matching Date: Thu, 6 Jun 2024 16:00:51 +0200 Message-ID: <20240606131744.633741716@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240606131732.440653204@linuxfoundation.org> References: <20240606131732.440653204@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Beau Belgrave [ Upstream commit bd125a084091396f3e796bb3dc009940d9771811 ] When the ABI was updated to prevent same name w/different args, it missed an important corner case when fields don't end with a space. Typically, space is used for fields to help separate them, like "u8 field1; u8 field2". If no spaces are used, like "u8 field1;u8 field2", then the parsing works for the first time. However, the match check fails on a subsequent register, leading to confusion. This is because the match check uses argv_split() and assumes that all fields will be split upon the space. When spaces are used, we get back { "u8", "field1;" }, without spaces we get back { "u8", "field1;u8" }. This causes a mismatch, and the user program gets back -EADDRINUSE. Add a method to detect this case before calling argv_split(). If found force a space after the field separator character ';'. This ensures all cases work properly for matching. With this fix, the following are all treated as matching: u8 field1;u8 field2 u8 field1; u8 field2 u8 field1;\tu8 field2 u8 field1;\nu8 field2 Link: https://lore.kernel.org/linux-trace-kernel/20240423162338.292-2-beaub@linux.microsoft.com Fixes: ba470eebc2f6 ("tracing/user_events: Prevent same name but different args event") Signed-off-by: Beau Belgrave Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/trace_events_user.c | 76 +++++++++++++++++++++++++++++++- 1 file changed, 75 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index dda58681247e1..2461786b1e4d2 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1923,6 +1923,80 @@ static int user_event_trace_register(struct user_event *user) return ret; } +/* + * Counts how many ';' without a trailing space are in the args. + */ +static int count_semis_no_space(char *args) +{ + int count = 0; + + while ((args = strchr(args, ';'))) { + args++; + + if (!isspace(*args)) + count++; + } + + return count; +} + +/* + * Copies the arguments while ensuring all ';' have a trailing space. + */ +static char *insert_space_after_semis(char *args, int count) +{ + char *fixed, *pos; + int len; + + len = strlen(args) + count; + fixed = kmalloc(len + 1, GFP_KERNEL); + + if (!fixed) + return NULL; + + pos = fixed; + + /* Insert a space after ';' if there is no trailing space. */ + while (*args) { + *pos = *args++; + + if (*pos++ == ';' && !isspace(*args)) + *pos++ = ' '; + } + + *pos = '\0'; + + return fixed; +} + +static char **user_event_argv_split(char *args, int *argc) +{ + char **split; + char *fixed; + int count; + + /* Count how many ';' without a trailing space */ + count = count_semis_no_space(args); + + /* No fixup is required */ + if (!count) + return argv_split(GFP_KERNEL, args, argc); + + /* We must fixup 'field;field' to 'field; field' */ + fixed = insert_space_after_semis(args, count); + + if (!fixed) + return NULL; + + /* We do a normal split afterwards */ + split = argv_split(GFP_KERNEL, fixed, argc); + + /* We can free since argv_split makes a copy */ + kfree(fixed); + + return split; +} + /* * Parses the event name, arguments and flags then registers if successful. * The name buffer lifetime is owned by this method for success cases only. @@ -1946,7 +2020,7 @@ static int user_event_parse(struct user_event_group *group, char *name, return -EPERM; if (args) { - argv = argv_split(GFP_KERNEL, args, &argc); + argv = user_event_argv_split(args, &argc); if (!argv) return -ENOMEM; -- 2.43.0