From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com ([192.55.52.88]:60800 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731185AbfAIPk0 (ORCPT ); Wed, 9 Jan 2019 10:40:26 -0500 From: Andy Shevchenko To: Alexander Viro , linux-fsdevel@vger.kernel.org, Andrew Morton , linux-kernel@vger.kernel.org, Kees Cook Cc: Andy Shevchenko Subject: [PATCH v1] seq_file: convert mangle_path() to use string_escape_str() Date: Wed, 9 Jan 2019 17:40:22 +0200 Message-Id: <20190109154022.23551-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Since string_escape_str() does not support overlapping buffer first we check if there is enough room in the buffer and then update a path. The side effect of this change is in case of failure the buffer is left unchanged. Signed-off-by: Andy Shevchenko --- fs/seq_file.c | 22 +++++++--------------- 1 file changed, 7 insertions(+), 15 deletions(-) diff --git a/fs/seq_file.c b/fs/seq_file.c index 1dea7a8a5255..b818b23070e6 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -421,21 +421,13 @@ EXPORT_SYMBOL(seq_printf); */ char *mangle_path(char *s, const char *p, const char *esc) { - while (s <= p) { - char c = *p++; - if (!c) { - return s; - } else if (!strchr(esc, c)) { - *s++ = c; - } else if (s + 4 > p) { - break; - } else { - *s++ = '\\'; - *s++ = '0' + ((c & 0300) >> 6); - *s++ = '0' + ((c & 070) >> 3); - *s++ = '0' + (c & 07); - } - } + size_t len = p + strlen(p) - s; + int ret; + + ret = string_escape_str(p, NULL, 0, ESCAPE_OCTAL, esc); + if (ret < len) + return s + string_escape_str(p, s, len, ESCAPE_OCTAL, esc); + return NULL; } EXPORT_SYMBOL(mangle_path); -- 2.20.1