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[77.3.162.5]) by smtp.gmail.com with ESMTPSA id z17sm8884162eju.65.2021.05.10.03.56.50 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 May 2021 03:56:50 -0700 (PDT) From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= To: selinux@vger.kernel.org Subject: [PATCH 3/3] libselinux: do not use status page fallback mode internally Date: Mon, 10 May 2021 12:56:48 +0200 Message-Id: <20210510105648.14635-4-cgzones@googlemail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510105648.14635-1-cgzones@googlemail.com> References: <20210510105648.14635-1-cgzones@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Currently `avc_init_internal()`, called by `avc_open(3)` and `avc_init(3)`, does open the SELinux status page with fallback mode enabled. Quote from man:selinux_status_open(3): In this case, this function tries to open a netlink socket using .BR avc_netlink_open (3) and overwrite corresponding callbacks (setenforce and policyload). Thus, we need to pay attention to the interaction with these interfaces, when fallback mode is enabled. Calling `selinux_status_open` internally in fallback mode is bad, cause it overrides callbacks from client applications or the internal fallback-callbacks get overridden by client applications. Note that `avc_open(3)` gets called under the hood by `selinux_check_access(3)` without checking for failure. Also the status page is available since Linux 2.6.37, so failures of `selinux_status_open(3)` in non-fallback mode should only be caused by policies not allowing the client process to open/read/map the /sys/fs/selinux/status file. Signed-off-by: Christian Göttsche --- libselinux/src/avc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libselinux/src/avc.c b/libselinux/src/avc.c index 8314d7ba..daaedbc6 100644 --- a/libselinux/src/avc.c +++ b/libselinux/src/avc.c @@ -214,7 +214,7 @@ static int avc_init_internal(const char *prefix, avc_enforcing = rc; } - rc = selinux_status_open(1); + rc = selinux_status_open(0); if (rc < 0) { avc_log(SELINUX_ERROR, "%s: could not open selinux status page: %d (%s)\n", -- 2.31.1