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[52.70.167.183]) by smtp.gmail.com with ESMTPSA id u7sm5414249qkb.7.2020.06.04.13.08.41 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jun 2020 13:08:42 -0700 (PDT) From: Stephen Smalley To: selinux@vger.kernel.org Cc: Stephen Smalley Subject: [PATCH] libselinux: fix selinux_restorecon() statfs bug Date: Thu, 4 Jun 2020 16:08:31 -0400 Message-Id: <20200604200831.28866-1-stephen.smalley.work@gmail.com> X-Mailer: git-send-email 2.23.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org As reported in https://github.com/SELinuxProject/selinux/issues/248, setfiles -r (rootpath) fails when the alternate root contains a symlink that is correct relative to the alternate root but not in the current root. This is a regression introduced by commit e016502c0a26 ("libselinux: Save digest of all partial matches for directory"). Do not call statfs(2) here if acting on a symbolic link. Unfortunately there is no lstatfs() call. Ensure that we initialize the statfs buffer always. If the supplied file is a symlink, then we don't need to worry about the later tests of filesystem type because we wouldn't be setting the digest anyway and we are not performing a full sysfs relabel. While here, fix the earlier test for a directory to use the correct test. Reproducer: $ mkdir /root/my-chroot && echo foo > /root/my-chroot/link-target && ln -s /link-target /root/my-chroot/symlink $ echo "/root/my-chroot/symlink" | setfiles -vFi -r /root/my-chroot -f - /etc/selinux/targeted/contexts/files/file_contexts Before: setfiles: statfs(/root/my-chroot/symlink) failed: No such file or directory After: Relabeled /root/my-chroot/symlink from unconfined_u:object_r:admin_home_t:s0 to system_u:object_r:default_t:s0 Fixes: https://github.com/SELinuxProject/selinux/issues/248 Fixes: e016502c0a26 ("libselinux: Save digest of all partial matches for directory") Signed-off-by: Stephen Smalley --- libselinux/src/selinux_restorecon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/libselinux/src/selinux_restorecon.c b/libselinux/src/selinux_restorecon.c index 91dfeb66..d1ce830c 100644 --- a/libselinux/src/selinux_restorecon.c +++ b/libselinux/src/selinux_restorecon.c @@ -938,7 +938,7 @@ int selinux_restorecon(const char *pathname_orig, } /* Skip digest if not a directory */ - if ((sb.st_mode & S_IFDIR) != S_IFDIR) + if (!S_ISDIR(sb.st_mode)) setrestorecondigest = false; if (!flags.recurse) { @@ -952,7 +952,8 @@ int selinux_restorecon(const char *pathname_orig, } /* Obtain fs type */ - if (statfs(pathname, &sfsb) < 0) { + memset(&sfsb, 0, sizeof sfsb); + if (!S_ISLNK(sb.st_mode) && statfs(pathname, &sfsb) < 0) { selinux_log(SELINUX_ERROR, "statfs(%s) failed: %s\n", pathname, strerror(errno)); -- 2.23.3