From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Price Date: Mon, 9 Jul 2012 17:06:52 +0100 Subject: [Cluster-devel] [PATCH 2/2] fsck.gfs2: Fix buffer overflow in get_lockproto_table In-Reply-To: <1341850012-28904-1-git-send-email-anprice@redhat.com> References: <1341850012-28904-1-git-send-email-anprice@redhat.com> Message-ID: <1341850012-28904-2-git-send-email-anprice@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Coverity discovered a buffer overflow in this function where an overly long cluster name in cluster.conf could cause a crash while repairing the superblock. This patch fixes the bug by making sure the lock table is composed sensibly, limiting the fsname to 16 chars as documented, and only allowing the cluster name (which doesn't seem to have a documented max size) to use the remaining space in the locktable name string. Signed-off-by: Andrew Price --- gfs2/fsck/initialize.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) diff --git a/gfs2/fsck/initialize.c b/gfs2/fsck/initialize.c index f07e0b2..e56161e 100644 --- a/gfs2/fsck/initialize.c +++ b/gfs2/fsck/initialize.c @@ -753,12 +753,13 @@ static int init_system_inodes(struct gfs2_sbd *sdp) static int get_lockproto_table(struct gfs2_sbd *sdp) { FILE *fp; - char line[PATH_MAX], *p, *p2; - char fsname[PATH_MAX]; + char line[PATH_MAX]; + char *cluname, *end; + const char *fsname, *cfgfile = "/etc/cluster/cluster.conf"; memset(sdp->lockproto, 0, sizeof(sdp->lockproto)); memset(sdp->locktable, 0, sizeof(sdp->locktable)); - fp = fopen("/etc/cluster/cluster.conf", "rt"); + fp = fopen(cfgfile, "rt"); if (!fp) { /* no cluster.conf; must be a stand-alone file system */ strcpy(sdp->lockproto, "lock_nolock"); @@ -771,28 +772,29 @@ static int get_lockproto_table(struct gfs2_sbd *sdp) log_warn(_("Lock protocol assumed to be: " GFS2_DEFAULT_LOCKPROTO "\n")); strcpy(sdp->lockproto, GFS2_DEFAULT_LOCKPROTO); + while (fgets(line, sizeof(line) - 1, fp)) { - p = strstr(line,"locktable, p, p2 - p); + cluname = strstr(line,"locktable[0] == '\0') { - log_err(_("Error: Unable to determine cluster name from " - "/etc/cluster.conf\n")); + if (cluname == NULL || end == NULL || end - cluname < 1) { + log_err(_("Error: Unable to determine cluster name from %s\n"), + cfgfile); } else { - memset(fsname, 0, sizeof(fsname)); - p = strrchr(opts.device, '/'); - if (p) { - p++; - strncpy(fsname, p, sizeof(fsname)); - } else - strcpy(fsname, "repaired"); - strcat(sdp->locktable, ":"); - strcat(sdp->locktable, fsname); + fsname = strrchr(opts.device, '/'); + if (fsname) + fsname++; + else + fsname = "repaired"; + snprintf(sdp->locktable, sizeof(sdp->locktable), "%.*s:%.16s", + (int)(sizeof(sdp->locktable) - strlen(fsname) - 2), + cluname, fsname); log_warn(_("Lock table determined to be: %s\n"), sdp->locktable); } -- 1.7.10.4