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authorTrond Myklebust <Trond.Myklebust@netapp.com>2013-10-28 18:18:00 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2013-10-28 18:53:21 -0400
commit9d3a2260f0f4bd6379b0a0f131c743fff25b0029 (patch)
tree52e223ce02fc746865cac4bbce64b433fde53613 /net/sunrpc
parent5fccc5b52ee07d07a74ce53c6f174bff81e26a16 (diff)
downloadlinux-9d3a2260f0f4bd6379b0a0f131c743fff25b0029.tar.bz2
SUNRPC: Fix buffer overflow checking in gss_encode_v0_msg/gss_encode_v1_msg
In gss_encode_v1_msg, it is pointless to BUG() after the overflow has happened. Replace the existing sprintf()-based code with scnprintf(), and warn if an overflow is ever triggered. In gss_encode_v0_msg, replace the runtime BUG_ON() with an appropriate compile-time BUILD_BUG_ON. Reported-by: Bruce Fields <bfields@fieldses.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c56
1 files changed, 37 insertions, 19 deletions
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index cc24323d3045..97912b40c254 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -420,41 +420,53 @@ static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
memcpy(gss_msg->databuf, &uid, sizeof(uid));
gss_msg->msg.data = gss_msg->databuf;
gss_msg->msg.len = sizeof(uid);
- BUG_ON(sizeof(uid) > UPCALL_BUF_LEN);
+
+ BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
}
-static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
+static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
const char *service_name,
const char *target_name)
{
struct gss_api_mech *mech = gss_msg->auth->mech;
char *p = gss_msg->databuf;
- int len = 0;
-
- gss_msg->msg.len = sprintf(gss_msg->databuf, "mech=%s uid=%d ",
- mech->gm_name,
- from_kuid(&init_user_ns, gss_msg->uid));
- p += gss_msg->msg.len;
+ size_t buflen = sizeof(gss_msg->databuf);
+ int len;
+
+ len = scnprintf(p, buflen, "mech=%s uid=%d ", mech->gm_name,
+ from_kuid(&init_user_ns, gss_msg->uid));
+ buflen -= len;
+ p += len;
+ gss_msg->msg.len = len;
if (target_name) {
- len = sprintf(p, "target=%s ", target_name);
+ len = scnprintf(p, buflen, "target=%s ", target_name);
+ buflen -= len;
p += len;
gss_msg->msg.len += len;
}
if (service_name != NULL) {
- len = sprintf(p, "service=%s ", service_name);
+ len = scnprintf(p, buflen, "service=%s ", service_name);
+ buflen -= len;
p += len;
gss_msg->msg.len += len;
}
if (mech->gm_upcall_enctypes) {
- len = sprintf(p, "enctypes=%s ", mech->gm_upcall_enctypes);
+ len = scnprintf(p, buflen, "enctypes=%s ",
+ mech->gm_upcall_enctypes);
+ buflen -= len;
p += len;
gss_msg->msg.len += len;
}
- len = sprintf(p, "\n");
+ len = scnprintf(p, buflen, "\n");
+ if (len == 0)
+ goto out_overflow;
gss_msg->msg.len += len;
gss_msg->msg.data = gss_msg->databuf;
- BUG_ON(gss_msg->msg.len > UPCALL_BUF_LEN);
+ return 0;
+out_overflow:
+ WARN_ON_ONCE(1);
+ return -ENOMEM;
}
static struct gss_upcall_msg *
@@ -463,15 +475,15 @@ gss_alloc_msg(struct gss_auth *gss_auth,
{
struct gss_upcall_msg *gss_msg;
int vers;
+ int err = -ENOMEM;
gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
if (gss_msg == NULL)
- return ERR_PTR(-ENOMEM);
+ goto err;
vers = get_pipe_version(gss_auth->net);
- if (vers < 0) {
- kfree(gss_msg);
- return ERR_PTR(vers);
- }
+ err = vers;
+ if (err < 0)
+ goto err_free_msg;
gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
INIT_LIST_HEAD(&gss_msg->list);
rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
@@ -484,9 +496,15 @@ gss_alloc_msg(struct gss_auth *gss_auth,
gss_encode_v0_msg(gss_msg);
break;
default:
- gss_encode_v1_msg(gss_msg, service_name, gss_auth->target_name);
+ err = gss_encode_v1_msg(gss_msg, service_name, gss_auth->target_name);
+ if (err)
+ goto err_free_msg;
};
return gss_msg;
+err_free_msg:
+ kfree(gss_msg);
+err:
+ return ERR_PTR(err);
}
static struct gss_upcall_msg *