[MM] [PATCH] sim: validate IMSI value in +CIMI response

[Ben Chan <benchan chromium org>]

---
This patch is a stripped-down version of the previous patch "sim: retry SIM operations during initialization". It does not retry SIM operations but simply validates the IMSI value.

A follow-up patch is needed to handle retries appropriately under certain error conditions.

 src/mm-sim.c |   37 +++++++++++++++++++++++++++++++++++--
 1 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/mm-sim.c b/src/mm-sim.c
index 9cd31cc..b917361 100644
--- a/src/mm-sim.c
+++ b/src/mm-sim.c
@@ -1066,15 +1066,48 @@ load_sim_identifier (MMSim *self,
 /* IMSI */
 
 static gchar *
+parse_imsi (const gchar *response,
+            GError **error)
+{
+    const gchar *s;
+    int len;
+    gboolean success;
+
+    if (response) {
+        success = TRUE;
+        for (s = response, len = 0; *s; ++s, ++len) {
+            /* IMSI is a number with 15 or less decimal digits. */
+            if (!isdigit (*s) || len > 15) {
+                success = FALSE;
+                break;
+            }
+        }
+        if (success)
+            return g_strdup (response);
+    }
+
+    g_set_error (error,
+                 MM_CORE_ERROR,
+                 MM_CORE_ERROR_FAILED,
+                 "Invalid +CIMI response '%s'", response ? response : "<null>");
+    return NULL;
+}
+
+static gchar *
 load_imsi_finish (MMSim *self,
                   GAsyncResult *res,
                   GError **error)
 {
+    const gchar *result;
     gchar *imsi;
 
     if (g_simple_async_result_propagate_error (G_SIMPLE_ASYNC_RESULT (res), error))
         return NULL;
-    imsi = g_strdup (g_simple_async_result_get_op_res_gpointer (G_SIMPLE_ASYNC_RESULT (res)));
+    result = g_simple_async_result_get_op_res_gpointer (G_SIMPLE_ASYNC_RESULT (res));
+
+    imsi = parse_imsi (result, error);
+    if (!imsi)
+        return NULL;
 
     mm_dbg ("loaded IMSI: %s", imsi);
     return imsi;
@@ -1093,7 +1126,7 @@ load_imsi (MMSim *self,
         MM_BASE_MODEM (self->priv->modem),
         "+CIMI",
         3,
-        TRUE,
+        FALSE,
         (GAsyncReadyCallback)load_imsi_command_ready,
         g_simple_async_result_new (G_OBJECT (self),
                                    callback,
-- 
1.7.7.3