UBIFS: use snprintf instead of sprintf when printing keys

Switch to 'snprintf()' which is more secure and reliable. This is also a
preparation to the subsequent key printing fixes.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index b09ba2d..6ae9fdc 100644 (file)
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -103,8 +103,8 @@ static const char *get_dent_type(int type)
        }
 }
 
-static void sprintf_key(const struct ubifs_info *c, const union ubifs_key *key,
-                       char *buffer)
+static void snprintf_key(const struct ubifs_info *c, const union ubifs_key *key,
+                        char *buffer, int len)
 {
        char *p = buffer;
        int type = key_type(c, key);
@@ -112,44 +112,46 @@ static void sprintf_key(const struct ubifs_info *c, const union ubifs_key *key,
        if (c->key_fmt == UBIFS_SIMPLE_KEY_FMT) {
                switch (type) {
                case UBIFS_INO_KEY:
-                       sprintf(p, "(%lu, %s)", (unsigned long)key_inum(c, key),
-                              get_key_type(type));
+                       len -= snprintf(p, len, "(%lu, %s)",
+                                       (unsigned long)key_inum(c, key),
+                                       get_key_type(type));
                        break;
                case UBIFS_DENT_KEY:
                case UBIFS_XENT_KEY:
-                       sprintf(p, "(%lu, %s, %#08x)",
-                               (unsigned long)key_inum(c, key),
-                               get_key_type(type), key_hash(c, key));
+                       len -= snprintf(p, len, "(%lu, %s, %#08x)",
+                                       (unsigned long)key_inum(c, key),
+                                       get_key_type(type), key_hash(c, key));
                        break;
                case UBIFS_DATA_KEY:
-                       sprintf(p, "(%lu, %s, %u)",
-                               (unsigned long)key_inum(c, key),
-                               get_key_type(type), key_block(c, key));
+                       len -= snprintf(p, len, "(%lu, %s, %u)",
+                                       (unsigned long)key_inum(c, key),
+                                       get_key_type(type), key_block(c, key));
                        break;
                case UBIFS_TRUN_KEY:
-                       sprintf(p, "(%lu, %s)",
-                               (unsigned long)key_inum(c, key),
-                               get_key_type(type));
+                       len -= snprintf(p, len, "(%lu, %s)",
+                                       (unsigned long)key_inum(c, key),
+                                       get_key_type(type));
                        break;
                default:
-                       sprintf(p, "(bad key type: %#08x, %#08x)",
-                               key->u32[0], key->u32[1]);
+                       len -= snprintf(p, len, "(bad key type: %#08x, %#08x)",
+                                       key->u32[0], key->u32[1]);
                }
        } else
-               sprintf(p, "bad key format %d", c->key_fmt);
+               len -= snprintf(p, len, "bad key format %d", c->key_fmt);
+       ubifs_assert(len > 0);
 }
 
 const char *dbg_key_str0(const struct ubifs_info *c, const union ubifs_key *key)
 {
        /* dbg_lock must be held */
-       sprintf_key(c, key, dbg_key_buf0);
+       snprintf_key(c, key, dbg_key_buf0, sizeof(dbg_key_buf0) - 1);
        return dbg_key_buf0;
 }
 
 const char *dbg_key_str1(const struct ubifs_info *c, const union ubifs_key *key)
 {
        /* dbg_lock must be held */
-       sprintf_key(c, key, dbg_key_buf1);
+       snprintf_key(c, key, dbg_key_buf1, sizeof(dbg_key_buf1) - 1);
        return dbg_key_buf1;
 }