From: Andre Noll <maan@tuebingen.mpg.de>
Date: Wed, 5 Sep 2018 10:13:35 +0000 (+0200)
Subject: blob: Avoid direct access to blob IDs.
X-Git-Tag: v0.6.3~63^2
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=126b6744c6dc58160dcbcc05e2aff2be7147f02f

blob: Avoid direct access to blob IDs.

Some places of blob.c use read_u32() to get the blob ID from the
osl object while others directly access the mapped memory through
a uint32_t pointer. Besides alignment issues, this causes trouble
on big endian machines. Make sure we always use the primitives from
portable_io.h.
---

diff --git a/blob.c b/blob.c
index e10b522f..4ecbc45b 100644
--- a/blob.c
+++ b/blob.c
@@ -103,7 +103,7 @@ static int print_blob(struct osl_table *table, struct osl_row *row,
 		para_printf(&aca->pbout, "cannot list %s\n", name);
 		return ret;
 	}
-	id = *(uint32_t *)obj.data;
+	id = read_u32(obj.data);
 	para_printf(&aca->pbout, "%u\t%s\n", id, name);
 	return 1;
 }
@@ -266,7 +266,8 @@ static int com_addblob_callback(__a_unused const struct lls_command * const cmd,
 	struct osl_object objs[NUM_BLOB_COLUMNS];
 	char *name = aca->query.data;
 	size_t name_len = strlen(name) + 1;
-	uint32_t id;
+	uint32_t id = (uint32_t)-1; /* STFU, gcc */
+	char id_buf[sizeof(id)];
 	unsigned num_rows;
 	int ret;
 
@@ -274,10 +275,15 @@ static int com_addblob_callback(__a_unused const struct lls_command * const cmd,
 	if (ret < 0)
 		goto out;
 	if (!num_rows) { /* this is the first entry ever added */
-		/* insert dummy row containing the id */
-		id = 2; /* this entry will be entry #1, so 2 is the next */
-		objs[BLOBCOL_ID].data = &id;
-		objs[BLOBCOL_ID].size = sizeof(id);
+		/*
+		 * Insert dummy row containing the next free ID. Since we are
+		 * about to insert the first blob with ID 1, the next free ID
+		 * will be 2.
+		 */
+		id = 2U;
+		write_u32(id_buf, id);
+		objs[BLOBCOL_ID].data = id_buf;
+		objs[BLOBCOL_ID].size = sizeof(id_buf);
 		objs[BLOBCOL_NAME].data = "";
 		objs[BLOBCOL_NAME].size = 1;
 		objs[BLOBCOL_DEF].data = "";
@@ -296,7 +302,7 @@ static int com_addblob_callback(__a_unused const struct lls_command * const cmd,
 			ret = osl(osl_get_object(table, row, BLOBCOL_ID, &obj));
 			if (ret < 0)
 				goto out;
-			id = *(uint32_t *)obj.data;
+			id = read_u32(obj.data);
 			obj.data = name + name_len;
 			obj.size = aca->query.size - name_len;
 			ret = osl(osl_update_object(table, row, BLOBCOL_DEF, &obj));
@@ -311,15 +317,17 @@ static int com_addblob_callback(__a_unused const struct lls_command * const cmd,
 		ret = osl(osl_get_object(table, row, BLOBCOL_ID, &obj));
 		if (ret < 0)
 			goto out;
-		id = *(uint32_t *)obj.data + 1;
-		obj.data = &id;
+		id = read_u32(obj.data) + 1;
+		write_u32(id_buf, id);
+		obj.data = &id_buf;
 		ret = osl(osl_update_object(table, row, BLOBCOL_ID, &obj));
 		if (ret < 0)
 			goto out;
 	}
 	id--;
-	objs[BLOBCOL_ID].data = &id;
-	objs[BLOBCOL_ID].size = sizeof(id);
+	write_u32(id_buf, id);
+	objs[BLOBCOL_ID].data = &id_buf;
+	objs[BLOBCOL_ID].size = sizeof(id_buf);
 	objs[BLOBCOL_NAME].data = name;
 	objs[BLOBCOL_NAME].size = name_len;
 	objs[BLOBCOL_DEF].data = name + name_len;