Fix sscanf limits in pg_dump

danielgustafsson · danielgustafsson · commit abdf81a20ba2 · 2021-10-19T12:59:50.000+02:00
Make sure that the string parsing is limited by the size of the destination buffer. The buffer is bounded by MAXPGPATH, and thus the limit must be inserted via preprocessor expansion and the buffer increased by one to account for the terminator. There is no risk of overflow here, since in this case, the buffer scanned is smaller than the destination buffer. Backpatch all the way down to 9.6. Reviewed-by: Tom Lane Discussion: https://postgr.es/m/B14D3D7B-F98C-4E20-9459-C122C67647FB@yesql.se Backpatch-through: 9.6
diff --git a/src/bin/pg_dump/pg_backup_directory.c b/src/bin/pg_dump/pg_backup_directory.c
@@ -458,11 +458,11 @@ _LoadBlobs(ArchiveHandle *AH)
 	/* Read the blobs TOC file line-by-line, and process each blob */
 	while ((cfgets(ctx->blobsTocFH, line, MAXPGPATH)) != NULL)
 	{
-		char		fname[MAXPGPATH];
+		char		fname[MAXPGPATH + 1];
 		char		path[MAXPGPATH];
 
 		/* Can't overflow because line and fname are the same length. */
-		if (sscanf(line, "%u %s\n", &oid, fname) != 2)
+		if (sscanf(line, "%u %" CppAsString2(MAXPGPATH) "s\n", &oid, fname) != 2)
 			exit_horribly(modulename, "invalid line in large object TOC file \"%s\": \"%s\"\n",
 						  fname, line);
 
