alpine 3.6
race weakness #1

5

Weakness Breakdown


Definition:

A race condition exists when parallel code accesses shared data without proper coordination. An attack that uses a race-condition weakness takes advantage of the unsafe data access to manipulate how one of the parallel sections of code reacts. Even though each process runs as intended, the outcome is unexpected. For example, consider a bank service that depends on an encryption key that it reads from a known location. An independent cryptography service is responsible for generating the key and placing it where the bank is expected to read it in a timely manner. If the bank and cryptography services do not coordinate with each other, then the bank may read a blank encryption key before cryptography writes the key to the location. This can effectively turn off all encryption for the bank without either service, or the administrator, knowing that something has gone wrong.

Warning code(s):

This accepts filename arguments; if an attacker can move those files, a race condition results..

File Name:

acl/src/acl-2.2.52/libacl/perm_copy_file.c

Context:

The highlighted line of code below is the trigger point of this particular Alpine 3.6 race weakness.

 			const char *qpath = quote (ctx, path);
			error (ctx, _("setting permissions for %s"), qpath);
			quote_free (ctx, qpath);
		}
	}
	(void) acl_free (acl);
	if (ret == 0 && S_ISDIR (mode)) {
# if defined(HAVE_ACL_DELETE_DEF_FILE)
		ret = acl_delete_def_file (path);
# else
		acl = acl_init (0);
		ret = acl_set_file (path, ACL_TYPE_DEFAULT, acl);
		(void) acl_free (acl);
# endif
		if (ret != 0) {
			const char *qpath = quote (ctx, path);
			error (ctx, _( "setting permissions for %s"), qpath);
			quote_free (ctx, qpath);
		}
	}
	return ret;
#endif

chmod_only:
	ret = chmod (path, mode);
	if (ret != 0) {
		const char *qpath = quote (ctx, path);
		error (ctx, _("setting permissions for %s"), qpath);
		quote_free (ctx, qpath);
	}
	return ret;
}

/* Copy the permissions of src_path to dst_path. This includes the
   file mode permission bits and ACLs. File ownership is not copied.
 */
int
perm_copy_file (const char *src_path, const char *dst_path,
		 struct error_context *ctx)
{
#if defined(HAVE_ACL_GET_FILE) && defined(HAVE_ACL_SET_FILE)
	acl_t acl;
#endif
	struct stat st;
	int ret = 0;

	ret = stat(src_path, &st);
	if (ret != 0) {
		const char *qpath = quote (ctx, src_path);
		error (ctx, "%s", qpath); 

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