From eb4b28178dcfea944b46c0dbb2923ce482a7bea8 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Wed, 13 Nov 2024 19:54:43 +0000
Subject: [PATCH] Fix GH-16780: gzseek aborts on non seekable stream.

the stream flags is set to non seekable, thus we bail out early
in the process.
---
 main/streams/streams.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/main/streams/streams.c b/main/streams/streams.c
index 4c66d8aadc39b..e560b9d17e438 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -1354,7 +1354,9 @@ PHPAPI int _php_stream_seek(php_stream *stream, zend_off_t offset, int whence)
 
 		switch(whence) {
 			case SEEK_CUR:
-				ZEND_ASSERT(stream->position >= 0);
+				if (UNEXPECTED(stream->position == -1)) {
+					goto fail;
+				}
 				if (UNEXPECTED(offset > ZEND_LONG_MAX - stream->position)) {
 					offset = ZEND_LONG_MAX;
 				} else {
@@ -1393,6 +1395,7 @@ PHPAPI int _php_stream_seek(php_stream *stream, zend_off_t offset, int whence)
 		return 0;
 	}
 
+fail:
 	php_error_docref(NULL, E_WARNING, "Stream does not support seeking");
 
 	return -1;