com php-src: fix possible array underflow: ext/standard/image.c

Commit: 5d9403f56c14fefafa558b7de45f132a4d3f5fde Author: Anatol Belski <ab@php.net> Fri, 19 Sep 2014 20:12:24 +0200 Parents: b8470e19e47bbab40c30d20f231ddd694c0ca669 Branches: PHP-5.5 PHP-5.6 master Link: http://git.php.net/?p=php-src.git;a=commitdiff;h=5d9403f56c14fefafa558b7de45f132a4d3f5fde Log: fix possible array underflow there are multiple issues with this code - php_stream_read() returns an unsigned val, so is >= 0 - if it read less than sizeof(a) bytes, the function operates on garbage - result->channels is an unsigned val, so >= 0 Changed paths: M ext/standard/image.c Diff: diff --git a/ext/standard/image.c b/ext/standard/image.c index 02246c6...f1910d2 100644 --- a/ext/standard/image.c +++ b/ext/standard/image.c @@ -365,8 +365,8 @@ static unsigned short php_read2(php_stream * stream TSRMLS_DC) { unsigned char a[2]; - /* just return 0 if we hit the end-of-file */ - if((php_stream_read(stream, a, sizeof(a))) <= 0) return 0; + /* return 0 if we couldn't read enough data */ + if((php_stream_read(stream, a, sizeof(a))) < sizeof(a)) return 0; return (((unsigned short)a[0]) << 8) + ((unsigned short)a[1]); } @@ -646,7 +646,7 @@ static struct gfxinfo *php_handle_jpc(php_stream * stream TSRMLS_DC) #endif result->channels = php_read2(stream TSRMLS_CC); /* Csiz */ - if (result->channels < 0 || result->channels > 256) { + if (result->channels == 0 && php_stream_eof(stream) || result->channels > 256) { efree(result); return NULL; }