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Bug #78488 OOB in ZEND_FUNCTION(ffi_trampoline)
Submitted: 2019-09-03 13:45 UTC Modified: 2019-09-03 13:46 UTC
From: cmb@php.net Assigned: dmitry (profile)
Status: Closed Package: Unknown/Other Function
PHP Version: 7.4Git-2019-09-03 (Git) OS: Windows x86
Private report: No CVE-ID: None
 [2019-09-03 13:45 UTC] cmb@php.net
Description:
------------
As of commit 77a0fa1[1], x86 Windows debug builds signal stack
memory corruption in ZEND_FUNCTION(ffi_trampoline) when running
callconv.phpt.  The culprit is that we're allocating not enough
space[2], since FFI_SIZEOF_ARG is 4 on x86 Windows, but in
zend_ffi_pass_arg() we're copying doubles (and perhaps even wider
values) to that memory.

I'm somewhat confused to have a constant for the argument size,
since at least some call conventions do not have a fixed argument
size to my knowledge, but at least here we must not use this
constant, but rather the maximum size of the supported argument
types.

[1] <http://git.php.net/?p=php-src.git;a=commit;h=77a0fa101ed59f05ea07b03adb1cb66962fc45e7>
[2] <https://github.com/php/php-src/blob/php-7.4.0beta4/ext/ffi/ffi.c#L2616-L2617>


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 [2019-09-03 13:46 UTC] cmb@php.net
-Assigned To: +Assigned To: dmitry
 [2019-09-03 13:46 UTC] cmb@php.net
Dmitry, could you please have a look at this?
 [2019-09-04 09:17 UTC] dmitry@php.net
Automatic comment on behalf of dmitry@zend.com
Revision: http://git.php.net/?p=php-src.git;a=commit;h=1db0bad6a75eaaa6cc849767ace77dae63678bf4
Log: Fixed bug #78488 (OOB in ZEND_FUNCTION(ffi_trampoline)).
 [2019-09-04 09:17 UTC] dmitry@php.net
-Status: Assigned +Status: Closed
 [2019-09-04 09:17 UTC] dmitry@php.net
Automatic comment on behalf of dmitry@zend.com
Revision: http://git.php.net/?p=php-src.git;a=commit;h=d03d369fdbb45d87f97b31113c11d3e4c41404cd
Log: Fixed bug #78488 (OOB in ZEND_FUNCTION(ffi_trampoline)).
 
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