diff options
| author | Corinna Vinschen <corinna@vinschen.de> | 2015-08-25 23:15:22 +0300 |
|---|---|---|
| committer | Corinna Vinschen <corinna@vinschen.de> | 2015-08-25 23:15:22 +0300 |
| commit | 859c10beeeaaf1e0a1964118973aca1bc0460a51 (patch) | |
| tree | 650a7045a6a8542493122a9bc9733782a4e2cb1b | |
| parent | 70b02101ca6b5175c3e0b09757064f2aed8c3a35 (diff) | |
autload.cc: Avoid clobbering return address in noload on i686
This fixes a long-standing problem when GetProcAddress fails
to load a function. The noload code calls SetLastError on
i686 without saving the edx register. Starting with Windows 7,
SetLastError apparently uses $edx and the register is set to
0x00000000 on return. So the subsequent `jmp *$edx' in noload
supposed to return to the caller, actually jumps to address NULL,
which results in a SEGV.
* autoload.cc (noload): i686 only: Save and restore $edx when calling
SetLastError to avoid clobbering return address stating with Windows 7.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
| -rw-r--r-- | winsup/cygwin/ChangeLog | 5 | ||||
| -rw-r--r-- | winsup/cygwin/autoload.cc | 6 |
2 files changed, 9 insertions, 2 deletions
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index a23f835f8..c10d074f1 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,5 +1,10 @@ 2015-08-25 Corinna Vinschen <corinna@vinschen.de> + * autoload.cc (noload): i686 only: Save and restore $edx when calling + SetLastError to avoid clobbering return address stating with Windows 7. + +2015-08-25 Corinna Vinschen <corinna@vinschen.de> + * mmap.cc: Fix a few comments. 2015-08-24 Corinna Vinschen <corinna@vinschen.de> diff --git a/winsup/cygwin/autoload.cc b/winsup/cygwin/autoload.cc index 4299e3a21..8f9823b97 100644 --- a/winsup/cygwin/autoload.cc +++ b/winsup/cygwin/autoload.cc @@ -254,11 +254,13 @@ noload: \n\ addl %eax,%esp # Pop off bytes \n\ andl $0xffff0000,%eax# upper word \n\ subl %eax,%esp # adjust for possible return value \n\ - pushl %eax # Save for later \n\ + pushl %eax # Save return value for later \n\ + pushl %edx # Save return address for later \n\ movl $127,%eax # ERROR_PROC_NOT_FOUND \n\ pushl %eax # First argument \n\ call _SetLastError@4 # Set it \n\ - popl %eax # Get back argument \n\ + popl %edx # Get back return address \n\ + popl %eax # Get back return value \n\ sarl $16,%eax # return value in high order word \n\ jmp *%edx # Return \n\ 1: \n\ |