Opened 9 years ago
Closed 9 years ago
#5938 closed defect (fixed)
Segmentation fault when combining vsimem with vsigzip
| Reported by: | dsogari | Owned by: | warmerdam |
|---|---|---|---|
| Priority: | normal | Milestone: | |
| Component: | default | Version: | svn-trunk |
| Severity: | normal | Keywords: | segfault; vsimem; vsigzip |
| Cc: |
Description
Hi,
I found a problem with the VSIFCloseL function when using the memory filesystem driver in composition with the gzip driver. The problem is that if I open a gzip archive located under /vsimem, then "accidentally" delete the archive through /vsimem, and then try to close it, I get segmentation fault.
Looking at the code in VSIGZipFilesystemHandler::SaveInfo method I found that, at the end, it calls VSIGZipHandle::Duplicate to get a new handle. Only, it does not verify that the returned object is non NULL. So if it is, then the call to CloseBaseHandle produces segmentation fault.
Surely this is a very uncommon use case. Nonetheless, for the sake of robustness, I propose the following alteration.
in gdal/port/cpl_vsi_gzip.cpp [my local copy is in 28977]
method VSIGZipFilesystemHandler::SaveInfo, line 1327:
poHandleLastGZipFile->CloseBaseHandle();
replace by:
if (poHandleLastGZipFile)
poHandleLastGZipFile->CloseBaseHandle();
Please let me know if you find other issues with this solution.
Regards.
trunk r29033 "VSIGZipFilesystemHandler::SaveInfo_unlocked(): add check to avoid segfault in some rare circumstances (patch by dsogari, #5938)"