Applications that use the stack for execution purposes cause userspace PSM
jobs to fail during mmap().
Both Fortran (non-standard format parsing) and C (callback functions
located in the stack) applications can be written such that stack
execution is required. The linker notes this via the gnu_stack ELF flag.
This causes READ_IMPLIES_EXEC to be set which forces all PROT_READ mmaps
to have PROT_EXEC for the process.
Checking for VM_EXEC bit and failing the request with EPERM is overly
conservative and will break any PSM application using executable stacks.
Cc: <stable@vger.kernel.org> #v4.14+
Fixes:
12220267645c ("IB/hfi: Protect against writable mmap")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
vmf = 1;
break;
case STATUS:
- if (flags & (unsigned long)(VM_WRITE | VM_EXEC)) {
+ if (flags & VM_WRITE) {
ret = -EPERM;
goto done;
}