From: Michael J. Ruhl michael.j.ruhl@intel.com
Applications that use the stack for execution purposes cause 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.
Because of this the EXECSTACK bit can be automatically set at link time for any application.
On application load, the ELF loader evaluates the EXECSTACK bit for the application and it's linked libraries. It will set the process VM flags to allow the stack to include the VM_EXEC bit if the EXECSTACK bit is set. This flag is propagated to the driver during the mmap() call in the vma flag bits.
Checking for this bit and failing the request with EPERM is overly conservative and will break any PSM application that has the bit set.
Remove the VM_EXEC flag from the check.
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 --- drivers/infiniband/hw/hfi1/file_ops.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c index 0ba0cf5..68c397a 100644 --- a/drivers/infiniband/hw/hfi1/file_ops.c +++ b/drivers/infiniband/hw/hfi1/file_ops.c @@ -488,7 +488,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_area_struct *vma) vmf = 1; break; case STATUS: - if (flags & (unsigned long)(VM_WRITE | VM_EXEC)) { + if (flags & VM_WRITE) { ret = -EPERM; goto done; }