4.14-stable review patch. If anyone has any objections, please let me know.
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From: Michael J. Ruhl michael.j.ruhl@intel.com
commit 7709b0dc265f28695487712c45f02bbd1f98415d upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/infiniband/hw/hfi1/file_ops.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/infiniband/hw/hfi1/file_ops.c +++ b/drivers/infiniband/hw/hfi1/file_ops.c @@ -605,7 +605,7 @@ static int hfi1_file_mmap(struct file *f vmf = 1; break; case STATUS: - if (flags & (unsigned long)(VM_WRITE | VM_EXEC)) { + if (flags & VM_WRITE) { ret = -EPERM; goto done; }