From: Matan Barak Date: Thu, 14 Apr 2016 13:52:10 +0000 (+0300) Subject: IB/mlx5: Allow mapping the free running counter on PROT_EXEC X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6cbac1e4cd0e0110b4be38c201fc055249dfd365;p=linux-beck.git IB/mlx5: Allow mapping the free running counter on PROT_EXEC The current mlx5 code disallows mapping the free running counter of mlx5 based hardwares when PROT_EXEC is set. Although this behaviour is correct, Linux does add an implicit VM_EXEC to the vm_flags if the READ_IMPLIES_EXEC bit is set in the process personality. This happens for example if the process stack is executable. This causes libmlx5 to output a warning and prevents the user from reading the free running clock. Executing the init segment of the hardware isn't a security risk (at least no more than executing a process own stack), so we just prevent writes to there. Fixes: d69e3bcf7976 ('IB/mlx5: Mmap the HCA's core clock register to user-space') Signed-off-by: Matan Barak Reviewed-by: Haggai Eran Signed-off-by: Doug Ledford --- diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index 6ad0489cb3c5..f2a1ad9b1a7a 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1108,7 +1108,7 @@ static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vm if (vma->vm_end - vma->vm_start != PAGE_SIZE) return -EINVAL; - if (vma->vm_flags & (VM_WRITE | VM_EXEC)) + if (vma->vm_flags & VM_WRITE) return -EPERM; /* Don't expose to user-space information it shouldn't have */