Re: [2/2] cxl: Fail mmap if requested mapping is larger than assigned problem state area

2015-07-08 Thread Michael Ellerman
On Tue, 2015-07-07 at 05:45:46 UTC, Ian Munsie wrote:
 From: Ian Munsie imun...@au1.ibm.com
 
 This patch makes the mmap call fail outright if the requested region is
 larger than the problem state area assigned to the context so the error
 is reported immediately rather than waiting for an attempt to access an
 address out of bounds.
 
 Although we never expect users to map more than the assigned problem
 state area and are not aware of anyone doing this (other than for
 testing), this does have the potential to break users if someone has
 used a larger range regardless. I'm submitting it for consideration, but
 if this change is not considered acceptable the previous patch is
 sufficient to prevent access out of bounds without breaking anyone.
 
 Signed-off-by: Ian Munsie imun...@au1.ibm.com

Applied to powerpc fixes, thanks.

https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/commit/?h=fixesid=5caaf5346892d1e7f0b8b7223062644f8538483f

cheers
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[PATCH 2/2] cxl: Fail mmap if requested mapping is larger than assigned problem state area

2015-07-06 Thread Ian Munsie
From: Ian Munsie imun...@au1.ibm.com

This patch makes the mmap call fail outright if the requested region is
larger than the problem state area assigned to the context so the error
is reported immediately rather than waiting for an attempt to access an
address out of bounds.

Although we never expect users to map more than the assigned problem
state area and are not aware of anyone doing this (other than for
testing), this does have the potential to break users if someone has
used a larger range regardless. I'm submitting it for consideration, but
if this change is not considered acceptable the previous patch is
sufficient to prevent access out of bounds without breaking anyone.

Signed-off-by: Ian Munsie imun...@au1.ibm.com
---
 drivers/misc/cxl/context.c | 10 +-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 6c1ce51..1287148 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -145,8 +145,16 @@ static const struct vm_operations_struct cxl_mmap_vmops = {
  */
 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
 {
+   u64 start = vma-vm_pgoff  PAGE_SHIFT;
u64 len = vma-vm_end - vma-vm_start;
-   len = min(len, ctx-psn_size);
+
+   if (ctx-afu-current_mode == CXL_MODE_DEDICATED) {
+   if (start + len  ctx-afu-adapter-ps_size)
+   return -EINVAL;
+   } else {
+   if (start + len  ctx-psn_size)
+   return -EINVAL;
+   }
 
if (ctx-afu-current_mode != CXL_MODE_DEDICATED) {
/* make sure there is a valid per process space for this AFU */
-- 
2.1.4

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