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FAILED: patch "[PATCH] RDMA/i40iw: Address an mmap handler exploit in i40iw" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Nov 28, 2020

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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2ed381439e89fa6d1a0839ef45ccd45d99d8e915 Mon Sep 17 00:00:00 2001
From: Shiraz Saleem <[email protected]>
Date: Tue, 24 Nov 2020 18:56:16 -0600
Subject: [PATCH] RDMA/i40iw: Address an mmap handler exploit in i40iw

i40iw_mmap manipulates the vma->vm_pgoff to differentiate a push page mmap vs a doorbell mmap, and uses it to compute the pfn in remap_pfn_range without any validation. This is vulnerable to an mmap exploit as described
in: https://lore.kernel.org/r/[email protected]

The push feature is disabled in the driver currently and therefore no push mmaps are issued from user-space. The feature does not work as expected in the x722 product.

Remove the push module parameter and all VMA attribute manipulations for this feature in i40iw_mmap. Update i40iw_mmap to only allow DB user mmapings at offset = 0. Check vm_pgoff for zero and if the mmaps are bound to a single page.

Cc <[email protected]>
Fixes d37498417947 ("i40iw: add files for iwarp interface")
Link https://lore.kernel.org/r/[email protected] open here
Reported-by Di Zhu <[email protected]>
Signed-off-by Shiraz Saleem <[email protected]>
Signed-off-by Jason Gunthorpe <[email protected]>
drivers/infiniband/hw/i40iw/i40iw_main.c +0 -5
index 2408b279e4c2..584932d3cc44 100644
@@ -54,10 +54,6 @@
 #define DRV_VERSION	__stringify(DRV_VERSION_MAJOR) "."		\
 	__stringify(DRV_VERSION_MINOR) "." __stringify(DRV_VERSION_BUILD)
 
-static int push_mode;
-module_param(push_mode, int, 0644);
-MODULE_PARM_DESC(push_mode, "Low latency mode: 0=disabled (default), 1=enabled)");
-
 static int debug;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "debug flags: 0=disabled (default), 0x7fffffff=all");

@@ -1580,7 +1576,6 @@ static enum i40iw_status_code i40iw_setup_init_state(struct i40iw_handler *hdl,
 	if (status)
 		goto exit;
 	iwdev->obj_next = iwdev->obj_mem;
-	iwdev->push_mode = push_mode;
 
 	init_waitqueue_head(&iwdev->vchnl_waitq);
 	init_waitqueue_head(&dev->vf_reqs);
drivers/infiniband/hw/i40iw/i40iw_verbs.c +7 -30
index 581ecbadf586..533f3caecb7a 100644
@@ -167,39 +167,16 @@ static void i40iw_dealloc_ucontext(struct ib_ucontext *context)
  */
 static int i40iw_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
 {
-	struct i40iw_ucontext *ucontext;
-	u64 db_addr_offset, push_offset, pfn;
-
-	ucontext = to_ucontext(context);
-	if (ucontext->iwdev->sc_dev.is_pf) {
-		db_addr_offset = I40IW_DB_ADDR_OFFSET;
-		push_offset = I40IW_PUSH_OFFSET;
-		if (vma->vm_pgoff)
-			vma->vm_pgoff += I40IW_PF_FIRST_PUSH_PAGE_INDEX - 1;
-	} else {
-		db_addr_offset = I40IW_VF_DB_ADDR_OFFSET;
-		push_offset = I40IW_VF_PUSH_OFFSET;
-		if (vma->vm_pgoff)
-			vma->vm_pgoff += I40IW_VF_FIRST_PUSH_PAGE_INDEX - 1;
-	}
+	struct i40iw_ucontext *ucontext = to_ucontext(context);
+	u64 dbaddr;
 
-	vma->vm_pgoff += db_addr_offset >> PAGE_SHIFT;
-
-	if (vma->vm_pgoff == (db_addr_offset >> PAGE_SHIFT)) {
-		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-	} else {
-		if ((vma->vm_pgoff - (push_offset >> PAGE_SHIFT)) % 2)
-			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-		else
-			vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
-	}
+	if (vma->vm_pgoff || vma->vm_end - vma->vm_start != PAGE_SIZE)
+		return -EINVAL;
 
-	pfn = vma->vm_pgoff +
-	      (pci_resource_start(ucontext->iwdev->ldev->pcidev, 0) >>
-	       PAGE_SHIFT);
+	dbaddr = I40IW_DB_ADDR_OFFSET + pci_resource_start(ucontext->iwdev->ldev->pcidev, 0);
 
-	return rdma_user_mmap_io(context, vma, pfn, PAGE_SIZE,
-				 vma->vm_page_prot, NULL);
+	return rdma_user_mmap_io(context, vma, dbaddr >> PAGE_SHIFT, PAGE_SIZE,
+				 pgprot_noncached(vma->vm_page_prot), NULL);
 }
 
 /**