linux-kernel - [PATCH] iommu: fix KASAN use-after-free in iommu_insert_resv

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20191125103535.22782-1-eric.auger@redhat.com>
Date:   Mon, 25 Nov 2019 11:35:35 +0100
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com, joro@...tes.org,
        hch@....de, cai@....pw, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] iommu: fix KASAN use-after-free in iommu_insert_resv_region

Store the new region type in a variable. In case the new region
gets merged into another one, the new node is freed and nr shall
not be used anymore.

Fixes: 4dbd258ff63e ("iommu: Revisit iommu_insert_resv_region()
implementation")
Signed-off-by: Eric Auger <eric.auger@...hat.com>
Reported-by: Qian Cai <cai@....pw>
CC: Stable <stable@...r.kernel.org> #v5.3+
---
 drivers/iommu/iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index d658c7c6a2ab..338769f96d17 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -293,6 +293,8 @@ int iommu_insert_resv_region(struct iommu_resv_region *new,
 			     struct list_head *regions)
 {
 	struct iommu_resv_region *iter, *tmp, *nr, *top;
+	enum iommu_resv_type nr_type = new->type;
+
 	LIST_HEAD(stack);
 
 	nr = iommu_alloc_resv_region(new->start, new->length,
@@ -313,7 +315,7 @@ int iommu_insert_resv_region(struct iommu_resv_region *new,
 		phys_addr_t top_end, iter_end = iter->start + iter->length - 1;
 
 		/* no merge needed on elements of different types than @nr */
-		if (iter->type != nr->type) {
+		if (iter->type != nr_type) {
 			list_move_tail(&iter->list, &stack);
 			continue;
 		}
-- 
2.20.1