| Message ID | 1579558202-26052-1-git-send-email-tyreld@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | aff8c8242bc638ba57247ae1ec5f272ac3ed3b92 |
| Headers | show |
| Series | powerpc/pseries/vio: Fix iommu_table use-after-free refcount warning | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (20862247a368dbb75d6e97d82345999adaacf3cc) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 8 lines checked |
| snowpatch_ozlabs/needsstable | warning | Please consider tagging this patch for stable! |
On 21/01/2020 09:10, Tyrel Datwyler wrote: > From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> > > Commit e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to > iommu_table") missed an iommu_table allocation in the pseries vio code. > The iommu_table is allocated with kzalloc and as a result the associated > kref gets a value of zero. This has the side effect that during a DLPAR > remove of the associated virtual IOA the iommu_tce_table_put() triggers > a use-after-free underflow warning. > > Call Trace: > [c0000002879e39f0] [c00000000071ecb4] refcount_warn_saturate+0x184/0x190 > (unreliable) > [c0000002879e3a50] [c0000000000500ac] iommu_tce_table_put+0x9c/0xb0 > [c0000002879e3a70] [c0000000000f54e4] vio_dev_release+0x34/0x70 > [c0000002879e3aa0] [c00000000087cfa4] device_release+0x54/0xf0 > [c0000002879e3b10] [c000000000d64c84] kobject_cleanup+0xa4/0x240 > [c0000002879e3b90] [c00000000087d358] put_device+0x28/0x40 > [c0000002879e3bb0] [c0000000007a328c] dlpar_remove_slot+0x15c/0x250 > [c0000002879e3c50] [c0000000007a348c] remove_slot_store+0xac/0xf0 > [c0000002879e3cd0] [c000000000d64220] kobj_attr_store+0x30/0x60 > [c0000002879e3cf0] [c0000000004ff13c] sysfs_kf_write+0x6c/0xa0 > [c0000002879e3d10] [c0000000004fde4c] kernfs_fop_write+0x18c/0x260 > [c0000002879e3d60] [c000000000410f3c] __vfs_write+0x3c/0x70 > [c0000002879e3d80] [c000000000415408] vfs_write+0xc8/0x250 > [c0000002879e3dd0] [c0000000004157dc] ksys_write+0x7c/0x120 > [c0000002879e3e20] [c00000000000b278] system_call+0x5c/0x68 > > Further, since the refcount was always zero the iommu_tce_table_put() > fails to call the iommu_table release function resulting in a leak. > > Fix this issue be initilizing the iommu_table kref immediately after > allocation. > > Fixes: e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table") > Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > arch/powerpc/platforms/pseries/vio.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c > index 79e2287..f682b7b 100644 > --- a/arch/powerpc/platforms/pseries/vio.c > +++ b/arch/powerpc/platforms/pseries/vio.c > @@ -1176,6 +1176,8 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev) > if (tbl == NULL) > return NULL; > > + kref_init(&tbl->it_kref); > + > of_parse_dma_window(dev->dev.of_node, dma_window, > &tbl->it_index, &offset, &size); > >
On Mon, 2020-01-20 at 22:10:02 UTC, Tyrel Datwyler wrote: > From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> > > Commit e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to > iommu_table") missed an iommu_table allocation in the pseries vio code. > The iommu_table is allocated with kzalloc and as a result the associated > kref gets a value of zero. This has the side effect that during a DLPAR > remove of the associated virtual IOA the iommu_tce_table_put() triggers > a use-after-free underflow warning. > > Call Trace: > [c0000002879e39f0] [c00000000071ecb4] refcount_warn_saturate+0x184/0x190 > (unreliable) > [c0000002879e3a50] [c0000000000500ac] iommu_tce_table_put+0x9c/0xb0 > [c0000002879e3a70] [c0000000000f54e4] vio_dev_release+0x34/0x70 > [c0000002879e3aa0] [c00000000087cfa4] device_release+0x54/0xf0 > [c0000002879e3b10] [c000000000d64c84] kobject_cleanup+0xa4/0x240 > [c0000002879e3b90] [c00000000087d358] put_device+0x28/0x40 > [c0000002879e3bb0] [c0000000007a328c] dlpar_remove_slot+0x15c/0x250 > [c0000002879e3c50] [c0000000007a348c] remove_slot_store+0xac/0xf0 > [c0000002879e3cd0] [c000000000d64220] kobj_attr_store+0x30/0x60 > [c0000002879e3cf0] [c0000000004ff13c] sysfs_kf_write+0x6c/0xa0 > [c0000002879e3d10] [c0000000004fde4c] kernfs_fop_write+0x18c/0x260 > [c0000002879e3d60] [c000000000410f3c] __vfs_write+0x3c/0x70 > [c0000002879e3d80] [c000000000415408] vfs_write+0xc8/0x250 > [c0000002879e3dd0] [c0000000004157dc] ksys_write+0x7c/0x120 > [c0000002879e3e20] [c00000000000b278] system_call+0x5c/0x68 > > Further, since the refcount was always zero the iommu_tce_table_put() > fails to call the iommu_table release function resulting in a leak. > > Fix this issue be initilizing the iommu_table kref immediately after > allocation. > > Fixes: e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table") > Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/aff8c8242bc638ba57247ae1ec5f272ac3ed3b92 cheers
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c index 79e2287..f682b7b 100644 --- a/arch/powerpc/platforms/pseries/vio.c +++ b/arch/powerpc/platforms/pseries/vio.c @@ -1176,6 +1176,8 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev) if (tbl == NULL) return NULL; + kref_init(&tbl->it_kref); + of_parse_dma_window(dev->dev.of_node, dma_window, &tbl->it_index, &offset, &size);