diff options
| author | Shivaprasad G Bhat <sbhat@linux.ibm.com> | 2025-01-13 03:48:55 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-08 09:58:17 +0100 |
| commit | b853ff0b514c1df314246fcf94744005914b48cb (patch) | |
| tree | 5b89c27a34668b882a27f968e13369f09769807d | |
| parent | 6e601a64f7777e2f78c02db1a8b5ba3b7c5e9e31 (diff) | |
powerpc/pseries/iommu: Don't unset window if it was never set
commit 17391cb2613b82f8c405570fea605af3255ff8d2 upstream.
On pSeries, when user attempts to use the same vfio container used by
different iommu group, the spapr_tce_set_window() returns -EPERM
and the subsequent cleanup leads to the below crash.
Kernel attempted to read user page (308) - exploit attempt?
BUG: Kernel NULL pointer dereference on read at 0x00000308
Faulting instruction address: 0xc0000000001ce358
Oops: Kernel access of bad area, sig: 11 [#1]
NIP: c0000000001ce358 LR: c0000000001ce05c CTR: c00000000005add0
<snip>
NIP [c0000000001ce358] spapr_tce_unset_window+0x3b8/0x510
LR [c0000000001ce05c] spapr_tce_unset_window+0xbc/0x510
Call Trace:
spapr_tce_unset_window+0xbc/0x510 (unreliable)
tce_iommu_attach_group+0x24c/0x340 [vfio_iommu_spapr_tce]
vfio_container_attach_group+0xec/0x240 [vfio]
vfio_group_fops_unl_ioctl+0x548/0xb00 [vfio]
sys_ioctl+0x754/0x1580
system_call_exception+0x13c/0x330
system_call_vectored_common+0x15c/0x2ec
<snip>
--- interrupt: 3000
Fix this by having null check for the tbl passed to the
spapr_tce_unset_window().
Fixes: f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries")
Cc: stable@vger.kernel.org
Reported-by: Vaishnavi Bhat <vaish123@in.ibm.com>
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/173674009556.1559.12487885286848752833.stgit@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/powerpc/platforms/pseries/iommu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 29f1a0cc59cd..ae6f7a235d8b 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -2208,6 +2208,9 @@ static long spapr_tce_unset_window(struct iommu_table_group *table_group, int nu const char *win_name; int ret = -ENODEV; + if (!tbl) /* The table was never created OR window was never opened */ + return 0; + mutex_lock(&dma_win_init_mutex); if ((num == 0) && is_default_window_table(table_group, tbl)) |