[PATCH rdma-rc] RDMA/core: Don't infoleak GRH fields

[PATCH rdma-rc] RDMA/core: Don't infoleak GRH fields

[Leon Romanovsky]

From: Leon Romanovsky <leonro@nvidia.com>

If dst->is_global field is not set, the GRH fields are not cleared
and the following infoleak is reported.

=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
 instrument_copy_to_user include/linux/instrumented.h:121 [inline]
 _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
 copy_to_user include/linux/uaccess.h:209 [inline]
 ucma_init_qp_attr+0x8c7/0xb10 drivers/infiniband/core/ucma.c:1242
 ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732
 vfs_write+0x8ce/0x2030 fs/read_write.c:588
 ksys_write+0x28b/0x510 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __ia32_sys_write+0xdb/0x120 fs/read_write.c:652
 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
 __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable resp created at:
 ucma_init_qp_attr+0xa4/0xb10 drivers/infiniband/core/ucma.c:1214
 ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732

Bytes 40-59 of 144 are uninitialized
Memory access of size 144 starts at ffff888167523b00
Data copied to user address 0000000020000100

CPU: 1 PID: 25910 Comm: syz-executor.1 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================

Fixes: 4ba66093bdc6 ("IB/core: Check for global flag when using ah_attr")
Reported-by: syzbot+6d532fa8f9463da290bc@syzkaller.appspotmail.com
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/uverbs_marshall.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/uverbs_marshall.c b/drivers/infiniband/core/uverbs_marshall.c
index b8d715c68ca4..11a080646916 100644
--- a/drivers/infiniband/core/uverbs_marshall.c
+++ b/drivers/infiniband/core/uverbs_marshall.c
@@ -66,7 +66,7 @@ void ib_copy_ah_attr_to_user(struct ib_device *device,
 	struct rdma_ah_attr *src = ah_attr;
 	struct rdma_ah_attr conv_ah;
 
-	memset(&dst->grh.reserved, 0, sizeof(dst->grh.reserved));
+	memset(&dst->grh, 0, sizeof(dst->grh));
 
 	if ((ah_attr->type == RDMA_AH_ATTR_TYPE_OPA) &&
 	    (rdma_ah_get_dlid(ah_attr) > be16_to_cpu(IB_LID_PERMISSIVE)) &&
-- 
2.33.1

Re: [PATCH rdma-rc] RDMA/core: Don't infoleak GRH fields

[Jason Gunthorpe]

On Tue, Jan 04, 2022 at 02:21:52PM +0200, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> If dst->is_global field is not set, the GRH fields are not cleared
> and the following infoleak is reported.
> 
> =====================================================
> BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
>  instrument_copy_to_user include/linux/instrumented.h:121 [inline]
>  _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
>  copy_to_user include/linux/uaccess.h:209 [inline]
>  ucma_init_qp_attr+0x8c7/0xb10 drivers/infiniband/core/ucma.c:1242
>  ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732
>  vfs_write+0x8ce/0x2030 fs/read_write.c:588
>  ksys_write+0x28b/0x510 fs/read_write.c:643
>  __do_sys_write fs/read_write.c:655 [inline]
>  __se_sys_write fs/read_write.c:652 [inline]
>  __ia32_sys_write+0xdb/0x120 fs/read_write.c:652
>  do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
>  __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
>  do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
>  do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
>  entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> 
> Local variable resp created at:
>  ucma_init_qp_attr+0xa4/0xb10 drivers/infiniband/core/ucma.c:1214
>  ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732
> 
> Bytes 40-59 of 144 are uninitialized
> Memory access of size 144 starts at ffff888167523b00
> Data copied to user address 0000000020000100
> 
> CPU: 1 PID: 25910 Comm: syz-executor.1 Not tainted 5.16.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> =====================================================
> 
> Fixes: 4ba66093bdc6 ("IB/core: Check for global flag when using ah_attr")
> Reported-by: syzbot+6d532fa8f9463da290bc@syzkaller.appspotmail.com
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/core/uverbs_marshall.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied to for-rc, thanks

Jason