[PATCH] hw/ufs: Fix buffer overflow bug

[Jeuk Kim]

It fixes the buffer overflow vulnerability in the ufs device.
The bug was detected by sanitizers.

You can reproduce it by:

cat << EOF |\
qemu-system-x86_64 \
-display none -machine accel=qtest -m 512M -M q35 -nodefaults -drive \
file=null-co://,if=none,id=disk0 -device ufs,id=ufs_bus -device \
ufs-lu,drive=disk0,bus=ufs_bus -qtest stdio
outl 0xcf8 0x80000810
outl 0xcfc 0xe0000000
outl 0xcf8 0x80000804
outw 0xcfc 0x06
write 0xe0000058 0x1 0xa7
write 0xa 0x1 0x50
EOF

Resolves: #2299
Fixes: 329f16624499 ("hw/ufs: Support for Query Transfer Requests")
Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>
---
 hw/ufs/ufs.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/ufs/ufs.c b/hw/ufs/ufs.c
index eccdb852a0..bac78a32bb 100644
--- a/hw/ufs/ufs.c
+++ b/hw/ufs/ufs.c
@@ -126,6 +126,10 @@ static MemTxResult ufs_dma_read_req_upiu(UfsRequest *req)
     copy_size = sizeof(UtpUpiuHeader) + UFS_TRANSACTION_SPECIFIC_FIELD_SIZE +
                 data_segment_length;
 
+    if (copy_size > sizeof(req->req_upiu)) {
+        copy_size = sizeof(req->req_upiu);
+    }
+
     ret = ufs_addr_read(u, req_upiu_base_addr, &req->req_upiu, copy_size);
     if (ret) {
         trace_ufs_err_dma_read_req_upiu(req->slot, req_upiu_base_addr);
@@ -225,6 +229,10 @@ static MemTxResult ufs_dma_write_rsp_upiu(UfsRequest *req)
         copy_size = rsp_upiu_byte_len;
     }
 
+    if (copy_size > sizeof(req->rsp_upiu)) {
+        copy_size = sizeof(req->rsp_upiu);
+    }
+
     ret = ufs_addr_write(u, rsp_upiu_base_addr, &req->rsp_upiu, copy_size);
     if (ret) {
         trace_ufs_err_dma_write_rsp_upiu(req->slot, rsp_upiu_base_addr);
-- 
2.34.1