[PATCH-for-9.1? v2 4/4] hw/sd/sdhci: Check ADMA descriptors can be accessed

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Since malicious guest can write invalid addresses to
the ADMASYSADDR register, we need to check whether the
descriptor could be correctly filled or not.

Cc: qemu-stable@nongnu.org
Fixes: d7dfca0807 ("hw/sdhci: introduce standard SD host controller")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/sd/sdhci.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index 2d8fa3151a..6794ee2267 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -701,13 +701,18 @@ static void trace_adma_description(const char *type, const ADMADescr *dscr)
 static void get_adma_description(SDHCIState *s, ADMADescr *dscr)
 {
     hwaddr entry_addr = (hwaddr)s->admasysaddr;
+    MemTxResult res;
+
     switch (SDHC_DMA_TYPE(s->hostctl1)) {
     case SDHC_CTRL_ADMA2_32:
         {
             uint64_t adma2 = 0;
 
-            dma_memory_read(s->dma_as, entry_addr, &adma2, sizeof(adma2),
-                            MEMTXATTRS_UNSPECIFIED);
+            res = dma_memory_read(s->dma_as, entry_addr, &adma2, sizeof(adma2),
+                                  MEMTXATTRS_UNSPECIFIED);
+            if (res != MEMTX_OK) {
+                break;
+            }
             adma2 = le64_to_cpu(adma2);
             /*
              * The spec does not specify endianness of descriptor table.
@@ -724,8 +729,11 @@ static void get_adma_description(SDHCIState *s, ADMADescr *dscr)
         {
             uint32_t adma1 = 0;
 
-            dma_memory_read(s->dma_as, entry_addr, &adma1, sizeof(adma1),
-                            MEMTXATTRS_UNSPECIFIED);
+            res = dma_memory_read(s->dma_as, entry_addr, &adma1, sizeof(adma1),
+                                  MEMTXATTRS_UNSPECIFIED);
+            if (res != MEMTX_OK) {
+                break;
+            }
             adma1 = le32_to_cpu(adma1);
             dscr->addr = (hwaddr)(adma1 & ~0xfff);
             dscr->attr = (uint8_t)extract32(adma1, 0, 7);
@@ -748,8 +756,11 @@ static void get_adma_description(SDHCIState *s, ADMADescr *dscr)
             } QEMU_PACKED adma2;
             QEMU_BUILD_BUG_ON(sizeof(adma2) != 12);
 
-            dma_memory_read(s->dma_as, entry_addr, &adma2, sizeof(adma2),
-                            MEMTXATTRS_UNSPECIFIED);
+            res = dma_memory_read(s->dma_as, entry_addr, &adma2, sizeof(adma2),
+                                  MEMTXATTRS_UNSPECIFIED);
+            if (res != MEMTX_OK) {
+                break;
+            }
             dscr->length = le16_to_cpu(adma2.length);
             dscr->addr = le64_to_cpu(adma2.addr);
             dscr->attr = adma2.attr & (uint8_t) ~0xc0;
-- 
2.45.2