Re: [PATCH-for-10.1 03/11] hw/sd/sdcard: Propagate response size to sd_response_r*_make()

[Richard Henderson]

On 8/1/25 07:27, Philippe Mathieu-Daudé wrote:

All sd_response_r*_make() fill the @response buffer. Now that
sd_do_command() knows the buffer size, propagate it to the
response fillers and assert for any overflow.

Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  hw/sd/sd.c | 40 ++++++++++++++++++++++++++++------------
  1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 1d88aee38d5..22bdb4ca3ab 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -729,34 +729,52 @@ static int sd_req_crc_validate(SDRequest *req)
      return sd_crc7(buffer, 5) != req->crc;  /* TODO */
  }

-static void sd_response_r1_make(SDState *sd, uint8_t *response)

+static size_t sd_response_r1_make(SDState *sd, uint8_t *response, size_t 
respsz)
  {
+    size_t rsplen = 4;
+
+    assert(respsz >= 4);
      stl_be_p(response, sd->card_status);

/* Clear the "clear on read" status bits */

      sd->card_status &= ~CARD_STATUS_C;
+
+    return rsplen;
  }

-static void sd_response_r3_make(SDState *sd, uint8_t *response)

+static size_t sd_response_r3_make(SDState *sd, uint8_t *response, size_t 
respsz)
  {
+    size_t rsplen = 4;
+
+    assert(respsz >= rsplen);
      stl_be_p(response, sd->ocr & ACMD41_R3_MASK);
+
+    return rsplen;
  }

-static void sd_response_r6_make(SDState *sd, uint8_t *response)

+static size_t sd_response_r6_make(SDState *sd, uint8_t *response, size_t 
respsz)
  {
      uint16_t status;

+ assert(respsz >= 4);

      status = ((sd->card_status >> 8) & 0xc000) |
               ((sd->card_status >> 6) & 0x2000) |
                (sd->card_status & 0x1fff);
      sd->card_status &= ~(CARD_STATUS_C & 0xc81fff);
      stw_be_p(response + 0, sd->rca);
      stw_be_p(response + 2, status);
+
+    return 4;
  }

-static void sd_response_r7_make(SDState *sd, uint8_t *response)

+static size_t sd_response_r7_make(SDState *sd, uint8_t *response, size_t 
respsz)
  {
+    size_t rsplen = 4;
+
+    assert(respsz >= rsplen);
      stl_be_p(response, sd->vhs);
+
+    return rsplen;
  }

static uint32_t sd_blk_len(SDState *sd)

@@ -2207,33 +2225,31 @@ send_response:
      switch (rtype) {
      case sd_r1:
      case sd_r1b:
-        sd_response_r1_make(sd, response);
-        rsplen = 4;
+        rsplen = sd_response_r1_make(sd, response, respsz);
          break;

case sd_r2_i:

+        assert(respsz >= 16);
          memcpy(response, sd->cid, sizeof(sd->cid));
          rsplen = 16;
          break;

case sd_r2_s:

+        assert(respsz >= 16);
          memcpy(response, sd->csd, sizeof(sd->csd));
          rsplen = 16;
          break;

case sd_r3:

-        sd_response_r3_make(sd, response);
-        rsplen = 4;
+        rsplen = sd_response_r3_make(sd, response, respsz);
          break;

case sd_r6:

-        sd_response_r6_make(sd, response);
-        rsplen = 4;
+        rsplen = sd_response_r6_make(sd, response, respsz);
          break;

case sd_r7:

-        sd_response_r7_make(sd, response);
-        rsplen = 4;
+        rsplen = sd_response_r7_make(sd, response, respsz);
          break;

case sd_r0:

I'm not keen on this, with constants and assertions scattered across 5 
functions.


r~