[PATCH v2 3/4] soc: qcom: geni-se: Fix fw_end computed before round-up; propagate size to caller

[Viken Dadhaniya]

fw_end was computed from the raw fw_size_in_items, before the odd-word
round-up. A segment with an odd word count could pass the bounds check
at the unrounded value but then be copied one word past the validated
limit. Move fw_end (and the cfg_{idx,val}_end) calculations to after
the round-up so they always reflect the true copy extent.

The caller geni_load_se_fw() re-read hdr->fw_size_in_items for the
memcpy_toio() length, bypassing the validated and rounded value
established by geni_find_protocol_fw(). Add a fw_size_out output
parameter and use it in the caller.

Fixes: d4bf06592ad6 ("soc: qcom: geni-se: Add support to load QUP SE Firmware via Linux subsystem")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Viken Dadhaniya <viken.dadhaniya@xxxxxxxxxxxxxxxx>
---
 drivers/soc/qcom/qcom-geni-se.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 54c0a66d6dd6..11ca8223fbcd 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -1230,6 +1230,8 @@ EXPORT_SYMBOL_GPL(geni_se_resources_init);
  * @se: Pointer to the serial engine structure.
  * @fw: Pointer to the firmware image.
  * @protocol: Expected serial engine protocol type.
+ * @fw_size_out: Non-NULL output parameter; receives the rounded, validated
+ *               firmware word count on success.
  *
  * Identifies the appropriate firmware image or configuration required for a
  * specific communication protocol instance running on a Qualcomm GENI
@@ -1239,7 +1241,8 @@ EXPORT_SYMBOL_GPL(geni_se_resources_init);
  * Return: pointer to a valid 'struct se_fw_hdr' if found, or NULL otherwise.
  */
 static struct se_fw_hdr *geni_find_protocol_fw(struct geni_se *se, const struct firmware *fw,
-					       enum geni_se_protocol_type protocol)
+					       enum geni_se_protocol_type protocol,
+					       u32 *fw_size_out)
 {
 	struct device *dev = se->dev;
 	const struct elf32_hdr *ehdr;
@@ -1289,11 +1292,6 @@ static struct se_fw_hdr *geni_find_protocol_fw(struct geni_se *se, const struct
 
 		sefw = (struct se_fw_hdr *)(fw->data + phdr->p_offset);
 		fw_size = le16_to_cpu(sefw->fw_size_in_items);
-		fw_end = le16_to_cpu(sefw->fw_offset) + fw_size * sizeof(u32);
-		cfg_idx_end = le16_to_cpu(sefw->cfg_idx_offset) +
-			      le16_to_cpu(sefw->cfg_size_in_items) * sizeof(u8);
-		cfg_val_end = le16_to_cpu(sefw->cfg_val_offset) +
-			      le16_to_cpu(sefw->cfg_size_in_items) * sizeof(u32);
 
 		if (le32_to_cpu(sefw->magic) != SE_MAGIC_NUM || le32_to_cpu(sefw->version) != 1)
 			continue;
@@ -1306,6 +1304,12 @@ static struct se_fw_hdr *geni_find_protocol_fw(struct geni_se *se, const struct
 			sefw->fw_size_in_items = cpu_to_le16(fw_size);
 		}
 
+		fw_end = le16_to_cpu(sefw->fw_offset) + fw_size * sizeof(u32);
+		cfg_idx_end = le16_to_cpu(sefw->cfg_idx_offset) +
+			      le16_to_cpu(sefw->cfg_size_in_items) * sizeof(u8);
+		cfg_val_end = le16_to_cpu(sefw->cfg_val_offset) +
+			      le16_to_cpu(sefw->cfg_size_in_items) * sizeof(u32);
+
 		prog_ram_depth = FIELD_GET(PROG_RAM_DEPTH_MSK,
 					   readl_relaxed(se->base + SE_HW_PARAM_2));
 		if (fw_size >= prog_ram_depth) {
@@ -1320,6 +1324,7 @@ static struct se_fw_hdr *geni_find_protocol_fw(struct geni_se *se, const struct
 			continue;
 		}
 
+		*fw_size_out = fw_size;
 		return sefw;
 	}
 
@@ -1430,11 +1435,11 @@ static int geni_load_se_fw(struct geni_se *se, const struct firmware *fw,
 {
 	const u32 *fw_data, *cfg_val_arr;
 	const u8 *cfg_idx_arr;
-	u32 i, reg_value;
+	u32 i, reg_value, fw_size_in_items;
 	int ret;
 	struct se_fw_hdr *hdr;
 
-	hdr = geni_find_protocol_fw(se, fw, protocol);
+	hdr = geni_find_protocol_fw(se, fw, protocol, &fw_size_in_items);
 	if (!hdr)
 		return -EINVAL;
 
@@ -1511,7 +1516,7 @@ static int geni_load_se_fw(struct geni_se *se, const struct firmware *fw,
 
 	/* Program RAM address space. */
 	memcpy_toio(se->base + SE_GENI_CFG_RAMN, fw_data,
-		    le16_to_cpu(hdr->fw_size_in_items) * sizeof(u32));
+		    fw_size_in_items * sizeof(u32));
 
 	/* Put default values on GENI's output pads. */
 	writel_relaxed(0x1, se->base + GENI_FORCE_DEFAULT_REG);

-- 
2.34.1