linux-kernel - [RESEND PATCH v2] misc: fastrpc: fix improper packet size calculation

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Date:   Tue, 21 Sep 2021 17:03:01 +0530
From:   Jeya R <jeyr@...eaurora.org>
To:     linux-arm-msm@...r.kernel.org, srinivas.kandagatla@...aro.org
Cc:     Jeya R <jeyr@...eaurora.org>, gregkh@...uxfoundation.org,
        linux-kernel@...r.kernel.org, fastrpc.upstream@....qualcomm.com
Subject: [RESEND PATCH v2] misc: fastrpc: fix improper packet size calculation

The buffer list is sorted and this is not being considered while
calculating packet size. This would lead to improper copy length
calculation for non-dmaheap buffers which would eventually cause
sending improper buffers to DSP.

Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method")
Signed-off-by: Jeya R <jeyr@...eaurora.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>

Changes in v2:
- updated commit message to proper format
- added fixes tag to commit message
- removed unnecessary variable initialization
- removed length check during payload calculation
---
 drivers/misc/fastrpc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index beda610..69d45c4 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -719,16 +719,18 @@ static int fastrpc_get_meta_size(struct fastrpc_invoke_ctx *ctx)
 static u64 fastrpc_get_payload_size(struct fastrpc_invoke_ctx *ctx, int metalen)
 {
 	u64 size = 0;
-	int i;
+	int oix;
 
 	size = ALIGN(metalen, FASTRPC_ALIGN);
-	for (i = 0; i < ctx->nscalars; i++) {
+	for (oix = 0; oix < ctx->nbufs; oix++) {
+		int i = ctx->olaps[oix].raix;
+
 		if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1) {
 
-			if (ctx->olaps[i].offset == 0)
+			if (ctx->olaps[oix].offset == 0)
 				size = ALIGN(size, FASTRPC_ALIGN);
 
-			size += (ctx->olaps[i].mend - ctx->olaps[i].mstart);
+			size += (ctx->olaps[oix].mend - ctx->olaps[oix].mstart);
 		}
 	}
 
-- 
2.7.4