Patch "misc: fastrpc: Fix incorrect DMA mapping unmap request" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    misc: fastrpc: Fix incorrect DMA mapping unmap request

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     misc-fastrpc-fix-incorrect-dma-mapping-unmap-request.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 79cd4336559599c64b8386922036f8d5b86573e2
Author: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
Date:   Fri Aug 11 12:56:42 2023 +0100

    misc: fastrpc: Fix incorrect DMA mapping unmap request
    
    [ Upstream commit a2cb9cd6a3949a3804ad9fd7da234892ce6719ec ]
    
    Scatterlist table is obtained during map create request and the same
    table is used for DMA mapping unmap. In case there is any failure
    while getting the sg_table, ERR_PTR is returned instead of sg_table.
    
    When the map is getting freed, there is only a non-NULL check of
    sg_table which will also be true in case failure was returned instead
    of sg_table. This would result in improper unmap request. Add proper
    check before setting map table to avoid bad unmap request.
    
    Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method")
    Cc: stable <stable@xxxxxxxxxx>
    Signed-off-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
    Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230811115643.38578-3-srinivas.kandagatla@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index e9291694922bc..4c51d216f3d43 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -711,6 +711,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd,
 {
 	struct fastrpc_session_ctx *sess = fl->sctx;
 	struct fastrpc_map *map = NULL;
+	struct sg_table *table;
 	int err = 0;
 
 	if (!fastrpc_map_lookup(fl, fd, ppmap, true))
@@ -736,11 +737,12 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd,
 		goto attach_err;
 	}
 
-	map->table = dma_buf_map_attachment_unlocked(map->attach, DMA_BIDIRECTIONAL);
-	if (IS_ERR(map->table)) {
-		err = PTR_ERR(map->table);
+	table = dma_buf_map_attachment_unlocked(map->attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR(table)) {
+		err = PTR_ERR(table);
 		goto map_err;
 	}
+	map->table = table;
 
 	map->phys = sg_dma_address(map->table->sgl);
 	map->phys += ((u64)fl->sctx->sid << 32);