Messages in this thread Patch in this message | | | From | Srinivas Kandagatla <> | Subject | [PATCH 2/3] misc: fastrpc: Don't remove map on creater_process and device_release | Date | Thu, 24 Nov 2022 17:49:40 +0000 |
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From: Abel Vesa <abel.vesa@linaro.org>
Do not remove the map from the list on error path in fastrpc_init_create_process, instead call fastrpc_map_put, to avoid use-after-free. Do not remove it on fastrpc_device_release either, call fastrpc_map_put instead.
The fastrpc_free_map is the only proper place to remove the map. This is called only after the reference count is 0.
Fixes: b49f6d83e290 ("misc: fastrpc: Fix a possible double free") Co-developed-by: Ola Jeppsson <ola@snap.com> Signed-off-by: Ola Jeppsson <ola@snap.com> Signed-off-by: Abel Vesa <abel.vesa@linaro.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> --- drivers/misc/fastrpc.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index fc2173c59f8b..9ecbf673d321 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -316,6 +316,13 @@ static void fastrpc_free_map(struct kref *ref) dma_buf_put(map->buf); } + if (map->fl) { + spin_lock(&map->fl->lock); + list_del(&map->node); + spin_unlock(&map->fl->lock); + map->fl = NULL; + } + kfree(map); } @@ -1266,12 +1273,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, fl->init_mem = NULL; fastrpc_buf_free(imem); err_alloc: - if (map) { - spin_lock(&fl->lock); - list_del(&map->node); - spin_unlock(&fl->lock); - fastrpc_map_put(map); - } + fastrpc_map_put(map); err: kfree(args); @@ -1347,10 +1349,8 @@ static int fastrpc_device_release(struct inode *inode, struct file *file) fastrpc_context_put(ctx); } - list_for_each_entry_safe(map, m, &fl->maps, node) { - list_del(&map->node); + list_for_each_entry_safe(map, m, &fl->maps, node) fastrpc_map_put(map); - } list_for_each_entry_safe(buf, b, &fl->mmaps, node) { list_del(&buf->node); -- 2.25.1
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