[PATCH 5.4 07/72] firmware_loader: fix memory leak for paged buffer

Greg Kroah-Hartman
2020-09-21T16:53:23Z

From: Prateek Sood <prsood@codeaurora.org>

commit 4965b8cd1bc1ffb017e5c58e622da82b55e49414 upstream.

vfree() is being called on paged buffer allocated
using alloc_page() and mapped using vmap().

Freeing of pages in vfree() relies on nr_pages of
struct vm_struct. vmap() does not update nr_pages.
It can lead to memory leaks.

Fixes: ddaf29fd9bb6 ("firmware: Free temporary page table after vmapping")
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1597957070-27185-1-git-send-email-prsood@codeaurora.org
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/base/firmware_loader/firmware.h | 2 ++
drivers/base/firmware_loader/main.c | 17 +++++++++++------
2 files changed, 13 insertions(+), 6 deletions(-)

--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -139,10 +139,12 @@ int assign_fw(struct firmware *fw, struc
void fw_free_paged_buf(struct fw_priv *fw_priv);
int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
int fw_map_paged_buf(struct fw_priv *fw_priv);
+bool fw_is_paged_buf(struct fw_priv *fw_priv);
#else
static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) { return -ENXIO; }
static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
+static inline bool fw_is_paged_buf(struct fw_priv *fw_priv) { return false; }
#endif

#endif /* __FIRMWARE_LOADER_H */
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -252,9 +252,11 @@ static void __free_fw_priv(struct kref *
list_del(&fw_priv->list);
spin_unlock(&fwc->lock);

- fw_free_paged_buf(fw_priv); /* free leftover pages */
- if (!fw_priv->allocated_size)
+ if (fw_is_paged_buf(fw_priv))
+ fw_free_paged_buf(fw_priv);
+ else if (!fw_priv->allocated_size)
vfree(fw_priv->data);
+
kfree_const(fw_priv->fw_name);
kfree(fw_priv);
}
@@ -268,6 +270,11 @@ static void free_fw_priv(struct fw_priv
}

#ifdef CONFIG_FW_LOADER_PAGED_BUF
+bool fw_is_paged_buf(struct fw_priv *fw_priv)
+{
+ return fw_priv->is_paged_buf;
+}
+
void fw_free_paged_buf(struct fw_priv *fw_priv)
{
int i;
@@ -275,6 +282,8 @@ void fw_free_paged_buf(struct fw_priv *f
if (!fw_priv->pages)
return;

+ vunmap(fw_priv->data);
+
for (i = 0; i < fw_priv->nr_pages; i++)
__free_page(fw_priv->pages[i]);
kvfree(fw_priv->pages);
@@ -328,10 +337,6 @@ int fw_map_paged_buf(struct fw_priv *fw_
if (!fw_priv->data)
return -ENOMEM;

- /* page table is no longer needed after mapping, let's free */
- kvfree(fw_priv->pages);
- fw_priv->pages = NULL;
-
return 0;
}
#endif