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Subject[PATCH 16/16] drivers, net, intersil: convert request_context.refcount from atomic_t to refcount_t
Date
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
drivers/net/wireless/intersil/orinoco/orinoco_usb.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
index 98e1380..95dd03e 100644
--- a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
+++ b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
@@ -64,6 +64,7 @@
#include <linux/etherdevice.h>
#include <linux/wireless.h>
#include <linux/firmware.h>
+#include <linux/refcount.h>

#include "mic.h"
#include "orinoco.h"
@@ -268,7 +269,7 @@ enum ezusb_state {

struct request_context {
struct list_head list;
- atomic_t refcount;
+ refcount_t refcount;
struct completion done; /* Signals that CTX is dead */
int killed;
struct urb *outurb; /* OUT for req pkt */
@@ -298,7 +299,7 @@ static inline u8 ezusb_reply_inc(u8 count)

static void ezusb_request_context_put(struct request_context *ctx)
{
- if (!atomic_dec_and_test(&ctx->refcount))
+ if (!refcount_dec_and_test(&ctx->refcount))
return;

WARN_ON(!ctx->done.done);
@@ -328,7 +329,7 @@ static void ezusb_request_timerfn(u_long _ctx)
} else {
ctx->state = EZUSB_CTX_RESP_TIMEOUT;
dev_dbg(&ctx->outurb->dev->dev, "couldn't unlink\n");
- atomic_inc(&ctx->refcount);
+ refcount_inc(&ctx->refcount);
ctx->killed = 1;
ezusb_ctx_complete(ctx);
ezusb_request_context_put(ctx);
@@ -361,7 +362,7 @@ static struct request_context *ezusb_alloc_ctx(struct ezusb_priv *upriv,
ctx->out_rid = out_rid;
ctx->in_rid = in_rid;

- atomic_set(&ctx->refcount, 1);
+ refcount_set(&ctx->refcount, 1);
init_completion(&ctx->done);

setup_timer(&ctx->timer, ezusb_request_timerfn, (u_long)ctx);
@@ -469,7 +470,7 @@ static void ezusb_req_queue_run(struct ezusb_priv *upriv)
list_move_tail(&ctx->list, &upriv->req_active);

if (ctx->state == EZUSB_CTX_QUEUED) {
- atomic_inc(&ctx->refcount);
+ refcount_inc(&ctx->refcount);
result = usb_submit_urb(ctx->outurb, GFP_ATOMIC);
if (result) {
ctx->state = EZUSB_CTX_REQSUBMIT_FAIL;
@@ -507,7 +508,7 @@ static void ezusb_req_enqueue_run(struct ezusb_priv *upriv,
spin_unlock_irqrestore(&upriv->req_lock, flags);
goto done;
}
- atomic_inc(&ctx->refcount);
+ refcount_inc(&ctx->refcount);
list_add_tail(&ctx->list, &upriv->req_pending);
spin_unlock_irqrestore(&upriv->req_lock, flags);

@@ -1464,7 +1465,7 @@ static inline void ezusb_delete(struct ezusb_priv *upriv)
int err;

ctx = list_entry(item, struct request_context, list);
- atomic_inc(&ctx->refcount);
+ refcount_inc(&ctx->refcount);

ctx->outurb->transfer_flags |= URB_ASYNC_UNLINK;
err = usb_unlink_urb(ctx->outurb);
--
2.7.4
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