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Message-Id: <41653e83da96a157ec8ba176595478d9f6ab0da7.1413021630.git.tilman@imap.cc>
Date: Sat, 11 Oct 2014 13:46:30 +0200 (CEST)
From: Tilman Schmidt <tilman@...p.cc>
To: netdev@...r.kernel.org
Cc: David Miller <davem@...emloft.net>, Dave Jones <davej@...hat.com>,
Hansjoerg Lipp <hjlipp@....de>,
Karsten Keil <isdn@...ux-pingi.de>,
isdn4linux@...tserv.isdn4linux.de
Subject: [PATCH 05/12] isdn/gigaset: fix non-heap pointer deallocation
at_state structures may be allocated individually or as part of a
cardstate or bc_state structure. The disconnect() function handled
both cases, creating a risk that it might try to deallocate an
at_state structure that had not been allocated individually.
Fix by splitting disconnect() into two variants handling cases
with and without an associated B channel separately, and adding
an explicit check.
Spotted with Coverity.
Signed-off-by: Tilman Schmidt <tilman@...p.cc>
---
drivers/isdn/gigaset/ev-layer.c | 111 +++++++++++++++++++++++++---------------
1 file changed, 70 insertions(+), 41 deletions(-)
diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c
index 0f699eb..c8ced12 100644
--- a/drivers/isdn/gigaset/ev-layer.c
+++ b/drivers/isdn/gigaset/ev-layer.c
@@ -604,14 +604,14 @@ void gigaset_handle_modem_response(struct cardstate *cs)
}
EXPORT_SYMBOL_GPL(gigaset_handle_modem_response);
-/* disconnect
+/* disconnect_nobc
* process closing of connection associated with given AT state structure
+ * without B channel
*/
-static void disconnect(struct at_state_t **at_state_p)
+static void disconnect_nobc(struct at_state_t **at_state_p,
+ struct cardstate *cs)
{
unsigned long flags;
- struct bc_state *bcs = (*at_state_p)->bcs;
- struct cardstate *cs = (*at_state_p)->cs;
spin_lock_irqsave(&cs->lock, flags);
++(*at_state_p)->seq_index;
@@ -622,23 +622,44 @@ static void disconnect(struct at_state_t **at_state_p)
gig_dbg(DEBUG_EVENT, "Scheduling PC_UMMODE");
cs->commands_pending = 1;
}
- spin_unlock_irqrestore(&cs->lock, flags);
- if (bcs) {
- /* B channel assigned: invoke hardware specific handler */
- cs->ops->close_bchannel(bcs);
- /* notify LL */
- if (bcs->chstate & (CHS_D_UP | CHS_NOTIFY_LL)) {
- bcs->chstate &= ~(CHS_D_UP | CHS_NOTIFY_LL);
- gigaset_isdn_hupD(bcs);
- }
- } else {
- /* no B channel assigned: just deallocate */
- spin_lock_irqsave(&cs->lock, flags);
+ /* check for and deallocate temporary AT state */
+ if (!list_empty(&(*at_state_p)->list)) {
list_del(&(*at_state_p)->list);
kfree(*at_state_p);
*at_state_p = NULL;
- spin_unlock_irqrestore(&cs->lock, flags);
+ }
+
+ spin_unlock_irqrestore(&cs->lock, flags);
+}
+
+/* disconnect_bc
+ * process closing of connection associated with given AT state structure
+ * and B channel
+ */
+static void disconnect_bc(struct at_state_t *at_state,
+ struct cardstate *cs, struct bc_state *bcs)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cs->lock, flags);
+ ++at_state->seq_index;
+
+ /* revert to selected idle mode */
+ if (!cs->cidmode) {
+ cs->at_state.pending_commands |= PC_UMMODE;
+ gig_dbg(DEBUG_EVENT, "Scheduling PC_UMMODE");
+ cs->commands_pending = 1;
+ }
+ spin_unlock_irqrestore(&cs->lock, flags);
+
+ /* invoke hardware specific handler */
+ cs->ops->close_bchannel(bcs);
+
+ /* notify LL */
+ if (bcs->chstate & (CHS_D_UP | CHS_NOTIFY_LL)) {
+ bcs->chstate &= ~(CHS_D_UP | CHS_NOTIFY_LL);
+ gigaset_isdn_hupD(bcs);
}
}
@@ -646,7 +667,7 @@ static void disconnect(struct at_state_t **at_state_p)
* get a free AT state structure: either one of those associated with the
* B channels of the Gigaset device, or if none of those is available,
* a newly allocated one with bcs=NULL
- * The structure should be freed by calling disconnect() after use.
+ * The structure should be freed by calling disconnect_nobc() after use.
*/
static inline struct at_state_t *get_free_channel(struct cardstate *cs,
int cid)
@@ -1057,7 +1078,7 @@ static void do_action(int action, struct cardstate *cs,
struct event_t *ev)
{
struct at_state_t *at_state = *p_at_state;
- struct at_state_t *at_state2;
+ struct bc_state *bcs2;
unsigned long flags;
int channel;
@@ -1156,8 +1177,8 @@ static void do_action(int action, struct cardstate *cs,
break;
case ACT_RING:
/* get fresh AT state structure for new CID */
- at_state2 = get_free_channel(cs, ev->parameter);
- if (!at_state2) {
+ at_state = get_free_channel(cs, ev->parameter);
+ if (!at_state) {
dev_warn(cs->dev,
"RING ignored: could not allocate channel structure\n");
break;
@@ -1166,16 +1187,16 @@ static void do_action(int action, struct cardstate *cs,
/* initialize AT state structure
* note that bcs may be NULL if no B channel is free
*/
- at_state2->ConState = 700;
+ at_state->ConState = 700;
for (i = 0; i < STR_NUM; ++i) {
- kfree(at_state2->str_var[i]);
- at_state2->str_var[i] = NULL;
+ kfree(at_state->str_var[i]);
+ at_state->str_var[i] = NULL;
}
- at_state2->int_var[VAR_ZCTP] = -1;
+ at_state->int_var[VAR_ZCTP] = -1;
spin_lock_irqsave(&cs->lock, flags);
- at_state2->timer_expires = RING_TIMEOUT;
- at_state2->timer_active = 1;
+ at_state->timer_expires = RING_TIMEOUT;
+ at_state->timer_active = 1;
spin_unlock_irqrestore(&cs->lock, flags);
break;
case ACT_ICALL:
@@ -1213,14 +1234,17 @@ static void do_action(int action, struct cardstate *cs,
case ACT_DISCONNECT:
cs->cur_at_seq = SEQ_NONE;
at_state->cid = -1;
- if (bcs && cs->onechannel && cs->dle) {
+ if (!bcs) {
+ disconnect_nobc(p_at_state, cs);
+ } else if (cs->onechannel && cs->dle) {
/* Check for other open channels not needed:
* DLE only used for M10x with one B channel.
*/
at_state->pending_commands |= PC_DLE0;
cs->commands_pending = 1;
- } else
- disconnect(p_at_state);
+ } else {
+ disconnect_bc(at_state, cs, bcs);
+ }
break;
case ACT_FAKEDLE0:
at_state->int_var[VAR_ZDLE] = 0;
@@ -1228,25 +1252,27 @@ static void do_action(int action, struct cardstate *cs,
/* fall through */
case ACT_DLE0:
cs->cur_at_seq = SEQ_NONE;
- at_state2 = &cs->bcs[cs->curchannel].at_state;
- disconnect(&at_state2);
+ bcs2 = cs->bcs + cs->curchannel;
+ disconnect_bc(&bcs2->at_state, cs, bcs2);
break;
case ACT_ABORTHUP:
cs->cur_at_seq = SEQ_NONE;
dev_warn(cs->dev, "Could not hang up.\n");
at_state->cid = -1;
- if (bcs && cs->onechannel)
+ if (!bcs)
+ disconnect_nobc(p_at_state, cs);
+ else if (cs->onechannel)
at_state->pending_commands |= PC_DLE0;
else
- disconnect(p_at_state);
+ disconnect_bc(at_state, cs, bcs);
schedule_init(cs, MS_RECOVER);
break;
case ACT_FAILDLE0:
cs->cur_at_seq = SEQ_NONE;
dev_warn(cs->dev, "Error leaving DLE mode.\n");
cs->dle = 0;
- at_state2 = &cs->bcs[cs->curchannel].at_state;
- disconnect(&at_state2);
+ bcs2 = cs->bcs + cs->curchannel;
+ disconnect_bc(&bcs2->at_state, cs, bcs2);
schedule_init(cs, MS_RECOVER);
break;
case ACT_FAILDLE1:
@@ -1275,14 +1301,14 @@ static void do_action(int action, struct cardstate *cs,
if (reinit_and_retry(cs, channel) < 0) {
dev_warn(cs->dev,
"Could not get a call ID. Cannot dial.\n");
- at_state2 = &cs->bcs[channel].at_state;
- disconnect(&at_state2);
+ bcs2 = cs->bcs + channel;
+ disconnect_bc(&bcs2->at_state, cs, bcs2);
}
break;
case ACT_ABORTCID:
cs->cur_at_seq = SEQ_NONE;
- at_state2 = &cs->bcs[cs->curchannel].at_state;
- disconnect(&at_state2);
+ bcs2 = cs->bcs + cs->curchannel;
+ disconnect_bc(&bcs2->at_state, cs, bcs2);
break;
case ACT_DIALING:
@@ -1291,7 +1317,10 @@ static void do_action(int action, struct cardstate *cs,
break;
case ACT_ABORTACCEPT: /* hangup/error/timeout during ICALL procssng */
- disconnect(p_at_state);
+ if (bcs)
+ disconnect_bc(at_state, cs, bcs);
+ else
+ disconnect_nobc(p_at_state, cs);
break;
case ACT_ABORTDIAL: /* error/timeout during dial preparation */
--
1.9.2.459.g68773ac
--
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