diff options
author | Tilman Schmidt <tilman@imap.cc> | 2014-10-11 13:46:30 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2014-10-14 21:05:34 +0200 |
commit | b8324f94202af7dc688576259803a2ef9a98d655 (patch) | |
tree | 05043b6668f823104c3f5eb29451a3b4f0941efd /drivers/isdn/gigaset | |
parent | isdn/gigaset: fix NULL pointer dereference (diff) | |
download | linux-b8324f94202af7dc688576259803a2ef9a98d655.tar.xz linux-b8324f94202af7dc688576259803a2ef9a98d655.zip |
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@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn/gigaset')
-rw-r--r-- | drivers/isdn/gigaset/ev-layer.c | 111 |
1 files changed, 70 insertions, 41 deletions
diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c index 0f699ebd81c5..c8ced12fa452 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 */ |