From eaf75d1815dad230dac2f1e8f1dc0349b2d50071 Mon Sep 17 00:00:00 2001 From: Quinn Tran Date: Thu, 1 Feb 2018 10:33:17 -0800 Subject: [PATCH] scsi: qla2xxx: Fix double free bug after firmware timeout This patch is based on Max's original patch. When the qla2xxx firmware is unavailable, eventually qla2x00_sp_timeout() is reached, which calls the timeout function and frees the srb_t instance. The timeout function always resolves to qla2x00_async_iocb_timeout(), which invokes another callback function called "done". All of these qla2x00_*_sp_done() callbacks also free the srb_t instance; after returning to qla2x00_sp_timeout(), it is freed again. The fix is to remove the "sp->free(sp)" call from qla2x00_sp_timeout() and add it to those code paths in qla2x00_async_iocb_timeout() which do not already free the object. This is how it looks like with KASAN: BUG: KASAN: use-after-free in qla2x00_sp_timeout+0x228/0x250 Read of size 8 at addr ffff88278147a590 by task swapper/2/0 Allocated by task 1502: save_stack+0x33/0xa0 kasan_kmalloc+0xa0/0xd0 kmem_cache_alloc+0xb8/0x1c0 mempool_alloc+0xd6/0x260 qla24xx_async_gnl+0x3c5/0x1100 Freed by task 0: save_stack+0x33/0xa0 kasan_slab_free+0x72/0xc0 kmem_cache_free+0x75/0x200 qla24xx_async_gnl_sp_done+0x556/0x9e0 qla2x00_async_iocb_timeout+0x1c7/0x420 qla2x00_sp_timeout+0x16d/0x250 call_timer_fn+0x36/0x200 The buggy address belongs to the object at ffff88278147a440 which belongs to the cache qla2xxx_srbs of size 344 The buggy address is located 336 bytes inside of 344-byte region [ffff88278147a440, ffff88278147a598) Reported-by: Max Kellermann Signed-off-by: Quinn Tran Signed-off-by: Himanshu Madhani Cc: Max Kellermann Signed-off-by: Martin K. Petersen --- drivers/scsi/qla2xxx/qla_init.c | 23 +++-------------------- 1 file changed, 3 insertions(+), 20 deletions(-) diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c index aececf664654..2dea1129d396 100644 --- a/drivers/scsi/qla2xxx/qla_init.c +++ b/drivers/scsi/qla2xxx/qla_init.c @@ -59,8 +59,6 @@ qla2x00_sp_timeout(struct timer_list *t) req->outstanding_cmds[sp->handle] = NULL; iocb = &sp->u.iocb_cmd; iocb->timeout(sp); - if (sp->type != SRB_ELS_DCMD) - sp->free(sp); spin_unlock_irqrestore(&vha->hw->hardware_lock, flags); } @@ -102,7 +100,6 @@ qla2x00_async_iocb_timeout(void *data) srb_t *sp = data; fc_port_t *fcport = sp->fcport; struct srb_iocb *lio = &sp->u.iocb_cmd; - struct event_arg ea; if (fcport) { ql_dbg(ql_dbg_disc, fcport->vha, 0x2071, @@ -117,25 +114,13 @@ qla2x00_async_iocb_timeout(void *data) switch (sp->type) { case SRB_LOGIN_CMD: - if (!fcport) - break; /* Retry as needed. */ lio->u.logio.data[0] = MBS_COMMAND_ERROR; lio->u.logio.data[1] = lio->u.logio.flags & SRB_LOGIN_RETRIED ? QLA_LOGIO_LOGIN_RETRIED : 0; - memset(&ea, 0, sizeof(ea)); - ea.event = FCME_PLOGI_DONE; - ea.fcport = sp->fcport; - ea.data[0] = lio->u.logio.data[0]; - ea.data[1] = lio->u.logio.data[1]; - ea.sp = sp; - qla24xx_handle_plogi_done_event(fcport->vha, &ea); + sp->done(sp, QLA_FUNCTION_TIMEOUT); break; case SRB_LOGOUT_CMD: - if (!fcport) - break; - qlt_logo_completion_handler(fcport, QLA_FUNCTION_TIMEOUT); - break; case SRB_CT_PTHRU_CMD: case SRB_MB_IOCB: case SRB_NACK_PLOGI: @@ -235,12 +220,10 @@ static void qla2x00_async_logout_sp_done(void *ptr, int res) { srb_t *sp = ptr; - struct srb_iocb *lio = &sp->u.iocb_cmd; sp->fcport->flags &= ~(FCF_ASYNC_SENT | FCF_ASYNC_ACTIVE); - if (!test_bit(UNLOADING, &sp->vha->dpc_flags)) - qla2x00_post_async_logout_done_work(sp->vha, sp->fcport, - lio->u.logio.data); + sp->fcport->login_gen++; + qlt_logo_completion_handler(sp->fcport, res); sp->free(sp); }