From cf20c3533efc89578ace94fa20a9e63446223c72 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 29 Aug 2022 10:05:30 +0200 Subject: [PATCH] misc: fastrpc: fix memory corruption on open commit d245f43aab2b61195d8ebb64cef7b5a08c590ab4 upstream. The probe session-duplication overflow check incremented the session count also when there were no more available sessions so that memory beyond the fixed-size slab-allocated session array could be corrupted in fastrpc_session_alloc() on open(). Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model") Cc: stable@vger.kernel.org # 5.1 Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20220829080531.29681-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/misc/fastrpc.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index cbb90e0c9ccf5..cf5705776c4f6 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -1555,7 +1555,7 @@ static int fastrpc_cb_probe(struct platform_device *pdev) spin_unlock_irqrestore(&cctx->lock, flags); return -ENOSPC; } - sess = &cctx->session[cctx->sesscount]; + sess = &cctx->session[cctx->sesscount++]; sess->used = false; sess->valid = true; sess->dev = dev; @@ -1568,13 +1568,12 @@ static int fastrpc_cb_probe(struct platform_device *pdev) struct fastrpc_session_ctx *dup_sess; for (i = 1; i < sessions; i++) { - if (cctx->sesscount++ >= FASTRPC_MAX_SESSIONS) + if (cctx->sesscount >= FASTRPC_MAX_SESSIONS) break; - dup_sess = &cctx->session[cctx->sesscount]; + dup_sess = &cctx->session[cctx->sesscount++]; memcpy(dup_sess, sess, sizeof(*dup_sess)); } } - cctx->sesscount++; spin_unlock_irqrestore(&cctx->lock, flags); rc = dma_set_mask(dev, DMA_BIT_MASK(32)); if (rc) {