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Tue, 15 Sep 2026 00:26:10 -0700 (PDT) Received: from ryzen.lan ([2601:644:8000:7a86::e35]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2dd2ccadb4fsm61248325ad.2.2026.09.15.00.26.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2026 00:26:09 -0700 (PDT) From: Rosen Penev To: dmaengine@vger.kernel.org Cc: Vinod Koul , Frank Li , linux-kernel@vger.kernel.org (open list) Subject: [PATCHv4] dmaengine: bestcomm: gen_bd: fix out-of-bounds access in PSC parameter lookup Date: Tue, 15 Sep 2026 00:26:08 -0700 Message-ID: <20260915072608.57887-1-rosenp@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The bcom_psc_params[] array has 6 entries (indices 0-5), but bcom_psc_gen_bd_rx_init() checked against MPC52xx_PSC_MAXNUM which can be 12 when CONFIG_PPC_MPC512x is set, allowing indices 6-11 to pass and read past the array. The tx init function had no bounds check at all. A malformed device tree with a large cell-index could therefore trigger an out-of-bounds read. The garbage initiator and ipr values would then be used for MMIO writes via out_8(&bcom_eng->regs->ipr[...], ...), potentially causing out-of-bounds MMIO accesses. Assisted-by: LLM Signed-off-by: Rosen Penev --- v4: actually bcom_psc_gen_bd_tx_init is still needed. v3: reduce bounds check to single function. It's not used anywhere anyway. v2: fix title drivers/dma/bestcomm/gen_bd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/bestcomm/gen_bd.c b/drivers/dma/bestcomm/gen_bd.c index 61b5746e1a97..7bbe9cd7b39c 100644 --- a/drivers/dma/bestcomm/gen_bd.c +++ b/drivers/dma/bestcomm/gen_bd.c @@ -321,7 +321,7 @@ static const struct bcom_psc_params bcom_psc_params[] = { struct bcom_task * bcom_psc_gen_bd_rx_init(unsigned psc_num, int queue_len, phys_addr_t fifo, int maxbufsize) { - if (psc_num >= MPC52xx_PSC_MAXNUM) + if (psc_num >= ARRAY_SIZE(bcom_psc_params)) return NULL; return bcom_gen_bd_rx_init(queue_len, fifo, @@ -342,6 +342,9 @@ EXPORT_SYMBOL_GPL(bcom_psc_gen_bd_rx_init); struct bcom_task * bcom_psc_gen_bd_tx_init(unsigned psc_num, int queue_len, phys_addr_t fifo) { + if (psc_num >= ARRAY_SIZE(bcom_psc_params)) + return NULL; + struct psc; return bcom_gen_bd_tx_init(queue_len, fifo, bcom_psc_params[psc_num].tx_initiator, -- 2.55.0