From ab3824427b848da10e9fe2727f035bbeecae6ff4 Mon Sep 17 00:00:00 2001 From: Zhou Qingyang Date: Wed, 1 Dec 2021 01:22:53 +0800 Subject: spi: spi-zynq-qspi: Fix a NULL pointer dereference in zynq_qspi_exec_mem_op() In zynq_qspi_exec_mem_op(), kzalloc() is directly used in memset(), which could lead to a NULL pointer dereference on failure of kzalloc(). Fix this bug by adding a check of tmpbuf. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_SPI_ZYNQ_QSPI=m show no new warnings, and our static analyzer no longer warns about this code. Fixes: 67dca5e580f1 ("spi: spi-mem: Add support for Zynq QSPI controller") Signed-off-by: Zhou Qingyang Link: https://lore.kernel.org/r/20211130172253.203700-1-zhou1615@umn.edu Signed-off-by: Mark Brown --- drivers/spi/spi-zynq-qspi.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c index cfa222c9bd5e..78f31b61a2aa 100644 --- a/drivers/spi/spi-zynq-qspi.c +++ b/drivers/spi/spi-zynq-qspi.c @@ -570,6 +570,9 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem, if (op->dummy.nbytes) { tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL); + if (!tmpbuf) + return -ENOMEM; + memset(tmpbuf, 0xff, op->dummy.nbytes); reinit_completion(&xqspi->data_completion); xqspi->txbuf = tmpbuf; -- cgit v1.2.3