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spi: spi-zynq-qspi: Fix a NULL pointer dereference in zynq_qspi_exec_mem_op()

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[ Upstream commit ab3824427b ]

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: 67dca5e580 ("spi: spi-mem: Add support for Zynq QSPI controller")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
Link: https://lore.kernel.org/r/20211130172253.203700-1-zhou1615@umn.edu
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zhou Qingyang 2021-12-01 01:22:53 +08:00 committed by Greg Kroah-Hartman
parent 2378f94c8d
commit 3c32405d64
1 changed files with 3 additions and 0 deletions
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3
drivers/spi/spi-zynq-qspi.c
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@ -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;