From bippy-c9c4e1df01b2 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-4441: spi: spi-zynq-qspi: Fix a NULL pointer dereference in zynq_qspi_exec_mem_op() Description =========== In the Linux kernel, the following vulnerability has been resolved: 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. The Linux kernel CVE team has assigned CVE-2021-4441 to this issue. Affected and fixed versions =========================== Issue introduced in 5.2 with commit 67dca5e580f1 and fixed in 5.4.182 with commit df14d2bed8e2 Issue introduced in 5.2 with commit 67dca5e580f1 and fixed in 5.10.103 with commit 2efece1368ae Issue introduced in 5.2 with commit 67dca5e580f1 and fixed in 5.15.26 with commit 3c32405d6474 Issue introduced in 5.2 with commit 67dca5e580f1 and fixed in 5.16.12 with commit b9dd08cbebe0 Issue introduced in 5.2 with commit 67dca5e580f1 and fixed in 5.17 with commit ab3824427b84 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2021-4441 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/spi/spi-zynq-qspi.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/df14d2bed8e2455878e046e67123d9ecb2e79056 https://git.kernel.org/stable/c/2efece1368aeee2d2552c7ec36aeb676c4d4c95f https://git.kernel.org/stable/c/3c32405d6474a21f7d742828e73c13e326dcae82 https://git.kernel.org/stable/c/b9dd08cbebe0c593c49bf86d2012a431494e54cb https://git.kernel.org/stable/c/ab3824427b848da10e9fe2727f035bbeecae6ff4