From: Jordy Zomer jordy@pwning.systems
stable inclusion from stable-v5.10.99 commit 5d40f1bdad3dd1a177f21a90ad4353c1ed40ba3a bugzilla: https://gitee.com/openeuler/kernel/issues/I55O7H
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 92c4cfaee6872038563c5b6f2e8e613f9d84d47d upstream.
It appears like nr could be a Spectre v1 gadget as it's supplied by a user and used as an array index. Prevent the contents of kernel memory from being leaked to userspace via speculative execution by using array_index_nospec.
Signed-off-by: Jordy Zomer jordy@pwning.systems Fixes: c02a81fba74f ("dma-buf: Add dma-buf heaps framework") Cc: stable@vger.kernel.org # v5.6+ Acked-by: John Stultz john.stultz@linaro.org Signed-off-by: Sumit Semwal sumit.semwal@linaro.org [sumits: added fixes and cc: stable tags] Link: https://patchwork.freedesktop.org/patch/msgid/20220129150604.3461652-1-jordy... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/dma-buf/dma-heap.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index afd22c9dbdcf..798f86fcd50f 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -14,6 +14,7 @@ #include <linux/xarray.h> #include <linux/list.h> #include <linux/slab.h> +#include <linux/nospec.h> #include <linux/uaccess.h> #include <linux/syscalls.h> #include <linux/dma-heap.h> @@ -123,6 +124,7 @@ static long dma_heap_ioctl(struct file *file, unsigned int ucmd, if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds)) return -EINVAL;
+ nr = array_index_nospec(nr, ARRAY_SIZE(dma_heap_ioctl_cmds)); /* Get the kernel ioctl cmd that matches */ kcmd = dma_heap_ioctl_cmds[nr];