From 117d5b6d00ee02f73d7065fe906e2ef1af74bb68 Mon Sep 17 00:00:00 2001 From: Len Baker Date: Sun, 17 Oct 2021 11:56:50 +0200 Subject: [PATCH] nvmet: use struct_size over open coded arithmetic As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors. In this case this is not actually dynamic size: all the operands involved in the calculation are constant values. However it is better to refactor this anyway, just to keep the open-coded math idiom out of code. So, use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the kmalloc() function. This code was detected with the help of Coccinelle and audited and fixed manually. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Signed-off-by: Len Baker Signed-off-by: Christoph Hellwig --- drivers/nvme/target/admin-cmd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c index 6e75890bc8d9..403de678fd06 100644 --- a/drivers/nvme/target/admin-cmd.c +++ b/drivers/nvme/target/admin-cmd.c @@ -278,8 +278,8 @@ static void nvmet_execute_get_log_page_ana(struct nvmet_req *req) u16 status; status = NVME_SC_INTERNAL; - desc = kmalloc(sizeof(struct nvme_ana_group_desc) + - NVMET_MAX_NAMESPACES * sizeof(__le32), GFP_KERNEL); + desc = kmalloc(struct_size(desc, nsids, NVMET_MAX_NAMESPACES), + GFP_KERNEL); if (!desc) goto out;