From: Len Baker Date: Sun, 19 Sep 2021 09:45:39 +0000 (+0200) Subject: aio: Prefer struct_size over open coded arithmetic X-Git-Tag: v5.16-rc1~176^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6446c4fb12ecc130ed9b4333372426b305a35e2b;p=thirdparty%2Fkernel%2Flinux.git aio: Prefer 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. So, use the struct_size() helper to do the arithmetic instead of the argument "size + size * count" in the kzalloc() function. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Signed-off-by: Len Baker Reviewed-by: Gustavo A. R. Silva Signed-off-by: Gustavo A. R. Silva --- diff --git a/fs/aio.c b/fs/aio.c index 51b08ab01dffc..c2978c0b872c8 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -659,8 +659,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) new_nr = (table ? table->nr : 1) * 4; spin_unlock(&mm->ioctx_lock); - table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * - new_nr, GFP_KERNEL); + table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL); if (!table) return -ENOMEM;