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    SubjectRe: [PATCH] wifi: p54: Annotate struct p54_cal_database with __counted_by
    On Mon, Oct 09, 2023 at 10:55:32AM -0400, Jason Andryuk wrote:
    > This is the function that creates struct p54_cal_database:
    >
    > static struct p54_cal_database *p54_convert_db(struct pda_custom_wrapper *src,
    > size_t total_len)
    > {
    > struct p54_cal_database *dst;
    > size_t payload_len, entries, entry_size, offset;
    >
    > payload_len = le16_to_cpu(src->len);
    > entries = le16_to_cpu(src->entries);
    > entry_size = le16_to_cpu(src->entry_size);
    > offset = le16_to_cpu(src->offset);
    > if (((entries * entry_size + offset) != payload_len) ||
    > (payload_len + sizeof(*src) != total_len))
    > return NULL;
    >
    > dst = kmalloc(sizeof(*dst) + payload_len, GFP_KERNEL);
    > if (!dst)
    > return NULL;
    >
    > dst->entries = entries;
    > dst->entry_size = entry_size;
    > dst->offset = offset;
    > dst->len = payload_len;
    >
    > memcpy(dst->data, src->data, payload_len);
    > return dst;
    > }
    >
    > You can see that kmalloc is performed with `sizeof(*dst) +
    > payload_len`, and payload_len is assigned to ->len.
    >
    > I don't read Coccinelle, but, if this patch was auto-generated, I
    > wonder if the script has an error.

    It seems that my Coccinelle script got confused by this:

    p54_convert_output_limits():

    priv->output_limit = kmalloc(data[1] *
    sizeof(struct pda_channel_output_limit) +
    sizeof(*priv->output_limit), GFP_KERNEL);

    ...

    priv->output_limit->entry_size =
    sizeof(struct pda_channel_output_limit);
    priv->output_limit->len = priv->output_limit->entry_size *
    priv->output_limit->entries +
    priv->output_limit->offset;

    It thought "sizeof(struct pda_channel_output_limit)" was the element
    count, since it wasn't able to identify the array member here.

    Regardless, I've sent a v2 now. :)

    --
    Kees Cook

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