Hi Dan,
Thank you for the patch.
On Thu, Aug 04, 2022 at 05:32:39PM +0300, Dan Carpenter wrote:
> There are two issues here:
>
> 1) The "len" variable needs to be checked before the very first write.
> Otherwise if omap2_iommu_dump_ctx() with "bytes" less than 32 it is a
> buffer overflow.
> 2) The snprintf() function returns the number of bytes that *would* have
> been copied if there were enough space. But we want to know the
> number of bytes which were *actually* copied so use scnprintf()
> instead.
>
> Fixes: bd4396f09a4a ("iommu/omap: Consolidate OMAP IOMMU modules")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/iommu/omap-iommu-debug.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
> index a99afb5d9011..259f65291d90 100644
> --- a/drivers/iommu/omap-iommu-debug.c
> +++ b/drivers/iommu/omap-iommu-debug.c
> @@ -32,12 +32,12 @@ static inline bool is_omap_iommu_detached(struct omap_iommu *obj)
> ssize_t bytes; \
> const char *str = "%20s: %08x\n"; \
> const int maxcol = 32; \
> - bytes = snprintf(p, maxcol, str, __stringify(name), \
> + if (len < maxcol) \
> + goto out; \
> + bytes = scnprintf(p, maxcol, str, __stringify(name), \
> iommu_read_reg(obj, MMU_##name)); \
> p += bytes; \
> len -= bytes; \
> - if (len < maxcol) \
> - goto out; \
> } while (0)
This could would really benefit from being rewritten using a static
table of register name and offset and a loop that iterates over it.
Still, this is a valid bug fix, so
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> static ssize_t
--
Regards,
Laurent Pinchart
