On Fri, Jul 30, 2021 at 10:49:50AM +0300, Dan Carpenter wrote: > On Thu, Jul 29, 2021 at 06:22:40PM -0500, Gustavo A. R. Silva wrote: > > There is a regular need in the kernel to provide a way to declare having > > a dynamically sized set of trailing elements in a structure. Kernel code > > should always use “flexible array members”[1] for these cases. The older > > style of one-element or zero-length arrays should no longer be used[2]. > > > > Replace a one-element array with a flexible-array member in struct > > imgu_fw_header and use the struct_size() helper. > > > > This also helps with the ongoing efforts to globally enable > > -Warray-bounds and get us closer to being able to tighten the > > FORTIFY_SOURCE routines on memcpy(). > > > > [1] https://en.wikipedia.org/wiki/Flexible_array_member > > [2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays > > > > Link: https://github.com/KSPP/linux/issues/79 > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > > --- > > drivers/staging/media/ipu3/ipu3-css-fw.c | 5 ++--- > > drivers/staging/media/ipu3/ipu3-css-fw.h | 2 +- > > 2 files changed, 3 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/staging/media/ipu3/ipu3-css-fw.c b/drivers/staging/media/ipu3/ipu3-css-fw.c > > index ab021afff954..3b7df1128840 100644 > > --- a/drivers/staging/media/ipu3/ipu3-css-fw.c > > +++ b/drivers/staging/media/ipu3/ipu3-css-fw.c > > @@ -127,9 +127,8 @@ int imgu_css_fw_init(struct imgu_css *css) > > if (css->fw->size < sizeof(struct imgu_fw_header) || > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Originally this was sizeof() the pointer which is clearly wrong. Then > patch 1 changed it to force that binary_header[] had at least one > element, but now it's changed again to say that binary_header[] can have > zero elements. So either patch 1 or patch 2 is wrong. > > I feel like the probably the correct fix is to just fold these two > patches together and say that binary_header[] with zero elements is > allowed. But I don't know this code well. Oops... I forgot to tag this one for stable, too. But it would probably be better to fold both of these into a single patch as you suggest. To me these two pieces of code suggest that binary_header[] should not be declared as a one-element array, but a flexible one instead: 130 if (sizeof(struct imgu_fw_bi_file_h) + 131 css->fwp->file_header.binary_nr * sizeof(struct imgu_fw_info) > 132 css->fw->size) 133 goto bad_fw; ... 147 for (i = 0; i < binary_nr; i++) { 148 struct imgu_fw_info *bi = &css->fwp->binary_header[i]; ... Thanks -- Gustavo
