Hi Sakari, On 8/2/21 01:05, Sakari Ailus wrote: > Hi Gustavo, > > I missed you already had sent v2... > > On Fri, Jul 30, 2021 at 07:08:13AM -0500, Gustavo A. R. Silva wrote: >> There is a wrong comparison of the total size of the loaded firmware >> css->fw->size with the size of a pointer to struct imgu_fw_header. >> >> Fix this by using the right operand 'struct imgu_fw_header' for >> sizeof, instead of 'struct imgu_fw_header *' and turn binary_header >> into a flexible-array member. Also, adjust the relational operator >> to be '<=' instead of '<', as it seems that the intention of the >> comparison is to determine if the loaded firmware contains any >> 'struct imgu_fw_info' items in the binary_header[] array than merely >> the file_header (struct imgu_fw_bi_file_h). >> >> The replacement of the one-element array with a flexible-array member >> also help with the ongoing efforts to globally enable -Warray-bounds >> and get us closer to being able to tighten the FORTIFY_SOURCE routines >> on memcpy(). >> >> Link: https://github.com/KSPP/linux/issues/79 >> Link: https://github.com/KSPP/linux/issues/109 >> Fixes: 09d290f0ba21 ("media: staging/intel-ipu3: css: Add support for firmware management") >> Cc: stable@xxxxxxxxxxxxxxx >> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> >> --- >> >> It'd be just great if someone that knows this code better can confirm >> these changes are correct. In particular the adjustment of the >> relational operator. Thanks! >> >> Changes in v2: >> - Use flexible array and adjust relational operator, accordingly. > > The operator was just correct. The check is just there to see the firmware > is at least as large as the struct as which it is being accessed. I'm a bit confused, so based on your reply to v1 of this series, this patch is now correct, right? The operator in v1 _was_ correct as long as the one-element array wasn't transformed into a flexible array, right? Notice that generally speaking flexible-array members don't occupy space in the containing structure: $ pahole -C imgu_fw_header drivers/staging/media/ipu3/ipu3-css-fw.o struct imgu_fw_header { struct imgu_fw_bi_file_h file_header; /* 0 72 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ struct imgu_fw_info binary_header[] __attribute__((__aligned__(8))); /* 72 0 */ /* size: 72, cachelines: 2, members: 2 */ /* forced alignments: 1 */ /* last cacheline: 8 bytes */ } __attribute__((__aligned__(8))); $ pahole -C imgu_fw_header drivers/staging/media/ipu3/ipu3-css-fw.o struct imgu_fw_header { struct imgu_fw_bi_file_h file_header; /* 0 72 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ struct imgu_fw_info binary_header[1] __attribute__((__aligned__(8))); /* 72 1200 */ /* size: 1272, cachelines: 20, members: 2 */ /* forced alignments: 1 */ /* last cacheline: 56 bytes */ } __attribute__((__aligned__(8))); So, now that the flexible array transformation is included in the same patch as the bugfix, the operator is changed from '<' to '<=' Can you please confirm if this v2 is now correct? if so, it'd be great to have your Reviewed-by tag. :) Thanks! -- Gustavo > >> - Update changelog text. >> >> drivers/staging/media/ipu3/ipu3-css-fw.c | 2 +- >> drivers/staging/media/ipu3/ipu3-css-fw.h | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/staging/media/ipu3/ipu3-css-fw.c b/drivers/staging/media/ipu3/ipu3-css-fw.c >> index 45aff76198e2..630cb5186b48 100644 >> --- a/drivers/staging/media/ipu3/ipu3-css-fw.c >> +++ b/drivers/staging/media/ipu3/ipu3-css-fw.c >> @@ -124,7 +124,7 @@ int imgu_css_fw_init(struct imgu_css *css) >> /* Check and display fw header info */ >> >> css->fwp = (struct imgu_fw_header *)css->fw->data; >> - if (css->fw->size < sizeof(struct imgu_fw_header *) || >> + if (css->fw->size <= sizeof(struct imgu_fw_header) || >> css->fwp->file_header.h_size != sizeof(struct imgu_fw_bi_file_h)) >> goto bad_fw; >> if (sizeof(struct imgu_fw_bi_file_h) + >> diff --git a/drivers/staging/media/ipu3/ipu3-css-fw.h b/drivers/staging/media/ipu3/ipu3-css-fw.h >> index 3c078f15a295..c0bc57fd678a 100644 >> --- a/drivers/staging/media/ipu3/ipu3-css-fw.h >> +++ b/drivers/staging/media/ipu3/ipu3-css-fw.h >> @@ -171,7 +171,7 @@ struct imgu_fw_bi_file_h { >> >> struct imgu_fw_header { >> struct imgu_fw_bi_file_h file_header; >> - struct imgu_fw_info binary_header[1]; /* binary_nr items */ >> + struct imgu_fw_info binary_header[]; /* binary_nr items */ >> }; >> >> /******************* Firmware functions *******************/ >
