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. Turn binary_header into a flexible-array member[1][2], use the struct_size() helper and fix the wrong size comparison. Notice that the loaded firmware needs to contain at least one 'struct imgu_fw_info' item in the binary_header[] array. It's also worth mentioning that "css->fw->size < struct_size(css->fwp, binary_header, 1)" with binary_header declared as a flexible-array member is equivalent to "css->fw->size < sizeof(struct imgu_fw_header)" with binary_header declared as a one-element array (as in the original code). The replacement of the one-element array with a flexible-array member 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 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> --- Changes in v3: - Integrate the series into a single patch. - Adjust relational operator and use struct_size(). - Update Subject line and changelog text. * Thanks to Dan and Sakari for their feedback. :) Changes in v2: - Use flexible array and adjust relational operator in patch 1. Link: https://lore.kernel.org/linux-hardening/cover.1627646101.git.gustavoars@xxxxxxxxxx/ v1: Link: https://lore.kernel.org/linux-hardening/cover.1627600430.git.gustavoars@xxxxxxxxxx/ drivers/staging/media/ipu3/ipu3-css-fw.c | 7 +++---- drivers/staging/media/ipu3/ipu3-css-fw.h | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/staging/media/ipu3/ipu3-css-fw.c b/drivers/staging/media/ipu3/ipu3-css-fw.c index 45aff76198e2..981693eed815 100644 --- a/drivers/staging/media/ipu3/ipu3-css-fw.c +++ b/drivers/staging/media/ipu3/ipu3-css-fw.c @@ -124,12 +124,11 @@ 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 < struct_size(css->fwp, binary_header, 1) || css->fwp->file_header.h_size != sizeof(struct imgu_fw_bi_file_h)) goto bad_fw; - if (sizeof(struct imgu_fw_bi_file_h) + - css->fwp->file_header.binary_nr * sizeof(struct imgu_fw_info) > - css->fw->size) + if (struct_size(css->fwp, binary_header, + css->fwp->file_header.binary_nr) > css->fw->size) goto bad_fw; dev_info(dev, "loaded firmware version %.64s, %u binaries, %zu bytes\n", 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 *******************/ -- 2.27.0
