On Tue, Jul 27, 2021 at 01:57:52PM -0700, Kees Cook wrote:
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Wrap the target region in a common named structure. This additionally fixes a theoretical misalignment of the copy (since the size of "buf" changes between 64-bit and 32-bit, but this is likely never built for 64-bit).
FWIW, I think this code is totally broken on 64-bit (which appears to not be a "real" build configuration): it would either always fail (with an uninitialized data->buf_size) or would cause corruption in userspace due to the copy_to_user() in the call path against an uninitialized data->buf value:
omap3isp_stat_request_statistics_time32(...) struct omap3isp_stat_data data64; ... omap3isp_stat_request_statistics(stat, &data64);
int omap3isp_stat_request_statistics(struct ispstat *stat, struct omap3isp_stat_data *data) ... buf = isp_stat_buf_get(stat, data);
static struct ispstat_buffer *isp_stat_buf_get(struct ispstat *stat, struct omap3isp_stat_data *data) ... if (buf->buf_size > data->buf_size) { ... return ERR_PTR(-EINVAL); } ... rval = copy_to_user(data->buf, buf->virt_addr, buf->buf_size);
Regardless, additionally initialize data64 to be zero-filled to avoid undefined behavior.
Fixes: 378e3f81cb56 ("media: omap3isp: support 64-bit version of omap3isp_stat_data") Signed-off-by: Kees Cook keescook@chromium.org
drivers/media/platform/omap3isp/ispstat.c | 5 +-- include/uapi/linux/omap3isp.h | 44 +++++++++++++++++------ 2 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/drivers/media/platform/omap3isp/ispstat.c b/drivers/media/platform/omap3isp/ispstat.c index 5b9b57f4d9bf..ea8222fed38e 100644 --- a/drivers/media/platform/omap3isp/ispstat.c +++ b/drivers/media/platform/omap3isp/ispstat.c @@ -512,7 +512,7 @@ int omap3isp_stat_request_statistics(struct ispstat *stat, int omap3isp_stat_request_statistics_time32(struct ispstat *stat, struct omap3isp_stat_data_time32 *data) {
- struct omap3isp_stat_data data64;
struct omap3isp_stat_data data64 = { }; int ret;
ret = omap3isp_stat_request_statistics(stat, &data64);
@@ -521,7 +521,8 @@ int omap3isp_stat_request_statistics_time32(struct ispstat *stat,
data->ts.tv_sec = data64.ts.tv_sec; data->ts.tv_usec = data64.ts.tv_usec;
- memcpy(&data->buf, &data64.buf, sizeof(*data) - sizeof(data->ts));
- data->buf = (uintptr_t)data64.buf;
- memcpy(&data->frame, &data64.buf, sizeof(data->frame));
I think this should be:
memcpy(..., &data64.frame, ...);
instead.
-- Gustavo
return 0; } diff --git a/include/uapi/linux/omap3isp.h b/include/uapi/linux/omap3isp.h index 87b55755f4ff..0a16af91621f 100644 --- a/include/uapi/linux/omap3isp.h +++ b/include/uapi/linux/omap3isp.h @@ -159,13 +159,25 @@ struct omap3isp_h3a_aewb_config { };
/**
- struct omap3isp_stat_data - Statistic data sent to or received from user
- @ts: Timestamp of returned framestats.
- @buf: Pointer to pass to user.
- struct omap3isp_stat_frame - Statistic data without timestamp nor pointer.
*/
- @buf_size: Size of buffer.
- @frame_number: Frame number of requested stats.
- @cur_frame: Current frame number being processed.
- @config_counter: Number of the configuration associated with the data.
+struct omap3isp_stat_frame {
- __u32 buf_size;
- __u16 frame_number;
- __u16 cur_frame;
- __u16 config_counter;
+};
+/**
- struct omap3isp_stat_data - Statistic data sent to or received from user
- @ts: Timestamp of returned framestats.
- @buf: Pointer to pass to user.
- @frame: Statistic data for frame.
- */
struct omap3isp_stat_data { #ifdef __KERNEL__ struct { @@ -176,10 +188,15 @@ struct omap3isp_stat_data { struct timeval ts; #endif void __user *buf;
- __u32 buf_size;
- __u16 frame_number;
- __u16 cur_frame;
- __u16 config_counter;
- union {
struct {__u32 buf_size;__u16 frame_number;__u16 cur_frame;__u16 config_counter;};struct omap3isp_stat_frame frame;- };
};
#ifdef __KERNEL__ @@ -189,10 +206,15 @@ struct omap3isp_stat_data_time32 { __s32 tv_usec; } ts; __u32 buf;
- __u32 buf_size;
- __u16 frame_number;
- __u16 cur_frame;
- __u16 config_counter;
- union {
struct {__u32 buf_size;__u16 frame_number;__u16 cur_frame;__u16 config_counter;};struct omap3isp_stat_frame frame;- };
}; #endif
-- 2.30.2