[PATCH v2 23/63] media: omap3isp: Use struct_group() for memcpy() region
From: Kees Cook <hidden>
Date: 2021-08-18 06:09:00
Also in:
dri-devel, linux-hardening, linux-kbuild, linux-staging, linux-wireless, lkml, netdev
Subsystem:
media input infrastructure (v4l/dvb), the rest · Maintainers:
Mauro Carvalho Chehab, Linus Torvalds
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 struct_group(). 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 <redacted>
---
drivers/media/platform/omap3isp/ispstat.c | 5 +++--
include/uapi/linux/omap3isp.h | 21 +++++++++++++--------
2 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/media/platform/omap3isp/ispstat.c b/drivers/media/platform/omap3isp/ispstat.c
index 5b9b57f4d9bf..68cf68dbcace 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.frame, sizeof(data->frame)); return 0; }
diff --git a/include/uapi/linux/omap3isp.h b/include/uapi/linux/omap3isp.h
index 87b55755f4ff..9a6b3ed11455 100644
--- a/include/uapi/linux/omap3isp.h
+++ b/include/uapi/linux/omap3isp.h@@ -162,6 +162,7 @@ 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. + * @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.
@@ -176,10 +177,12 @@ struct omap3isp_stat_data { struct timeval ts; #endif void __user *buf; - __u32 buf_size; - __u16 frame_number; - __u16 cur_frame; - __u16 config_counter; + __struct_group(/* no type */, frame, /* no attrs */, + __u32 buf_size; + __u16 frame_number; + __u16 cur_frame; + __u16 config_counter; + ); }; #ifdef __KERNEL__
@@ -189,10 +192,12 @@ struct omap3isp_stat_data_time32 { __s32 tv_usec; } ts; __u32 buf; - __u32 buf_size; - __u16 frame_number; - __u16 cur_frame; - __u16 config_counter; + __struct_group(/* no type */, frame, /* no attrs */, + __u32 buf_size; + __u16 frame_number; + __u16 cur_frame; + __u16 config_counter; + ); }; #endif
--
2.30.2