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media: omap3isp: Use struct_group() for memcpy() region

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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.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: linux-media@vger.kernel.org
Fixes: 378e3f81cb ("media: omap3isp: support 64-bit version of omap3isp_stat_data")
Cc: stable@vger.kernel.org
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/20211215220505.GB21862@embeddedor
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2021-05-24 21:15:15 -07:00
parent e52432e164
commit fad278388e
2 changed files with 16 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/media/platform/omap3isp/ispstat.c
View file

@ -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;
}

21
include/uapi/linux/omap3isp.h
View file

@ -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 tag */, 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 tag */, frame, /* no attrs */,
__u32 buf_size;
__u16 frame_number;
__u16 cur_frame;
__u16 config_counter;
);
};
#endif