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Subject[PATCH] media: v4l2-ioctl: fix function types for IOCTL_INFO_STD
Date
This change fixes indirect call mismatches with Control-Flow Integrity
checking, which are caused by calling standard ioctls using a function
pointer that doesn't match the type of the actual function.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
drivers/media/v4l2-core/v4l2-ioctl.c | 72 ++++++++++++++++++----------
1 file changed, 46 insertions(+), 26 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index f48c505550e0..d50a06ab3509 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2489,11 +2489,8 @@ struct v4l2_ioctl_info {
unsigned int ioctl;
u32 flags;
const char * const name;
- union {
- u32 offset;
- int (*func)(const struct v4l2_ioctl_ops *ops,
- struct file *file, void *fh, void *p);
- } u;
+ int (*func)(const struct v4l2_ioctl_ops *ops, struct file *file,
+ void *fh, void *p);
void (*debug)(const void *arg, bool write_only);
};

@@ -2501,27 +2498,24 @@ struct v4l2_ioctl_info {
#define INFO_FL_PRIO (1 << 0)
/* This control can be valid if the filehandle passes a control handler. */
#define INFO_FL_CTRL (1 << 1)
-/* This is a standard ioctl, no need for special code */
-#define INFO_FL_STD (1 << 2)
/* This is ioctl has its own function */
-#define INFO_FL_FUNC (1 << 3)
+#define INFO_FL_FUNC (1 << 2)
/* Queuing ioctl */
-#define INFO_FL_QUEUE (1 << 4)
+#define INFO_FL_QUEUE (1 << 3)
/* Always copy back result, even on error */
-#define INFO_FL_ALWAYS_COPY (1 << 5)
+#define INFO_FL_ALWAYS_COPY (1 << 4)
/* Zero struct from after the field to the end */
#define INFO_FL_CLEAR(v4l2_struct, field) \
((offsetof(struct v4l2_struct, field) + \
sizeof(((struct v4l2_struct *)0)->field)) << 16)
#define INFO_FL_CLEAR_MASK (_IOC_SIZEMASK << 16)

-#define IOCTL_INFO_STD(_ioctl, _vidioc, _debug, _flags) \
- [_IOC_NR(_ioctl)] = { \
- .ioctl = _ioctl, \
- .flags = _flags | INFO_FL_STD, \
- .name = #_ioctl, \
- .u.offset = offsetof(struct v4l2_ioctl_ops, _vidioc), \
- .debug = _debug, \
+#define DEFINE_IOCTL_STD_FNC(_vidioc) \
+ static int __v4l_ ## _vidioc ## _fnc( \
+ const struct v4l2_ioctl_ops *ops, \
+ struct file *file, void *fh, void *p) \
+ { \
+ return ops->_vidioc(file, fh, p); \
}

#define IOCTL_INFO_FNC(_ioctl, _func, _debug, _flags) \
@@ -2529,10 +2523,42 @@ struct v4l2_ioctl_info {
.ioctl = _ioctl, \
.flags = _flags | INFO_FL_FUNC, \
.name = #_ioctl, \
- .u.func = _func, \
+ .func = _func, \
.debug = _debug, \
}

+#define IOCTL_INFO_STD(_ioctl, _vidioc, _debug, _flags) \
+ IOCTL_INFO_FNC(_ioctl, __v4l_ ## _vidioc ## _fnc, _debug, _flags)
+
+DEFINE_IOCTL_STD_FNC(vidioc_g_fbuf)
+DEFINE_IOCTL_STD_FNC(vidioc_s_fbuf)
+DEFINE_IOCTL_STD_FNC(vidioc_expbuf)
+DEFINE_IOCTL_STD_FNC(vidioc_g_std)
+DEFINE_IOCTL_STD_FNC(vidioc_g_audio)
+DEFINE_IOCTL_STD_FNC(vidioc_s_audio)
+DEFINE_IOCTL_STD_FNC(vidioc_g_input)
+DEFINE_IOCTL_STD_FNC(vidioc_g_edid)
+DEFINE_IOCTL_STD_FNC(vidioc_s_edid)
+DEFINE_IOCTL_STD_FNC(vidioc_g_output)
+DEFINE_IOCTL_STD_FNC(vidioc_g_audout)
+DEFINE_IOCTL_STD_FNC(vidioc_s_audout)
+DEFINE_IOCTL_STD_FNC(vidioc_g_jpegcomp)
+DEFINE_IOCTL_STD_FNC(vidioc_s_jpegcomp)
+DEFINE_IOCTL_STD_FNC(vidioc_enumaudio)
+DEFINE_IOCTL_STD_FNC(vidioc_enumaudout)
+DEFINE_IOCTL_STD_FNC(vidioc_enum_framesizes)
+DEFINE_IOCTL_STD_FNC(vidioc_enum_frameintervals)
+DEFINE_IOCTL_STD_FNC(vidioc_g_enc_index)
+DEFINE_IOCTL_STD_FNC(vidioc_encoder_cmd)
+DEFINE_IOCTL_STD_FNC(vidioc_try_encoder_cmd)
+DEFINE_IOCTL_STD_FNC(vidioc_decoder_cmd)
+DEFINE_IOCTL_STD_FNC(vidioc_try_decoder_cmd)
+DEFINE_IOCTL_STD_FNC(vidioc_s_dv_timings)
+DEFINE_IOCTL_STD_FNC(vidioc_g_dv_timings)
+DEFINE_IOCTL_STD_FNC(vidioc_enum_dv_timings)
+DEFINE_IOCTL_STD_FNC(vidioc_query_dv_timings)
+DEFINE_IOCTL_STD_FNC(vidioc_dv_timings_cap)
+
static struct v4l2_ioctl_info v4l2_ioctls[] = {
IOCTL_INFO_FNC(VIDIOC_QUERYCAP, v4l_querycap, v4l_print_querycap, 0),
IOCTL_INFO_FNC(VIDIOC_ENUM_FMT, v4l_enum_fmt, v4l_print_fmtdesc, INFO_FL_CLEAR(v4l2_fmtdesc, type)),
@@ -2717,14 +2743,8 @@ static long __video_do_ioctl(struct file *file,
}

write_only = _IOC_DIR(cmd) == _IOC_WRITE;
- if (info->flags & INFO_FL_STD) {
- typedef int (*vidioc_op)(struct file *file, void *fh, void *p);
- const void *p = vfd->ioctl_ops;
- const vidioc_op *vidioc = p + info->u.offset;
-
- ret = (*vidioc)(file, fh, arg);
- } else if (info->flags & INFO_FL_FUNC) {
- ret = info->u.func(ops, file, fh, arg);
+ if (info->flags & INFO_FL_FUNC) {
+ ret = info->func(ops, file, fh, arg);
} else if (!ops->vidioc_default) {
ret = -ENOTTY;
} else {
--
2.17.0.441.gb46fe60e1d-goog
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