Re: [PATCH] media: meson: vdec: potential dereference of null pointer
From: Neil Armstrong <hidden>
Date: 2021-12-09 17:52:19
Also in:
linux-amlogic, linux-arm-kernel, linux-media, lkml
Subsystem:
media input infrastructure (v4l/dvb), meson video decoder driver for amlogic socs, staging subsystem, the rest · Maintainers:
Mauro Carvalho Chehab, Neil Armstrong, Greg Kroah-Hartman, Linus Torvalds
Hi, On 09/12/2021 12:58, Hans Verkuil wrote:
On 09/12/2021 09:58, Jiasheng Jiang wrote:quoted
he return value of kzalloc() needs to be checked. To avoid use of null pointer in case of the failure of alloc. Fixes: 876f123b8956 ("media: meson: vdec: bring up to compliance") Signed-off-by: Jiasheng Jiang <redacted> --- drivers/staging/media/meson/vdec/vdec_helpers.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.c b/drivers/staging/media/meson/vdec/vdec_helpers.c index 7f07a9175815..025885fcfec6 100644 --- a/drivers/staging/media/meson/vdec/vdec_helpers.c +++ b/drivers/staging/media/meson/vdec/vdec_helpers.c@@ -234,6 +234,8 @@ void amvdec_add_ts(struct amvdec_session *sess, u64 ts, unsigned long flags; new_ts = kzalloc(sizeof(*new_ts), GFP_KERNEL); + if (!new_ts) + return;While this avoids dereferencing a NULL pointer, this error isn't propagated to the caller. And I'm not sure if that's right. Neil, what should be done in this case? Regards, Hansquoted
new_ts->ts = ts; new_ts->tc = tc; new_ts->offset = offset;
Probably something like this: ===================><=============================
diff --git a/drivers/staging/media/meson/vdec/esparser.c b/drivers/staging/media/meson/vdec/esparser.c
index db7022707ff8..df733eff9ac7 100644
--- a/drivers/staging/media/meson/vdec/esparser.c
+++ b/drivers/staging/media/meson/vdec/esparser.c@@ -328,7 +328,11 @@ esparser_queue(struct amvdec_session *sess, struct vb2_v4l2_buffer *vbuf) offset = esparser_get_offset(sess); - amvdec_add_ts(sess, vb->timestamp, vbuf->timecode, offset, vbuf->flags); + ret = amvdec_add_ts(sess, vb->timestamp, vbuf->timecode, offset, vbuf->flags); + if (ret) { + v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_ERROR); + return ret; + } dev_dbg(core->dev, "esparser: ts = %llu pld_size = %u offset = %08X flags = %08X\n", vb->timestamp, payload_size, offset, vbuf->flags);
diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.c b/drivers/staging/media/meson/vdec/vdec_helpers.c
index b9125c295d1d..593b2ccbece2 100644
--- a/drivers/staging/media/meson/vdec/vdec_helpers.c
+++ b/drivers/staging/media/meson/vdec/vdec_helpers.c@@ -227,13 +227,15 @@ int amvdec_set_canvases(struct amvdec_session *sess, } EXPORT_SYMBOL_GPL(amvdec_set_canvases); -void amvdec_add_ts(struct amvdec_session *sess, u64 ts, - struct v4l2_timecode tc, u32 offset, u32 vbuf_flags) +int amvdec_add_ts(struct amvdec_session *sess, u64 ts, + struct v4l2_timecode tc, u32 offset, u32 vbuf_flags) { struct amvdec_timestamp *new_ts; unsigned long flags; new_ts = kzalloc(sizeof(*new_ts), GFP_KERNEL); + if (!new_ts) + return -ENOMEM; new_ts->ts = ts; new_ts->tc = tc; new_ts->offset = offset;
diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.h b/drivers/staging/media/meson/vdec/vdec_helpers.h
index 88137d15aa3a..4bf3e61d081b 100644
--- a/drivers/staging/media/meson/vdec/vdec_helpers.h
+++ b/drivers/staging/media/meson/vdec/vdec_helpers.h@@ -56,8 +56,8 @@ void amvdec_dst_buf_done_offset(struct amvdec_session *sess, * @offset: offset in the VIFIFO where the associated packet was written * @flags: the vb2_v4l2_buffer flags */ -void amvdec_add_ts(struct amvdec_session *sess, u64 ts, - struct v4l2_timecode tc, u32 offset, u32 flags); +int amvdec_add_ts(struct amvdec_session *sess, u64 ts, + struct v4l2_timecode tc, u32 offset, u32 flags); void amvdec_remove_ts(struct amvdec_session *sess, u64 ts); /**