2021-06-04 00:44:59

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH v2][next] media: venus: hfi_msgs.h: Replace one-element arrays with flexible-array members

There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Use flexible-array members in struct hfi_msg_sys_property_info_pkt and
hfi_msg_session_property_info_pkt instead of one-element arrays, and
refactor the code accordingly.

Also, this helps with the ongoing efforts to enable -Warray-bounds by
fixing the following warnings:

CC [M] drivers/media/platform/qcom/venus/hfi_msgs.o
drivers/media/platform/qcom/venus/hfi_msgs.c: In function ‘hfi_sys_property_info’:
drivers/media/platform/qcom/venus/hfi_msgs.c:246:35: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
246 | if (req_bytes < 128 || !pkt->data[1] || pkt->num_properties > 1)
| ~~~~~~~~~^~~
drivers/media/platform/qcom/venus/hfi_msgs.c: In function ‘hfi_session_prop_info’:
drivers/media/platform/qcom/venus/hfi_msgs.c:342:62: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
342 | if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[1])
| ~~~~~~~~~^~~

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Co-developed-by: Kees Cook <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
Changes in v2:
- Fix packet size calculation by adding member _property_ to
both structutures hfi_msg_sys_property_info_pkt and
hfi_msg_session_property_info_pkt, and refactor the code
accordingly.

JFYI: We are about to be able to globally enable -Warray-bounds and,
these are pretty much the last out-of-bounds warnings in linux-next. :)

drivers/media/platform/qcom/venus/hfi_msgs.c | 16 ++++++++--------
drivers/media/platform/qcom/venus/hfi_msgs.h | 6 ++++--
2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/hfi_msgs.c b/drivers/media/platform/qcom/venus/hfi_msgs.c
index a2d436d407b2..d9fde66f6fa8 100644
--- a/drivers/media/platform/qcom/venus/hfi_msgs.c
+++ b/drivers/media/platform/qcom/venus/hfi_msgs.c
@@ -251,11 +251,11 @@ sys_get_prop_image_version(struct device *dev,

req_bytes = pkt->hdr.size - sizeof(*pkt);

- if (req_bytes < VER_STR_SZ || !pkt->data[1] || pkt->num_properties > 1)
+ if (req_bytes < VER_STR_SZ || !pkt->data[0] || pkt->num_properties > 1)
/* bad packet */
return;

- img_ver = (u8 *)&pkt->data[1];
+ img_ver = pkt->data;

dev_dbg(dev, VDBGL "F/W version: %s\n", img_ver);

@@ -277,7 +277,7 @@ static void hfi_sys_property_info(struct venus_core *core,
return;
}

- switch (pkt->data[0]) {
+ switch (pkt->property) {
case HFI_PROPERTY_SYS_IMAGE_VERSION:
sys_get_prop_image_version(dev, pkt);
break;
@@ -338,7 +338,7 @@ session_get_prop_profile_level(struct hfi_msg_session_property_info_pkt *pkt,
/* bad packet */
return HFI_ERR_SESSION_INVALID_PARAMETER;

- hfi = (struct hfi_profile_level *)&pkt->data[1];
+ hfi = (struct hfi_profile_level *)&pkt->data[0];
profile_level->profile = hfi->profile;
profile_level->level = hfi->level;

@@ -355,11 +355,11 @@ session_get_prop_buf_req(struct hfi_msg_session_property_info_pkt *pkt,

req_bytes = pkt->shdr.hdr.size - sizeof(*pkt);

- if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[1])
+ if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[0])
/* bad packet */
return HFI_ERR_SESSION_INVALID_PARAMETER;

- buf_req = (struct hfi_buffer_requirements *)&pkt->data[1];
+ buf_req = (struct hfi_buffer_requirements *)&pkt->data[0];
if (!buf_req)
return HFI_ERR_SESSION_INVALID_PARAMETER;

@@ -391,7 +391,7 @@ static void hfi_session_prop_info(struct venus_core *core,
goto done;
}

- switch (pkt->data[0]) {
+ switch (pkt->property) {
case HFI_PROPERTY_CONFIG_BUFFER_REQUIREMENTS:
memset(hprop->bufreq, 0, sizeof(hprop->bufreq));
error = session_get_prop_buf_req(pkt, hprop->bufreq);
@@ -404,7 +404,7 @@ static void hfi_session_prop_info(struct venus_core *core,
case HFI_PROPERTY_CONFIG_VDEC_ENTROPY:
break;
default:
- dev_dbg(dev, VDBGM "unknown property id:%x\n", pkt->data[0]);
+ dev_dbg(dev, VDBGM "unknown property id:%x\n", pkt->property);
return;
}

diff --git a/drivers/media/platform/qcom/venus/hfi_msgs.h b/drivers/media/platform/qcom/venus/hfi_msgs.h
index 526d9f5b487b..510513697335 100644
--- a/drivers/media/platform/qcom/venus/hfi_msgs.h
+++ b/drivers/media/platform/qcom/venus/hfi_msgs.h
@@ -113,7 +113,8 @@ struct hfi_msg_sys_ping_ack_pkt {
struct hfi_msg_sys_property_info_pkt {
struct hfi_pkt_hdr hdr;
u32 num_properties;
- u32 data[1];
+ u32 property;
+ u8 data[];
};

struct hfi_msg_session_load_resources_done_pkt {
@@ -233,7 +234,8 @@ struct hfi_msg_session_parse_sequence_header_done_pkt {
struct hfi_msg_session_property_info_pkt {
struct hfi_session_hdr_pkt shdr;
u32 num_properties;
- u32 data[1];
+ u32 property;
+ u8 data[];
};

struct hfi_msg_session_release_resources_done_pkt {
--
2.27.0


2021-06-09 21:08:23

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH v2][next] media: venus: hfi_msgs.h: Replace one-element arrays with flexible-array members

Hi all,

Friendly ping: who can take this, please?

Thanks
--
Gustavo

On 6/3/21 19:43, Gustavo A. R. Silva wrote:
> There is a regular need in the kernel to provide a way to declare having
> a dynamically sized set of trailing elements in a structure. Kernel code
> should always use “flexible array members”[1] for these cases. The older
> style of one-element or zero-length arrays should no longer be used[2].
>
> Use flexible-array members in struct hfi_msg_sys_property_info_pkt and
> hfi_msg_session_property_info_pkt instead of one-element arrays, and
> refactor the code accordingly.
>
> Also, this helps with the ongoing efforts to enable -Warray-bounds by
> fixing the following warnings:
>
> CC [M] drivers/media/platform/qcom/venus/hfi_msgs.o
> drivers/media/platform/qcom/venus/hfi_msgs.c: In function ‘hfi_sys_property_info’:
> drivers/media/platform/qcom/venus/hfi_msgs.c:246:35: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
> 246 | if (req_bytes < 128 || !pkt->data[1] || pkt->num_properties > 1)
> | ~~~~~~~~~^~~
> drivers/media/platform/qcom/venus/hfi_msgs.c: In function ‘hfi_session_prop_info’:
> drivers/media/platform/qcom/venus/hfi_msgs.c:342:62: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
> 342 | if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[1])
> | ~~~~~~~~~^~~
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/109
> Co-developed-by: Kees Cook <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> Changes in v2:
> - Fix packet size calculation by adding member _property_ to
> both structutures hfi_msg_sys_property_info_pkt and
> hfi_msg_session_property_info_pkt, and refactor the code
> accordingly.
>
> JFYI: We are about to be able to globally enable -Warray-bounds and,
> these are pretty much the last out-of-bounds warnings in linux-next. :)
>
> drivers/media/platform/qcom/venus/hfi_msgs.c | 16 ++++++++--------
> drivers/media/platform/qcom/venus/hfi_msgs.h | 6 ++++--
> 2 files changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/venus/hfi_msgs.c b/drivers/media/platform/qcom/venus/hfi_msgs.c
> index a2d436d407b2..d9fde66f6fa8 100644
> --- a/drivers/media/platform/qcom/venus/hfi_msgs.c
> +++ b/drivers/media/platform/qcom/venus/hfi_msgs.c
> @@ -251,11 +251,11 @@ sys_get_prop_image_version(struct device *dev,
>
> req_bytes = pkt->hdr.size - sizeof(*pkt);
>
> - if (req_bytes < VER_STR_SZ || !pkt->data[1] || pkt->num_properties > 1)
> + if (req_bytes < VER_STR_SZ || !pkt->data[0] || pkt->num_properties > 1)
> /* bad packet */
> return;
>
> - img_ver = (u8 *)&pkt->data[1];
> + img_ver = pkt->data;
>
> dev_dbg(dev, VDBGL "F/W version: %s\n", img_ver);
>
> @@ -277,7 +277,7 @@ static void hfi_sys_property_info(struct venus_core *core,
> return;
> }
>
> - switch (pkt->data[0]) {
> + switch (pkt->property) {
> case HFI_PROPERTY_SYS_IMAGE_VERSION:
> sys_get_prop_image_version(dev, pkt);
> break;
> @@ -338,7 +338,7 @@ session_get_prop_profile_level(struct hfi_msg_session_property_info_pkt *pkt,
> /* bad packet */
> return HFI_ERR_SESSION_INVALID_PARAMETER;
>
> - hfi = (struct hfi_profile_level *)&pkt->data[1];
> + hfi = (struct hfi_profile_level *)&pkt->data[0];
> profile_level->profile = hfi->profile;
> profile_level->level = hfi->level;
>
> @@ -355,11 +355,11 @@ session_get_prop_buf_req(struct hfi_msg_session_property_info_pkt *pkt,
>
> req_bytes = pkt->shdr.hdr.size - sizeof(*pkt);
>
> - if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[1])
> + if (!req_bytes || req_bytes % sizeof(*buf_req) || !pkt->data[0])
> /* bad packet */
> return HFI_ERR_SESSION_INVALID_PARAMETER;
>
> - buf_req = (struct hfi_buffer_requirements *)&pkt->data[1];
> + buf_req = (struct hfi_buffer_requirements *)&pkt->data[0];
> if (!buf_req)
> return HFI_ERR_SESSION_INVALID_PARAMETER;
>
> @@ -391,7 +391,7 @@ static void hfi_session_prop_info(struct venus_core *core,
> goto done;
> }
>
> - switch (pkt->data[0]) {
> + switch (pkt->property) {
> case HFI_PROPERTY_CONFIG_BUFFER_REQUIREMENTS:
> memset(hprop->bufreq, 0, sizeof(hprop->bufreq));
> error = session_get_prop_buf_req(pkt, hprop->bufreq);
> @@ -404,7 +404,7 @@ static void hfi_session_prop_info(struct venus_core *core,
> case HFI_PROPERTY_CONFIG_VDEC_ENTROPY:
> break;
> default:
> - dev_dbg(dev, VDBGM "unknown property id:%x\n", pkt->data[0]);
> + dev_dbg(dev, VDBGM "unknown property id:%x\n", pkt->property);
> return;
> }
>
> diff --git a/drivers/media/platform/qcom/venus/hfi_msgs.h b/drivers/media/platform/qcom/venus/hfi_msgs.h
> index 526d9f5b487b..510513697335 100644
> --- a/drivers/media/platform/qcom/venus/hfi_msgs.h
> +++ b/drivers/media/platform/qcom/venus/hfi_msgs.h
> @@ -113,7 +113,8 @@ struct hfi_msg_sys_ping_ack_pkt {
> struct hfi_msg_sys_property_info_pkt {
> struct hfi_pkt_hdr hdr;
> u32 num_properties;
> - u32 data[1];
> + u32 property;
> + u8 data[];
> };
>
> struct hfi_msg_session_load_resources_done_pkt {
> @@ -233,7 +234,8 @@ struct hfi_msg_session_parse_sequence_header_done_pkt {
> struct hfi_msg_session_property_info_pkt {
> struct hfi_session_hdr_pkt shdr;
> u32 num_properties;
> - u32 data[1];
> + u32 property;
> + u8 data[];
> };
>
> struct hfi_msg_session_release_resources_done_pkt {
>