* [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays
@ 2020-05-27 14:11 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2020-05-27 14:11 UTC (permalink / raw)
To: Jeff Kirsher, David S. Miller, Jakub Kicinski
Cc: intel-wired-lan, netdev, linux-kernel, Gustavo A. R. Silva, Kees Cook
The current codebase makes use of one-element arrays in the following
form:
struct something {
int length;
u8 data[1];
};
struct something *instance;
instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
instance->length = size;
memcpy(instance->data, source, size);
but the preferred mechanism to declare variable-length types such as
these ones is a flexible array member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on. So, replace
the one-element array with a flexible-array member.
Also, make use of the offsetof() helper in order to simplify some macros
and properly calculate the size of the structures that contain
flexible-array members.
This issue was found with the help of Coccinelle and, audited _manually_.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v3:
- We still can simply the code even more by using offsetof() just once. :)
Changes in v2:
- Use offsetof(struct ice_aqc_sw_rules_elem, pdata) instead of
sizeof(struct ice_aqc_sw_rules_elem) - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata)
- Update changelog text.
.../net/ethernet/intel/ice/ice_adminq_cmd.h | 6 ++---
drivers/net/ethernet/intel/ice/ice_switch.c | 23 ++++++-------------
2 files changed, 10 insertions(+), 19 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
index 586d69491268a..faa21830e40d8 100644
--- a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
+++ b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
@@ -570,7 +570,7 @@ struct ice_sw_rule_lkup_rx_tx {
* lookup-type
*/
__le16 hdr_len;
- u8 hdr[1];
+ u8 hdr[];
} __packed;
/* Add/Update/Remove large action command/response entry
@@ -580,7 +580,7 @@ struct ice_sw_rule_lkup_rx_tx {
struct ice_sw_rule_lg_act {
__le16 index; /* Index in large action table */
__le16 size;
- __le32 act[1]; /* array of size for actions */
+ __le32 act[]; /* array of size for actions */
/* Max number of large actions */
#define ICE_MAX_LG_ACT 4
/* Bit 0:1 - Action type */
@@ -640,7 +640,7 @@ struct ice_sw_rule_lg_act {
struct ice_sw_rule_vsi_list {
__le16 index; /* Index of VSI/Prune list */
__le16 number_vsi;
- __le16 vsi[1]; /* Array of number_vsi VSI numbers */
+ __le16 vsi[]; /* Array of number_vsi VSI numbers */
};
/* Query VSI list command/response entry */
diff --git a/drivers/net/ethernet/intel/ice/ice_switch.c b/drivers/net/ethernet/intel/ice/ice_switch.c
index 0156b73df1b1f..191735ac491c6 100644
--- a/drivers/net/ethernet/intel/ice/ice_switch.c
+++ b/drivers/net/ethernet/intel/ice/ice_switch.c
@@ -29,25 +29,16 @@ static const u8 dummy_eth_header[DUMMY_ETH_HDR_LEN] = { 0x2, 0, 0, 0, 0, 0,
0x81, 0, 0, 0};
#define ICE_SW_RULE_RX_TX_ETH_HDR_SIZE \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lkup_rx_tx) + DUMMY_ETH_HDR_LEN - 1)
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx) + \
+ DUMMY_ETH_HDR_LEN)
#define ICE_SW_RULE_RX_TX_NO_HDR_SIZE \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lkup_rx_tx) - 1)
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx))
#define ICE_SW_RULE_LG_ACT_SIZE(n) \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lg_act) - \
- sizeof(((struct ice_sw_rule_lg_act *)0)->act) + \
- ((n) * sizeof(((struct ice_sw_rule_lg_act *)0)->act)))
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lg_act.act) + \
+ ((n) * sizeof(__le32)))
#define ICE_SW_RULE_VSI_LIST_SIZE(n) \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_vsi_list) - \
- sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi) + \
- ((n) * sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi)))
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.vsi_list.vsi) + \
+ ((n) * sizeof(__le16)))
/**
* ice_init_def_sw_recp - initialize the recipe book keeping tables
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Intel-wired-lan] [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays
@ 2020-05-27 14:11 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2020-05-27 14:11 UTC (permalink / raw)
To: intel-wired-lan
The current codebase makes use of one-element arrays in the following
form:
struct something {
int length;
u8 data[1];
};
struct something *instance;
instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
instance->length = size;
memcpy(instance->data, source, size);
but the preferred mechanism to declare variable-length types such as
these ones is a flexible array member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on. So, replace
the one-element array with a flexible-array member.
Also, make use of the offsetof() helper in order to simplify some macros
and properly calculate the size of the structures that contain
flexible-array members.
This issue was found with the help of Coccinelle and, audited _manually_.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v3:
- We still can simply the code even more by using offsetof() just once. :)
Changes in v2:
- Use offsetof(struct ice_aqc_sw_rules_elem, pdata) instead of
sizeof(struct ice_aqc_sw_rules_elem) - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata)
- Update changelog text.
.../net/ethernet/intel/ice/ice_adminq_cmd.h | 6 ++---
drivers/net/ethernet/intel/ice/ice_switch.c | 23 ++++++-------------
2 files changed, 10 insertions(+), 19 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
index 586d69491268a..faa21830e40d8 100644
--- a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
+++ b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h
@@ -570,7 +570,7 @@ struct ice_sw_rule_lkup_rx_tx {
* lookup-type
*/
__le16 hdr_len;
- u8 hdr[1];
+ u8 hdr[];
} __packed;
/* Add/Update/Remove large action command/response entry
@@ -580,7 +580,7 @@ struct ice_sw_rule_lkup_rx_tx {
struct ice_sw_rule_lg_act {
__le16 index; /* Index in large action table */
__le16 size;
- __le32 act[1]; /* array of size for actions */
+ __le32 act[]; /* array of size for actions */
/* Max number of large actions */
#define ICE_MAX_LG_ACT 4
/* Bit 0:1 - Action type */
@@ -640,7 +640,7 @@ struct ice_sw_rule_lg_act {
struct ice_sw_rule_vsi_list {
__le16 index; /* Index of VSI/Prune list */
__le16 number_vsi;
- __le16 vsi[1]; /* Array of number_vsi VSI numbers */
+ __le16 vsi[]; /* Array of number_vsi VSI numbers */
};
/* Query VSI list command/response entry */
diff --git a/drivers/net/ethernet/intel/ice/ice_switch.c b/drivers/net/ethernet/intel/ice/ice_switch.c
index 0156b73df1b1f..191735ac491c6 100644
--- a/drivers/net/ethernet/intel/ice/ice_switch.c
+++ b/drivers/net/ethernet/intel/ice/ice_switch.c
@@ -29,25 +29,16 @@ static const u8 dummy_eth_header[DUMMY_ETH_HDR_LEN] = { 0x2, 0, 0, 0, 0, 0,
0x81, 0, 0, 0};
#define ICE_SW_RULE_RX_TX_ETH_HDR_SIZE \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lkup_rx_tx) + DUMMY_ETH_HDR_LEN - 1)
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx) + \
+ DUMMY_ETH_HDR_LEN)
#define ICE_SW_RULE_RX_TX_NO_HDR_SIZE \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lkup_rx_tx) - 1)
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx))
#define ICE_SW_RULE_LG_ACT_SIZE(n) \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_lg_act) - \
- sizeof(((struct ice_sw_rule_lg_act *)0)->act) + \
- ((n) * sizeof(((struct ice_sw_rule_lg_act *)0)->act)))
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.lg_act.act) + \
+ ((n) * sizeof(__le32)))
#define ICE_SW_RULE_VSI_LIST_SIZE(n) \
- (sizeof(struct ice_aqc_sw_rules_elem) - \
- sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \
- sizeof(struct ice_sw_rule_vsi_list) - \
- sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi) + \
- ((n) * sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi)))
+ (offsetof(struct ice_aqc_sw_rules_elem, pdata.vsi_list.vsi) + \
+ ((n) * sizeof(__le16)))
/**
* ice_init_def_sw_recp - initialize the recipe book keeping tables
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* RE: [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays
2020-05-27 14:11 ` [Intel-wired-lan] " Gustavo A. R. Silva
@ 2020-05-29 5:35 ` Kirsher, Jeffrey T
-1 siblings, 0 replies; 4+ messages in thread
From: Kirsher, Jeffrey T @ 2020-05-29 5:35 UTC (permalink / raw)
To: Gustavo A. R. Silva, David S. Miller, Jakub Kicinski, Allan, Bruce W
Cc: intel-wired-lan, netdev, linux-kernel, Gustavo A. R. Silva, Kees Cook
> -----Original Message-----
> From: Gustavo A. R. Silva <gustavoars@kernel.org>
> Sent: Wednesday, May 27, 2020 07:11
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>; David S. Miller
> <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>
> Cc: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; Gustavo A. R. Silva <gustavo@embeddedor.com>;
> Kees Cook <keescook@chromium.org>
> Subject: [PATCH net-next v3] ice: Replace one-element arrays with flexible-
> arrays
>
> The current codebase makes use of one-element arrays in the following
> form:
>
> struct something {
> int length;
> u8 data[1];
> };
>
> struct something *instance;
>
> instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
> instance->length = size;
> memcpy(instance->data, source, size);
>
> but the preferred mechanism to declare variable-length types such as these
> ones is a flexible array member[1][2], introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning in case
> the flexible array does not occur last in the structure, which will help us prevent
> some kind of undefined behavior bugs from being inadvertently introduced[3]
> to the codebase from now on. So, replace the one-element array with a
> flexible-array member.
>
> Also, make use of the offsetof() helper in order to simplify some macros and
> properly calculate the size of the structures that contain flexible-array members.
>
> This issue was found with the help of Coccinelle and, audited _manually_.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
[Kirsher, Jeffrey T]
Thanks Gustavo, but we (or I should say Bruce Allan) already has a patch to resolve this,
and is a bit more thorough. I will make sure you get CC'd on the patch, for your review.
> ---
> Changes in v3:
> - We still can simply the code even more by using offsetof() just once. :)
>
> Changes in v2:
> - Use offsetof(struct ice_aqc_sw_rules_elem, pdata) instead of
> sizeof(struct ice_aqc_sw_rules_elem) - sizeof(((struct ice_aqc_sw_rules_elem
> *)0)->pdata)
> - Update changelog text.
>
> .../net/ethernet/intel/ice/ice_adminq_cmd.h | 6 ++---
> drivers/net/ethernet/intel/ice/ice_switch.c | 23 ++++++-------------
> 2 files changed, 10 insertions(+), 19 deletions(-)
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Intel-wired-lan] [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays
@ 2020-05-29 5:35 ` Kirsher, Jeffrey T
0 siblings, 0 replies; 4+ messages in thread
From: Kirsher, Jeffrey T @ 2020-05-29 5:35 UTC (permalink / raw)
To: intel-wired-lan
> -----Original Message-----
> From: Gustavo A. R. Silva <gustavoars@kernel.org>
> Sent: Wednesday, May 27, 2020 07:11
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>; David S. Miller
> <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>
> Cc: intel-wired-lan at lists.osuosl.org; netdev at vger.kernel.org; linux-
> kernel at vger.kernel.org; Gustavo A. R. Silva <gustavo@embeddedor.com>;
> Kees Cook <keescook@chromium.org>
> Subject: [PATCH net-next v3] ice: Replace one-element arrays with flexible-
> arrays
>
> The current codebase makes use of one-element arrays in the following
> form:
>
> struct something {
> int length;
> u8 data[1];
> };
>
> struct something *instance;
>
> instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
> instance->length = size;
> memcpy(instance->data, source, size);
>
> but the preferred mechanism to declare variable-length types such as these
> ones is a flexible array member[1][2], introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning in case
> the flexible array does not occur last in the structure, which will help us prevent
> some kind of undefined behavior bugs from being inadvertently introduced[3]
> to the codebase from now on. So, replace the one-element array with a
> flexible-array member.
>
> Also, make use of the offsetof() helper in order to simplify some macros and
> properly calculate the size of the structures that contain flexible-array members.
>
> This issue was found with the help of Coccinelle and, audited _manually_.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
[Kirsher, Jeffrey T]
Thanks Gustavo, but we (or I should say Bruce Allan) already has a patch to resolve this,
and is a bit more thorough. I will make sure you get CC'd on the patch, for your review.
> ---
> Changes in v3:
> - We still can simply the code even more by using offsetof() just once. :)
>
> Changes in v2:
> - Use offsetof(struct ice_aqc_sw_rules_elem, pdata) instead of
> sizeof(struct ice_aqc_sw_rules_elem) - sizeof(((struct ice_aqc_sw_rules_elem
> *)0)->pdata)
> - Update changelog text.
>
> .../net/ethernet/intel/ice/ice_adminq_cmd.h | 6 ++---
> drivers/net/ethernet/intel/ice/ice_switch.c | 23 ++++++-------------
> 2 files changed, 10 insertions(+), 19 deletions(-)
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-05-29 5:35 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-27 14:11 [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays Gustavo A. R. Silva
2020-05-27 14:11 ` [Intel-wired-lan] " Gustavo A. R. Silva
2020-05-29 5:35 ` Kirsher, Jeffrey T
2020-05-29 5:35 ` [Intel-wired-lan] " Kirsher, Jeffrey T
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