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[v2,next] Bluetooth: hci_conn: Use __counted_by() in struct hci_cp_le_big_create_sync and avoid -Wfamnae warning

Message ID ZivaHUQyDDK9fXEk@neat (mailing list archive)
State Accepted
Commit b4208ba1661e05a39d436201514bc92e194ca709
Headers show
Series [v2,next] Bluetooth: hci_conn: Use __counted_by() in struct hci_cp_le_big_create_sync and avoid -Wfamnae warning | expand

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tedd_an/CheckSmatch fail CheckSparse: FAIL: Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: net/bluetooth/hci_core.o] Error 139 make[4]: *** Deleting file 'net/bluetooth/hci_core.o' make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2 make[2]: *** [scripts/Makefile.build:485: net] Error 2 make[2]: *** Waiting for unfinished jobs.... Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bcm203x.o] Error 139 make[4]: *** Deleting file 'drivers/bluetooth/bcm203x.o' make[4]: *** Waiting for unfinished jobs.... Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bpa10x.o] Error 139 make[4]: *** Deleting file 'drivers/bluetooth/bpa10x.o' make[3]: *** [scripts/Makefile.build:485: drivers/bluetooth] Error 2 make[2]: *** [scripts/Makefile.build:485: drivers] Error 2 make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2 make: *** [Makefile:240: __sub-make] Error 2
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Commit Message

Gustavo A. R. Silva April 26, 2024, 4:45 p.m. UTC
Prepare for the coming implementation by GCC and Clang of the
__counted_by attribute. Flexible array members annotated with
__counted_by can have their accesses bounds-checked at run-time
via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE
(for strcpy/memcpy-family functions).

Also, -Wflex-array-member-not-at-end is coming in GCC-14, and we are
getting ready to enable it globally.

So, use the `DEFINE_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

With these changes, fix the following warning:
net/bluetooth/hci_conn.c:2116:50: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
 - Use `sizeof(*pdu) + num_bis` instead of `__struct_size(pdu)`

v1:
 - Link: https://lore.kernel.org/linux-hardening/ZivYcpzZsc7aIFZ5@neat/

 include/net/bluetooth/hci.h |  2 +-
 net/bluetooth/hci_conn.c    | 26 +++++++++++---------------
 2 files changed, 12 insertions(+), 16 deletions(-)

Comments

Kees Cook April 26, 2024, 5:25 p.m. UTC | #1
On Fri, Apr 26, 2024 at 10:45:17AM -0600, Gustavo A. R. Silva wrote:
> Prepare for the coming implementation by GCC and Clang of the
> __counted_by attribute. Flexible array members annotated with
> __counted_by can have their accesses bounds-checked at run-time
> via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE
> (for strcpy/memcpy-family functions).
> 
> Also, -Wflex-array-member-not-at-end is coming in GCC-14, and we are
> getting ready to enable it globally.
> 
> So, use the `DEFINE_FLEX()` helper for an on-stack definition of
> a flexible structure where the size of the flexible-array member
> is known at compile-time, and refactor the rest of the code,
> accordingly.
> 
> With these changes, fix the following warning:
> net/bluetooth/hci_conn.c:2116:50: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Link: https://github.com/KSPP/linux/issues/202
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Looks right to me. Yay for DEFINE_FLEX(). :)

Reviewed-by: Kees Cook <keescook@chromium.org>
patchwork-bot+bluetooth@kernel.org April 29, 2024, 6:20 p.m. UTC | #2
Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Fri, 26 Apr 2024 10:45:17 -0600 you wrote:
> Prepare for the coming implementation by GCC and Clang of the
> __counted_by attribute. Flexible array members annotated with
> __counted_by can have their accesses bounds-checked at run-time
> via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE
> (for strcpy/memcpy-family functions).
> 
> Also, -Wflex-array-member-not-at-end is coming in GCC-14, and we are
> getting ready to enable it globally.
> 
> [...]

Here is the summary with links:
  - [v2,next] Bluetooth: hci_conn: Use __counted_by() in struct hci_cp_le_big_create_sync and avoid -Wfamnae warning
    https://git.kernel.org/bluetooth/bluetooth-next/c/b4208ba1661e

You are awesome, thank you!
diff mbox series

Patch

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 5c12761cbc0e..fe23e862921d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2216,7 +2216,7 @@  struct hci_cp_le_big_create_sync {
 	__u8    mse;
 	__le16  timeout;
 	__u8    num_bis;
-	__u8    bis[];
+	__u8    bis[] __counted_by(num_bis);
 } __packed;
 
 #define HCI_OP_LE_BIG_TERM_SYNC			0x206c
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 81166a5bc034..d6daf55f0307 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -2112,13 +2112,10 @@  int hci_le_big_create_sync(struct hci_dev *hdev, struct hci_conn *hcon,
 			   struct bt_iso_qos *qos,
 			   __u16 sync_handle, __u8 num_bis, __u8 bis[])
 {
-	struct _packed {
-		struct hci_cp_le_big_create_sync cp;
-		__u8  bis[0x11];
-	} pdu;
+	DEFINE_FLEX(struct hci_cp_le_big_create_sync, pdu, bis, num_bis, 0x11);
 	int err;
 
-	if (num_bis < 0x01 || num_bis > sizeof(pdu.bis))
+	if (num_bis < 0x01 || num_bis > pdu->num_bis)
 		return -EINVAL;
 
 	err = qos_set_big(hdev, qos);
@@ -2128,18 +2125,17 @@  int hci_le_big_create_sync(struct hci_dev *hdev, struct hci_conn *hcon,
 	if (hcon)
 		hcon->iso_qos.bcast.big = qos->bcast.big;
 
-	memset(&pdu, 0, sizeof(pdu));
-	pdu.cp.handle = qos->bcast.big;
-	pdu.cp.sync_handle = cpu_to_le16(sync_handle);
-	pdu.cp.encryption = qos->bcast.encryption;
-	memcpy(pdu.cp.bcode, qos->bcast.bcode, sizeof(pdu.cp.bcode));
-	pdu.cp.mse = qos->bcast.mse;
-	pdu.cp.timeout = cpu_to_le16(qos->bcast.timeout);
-	pdu.cp.num_bis = num_bis;
-	memcpy(pdu.bis, bis, num_bis);
+	pdu->handle = qos->bcast.big;
+	pdu->sync_handle = cpu_to_le16(sync_handle);
+	pdu->encryption = qos->bcast.encryption;
+	memcpy(pdu->bcode, qos->bcast.bcode, sizeof(pdu->bcode));
+	pdu->mse = qos->bcast.mse;
+	pdu->timeout = cpu_to_le16(qos->bcast.timeout);
+	pdu->num_bis = num_bis;
+	memcpy(pdu->bis, bis, num_bis);
 
 	return hci_send_cmd(hdev, HCI_OP_LE_BIG_CREATE_SYNC,
-			    sizeof(pdu.cp) + num_bis, &pdu);
+			    sizeof(*pdu) + num_bis, pdu);
 }
 
 static void create_big_complete(struct hci_dev *hdev, void *data, int err)