diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 16:20:17 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 21:24:51 +0300 |
| commit | 6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch) | |
| tree | 3ce2cf2b7886400097251d33c05435653bcafe9b /drivers/usb/serial | |
| parent | 2f41c8a25feb822203f92e17f3720397805d0cfd (diff) | |
| download | linux-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.xz | |
USB: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, 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.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[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 <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial')
| -rw-r--r-- | drivers/usb/serial/io_usbvend.h | 4 | ||||
| -rw-r--r-- | drivers/usb/serial/ti_usb_3410_5052.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/drivers/usb/serial/io_usbvend.h b/drivers/usb/serial/io_usbvend.h index c38e87ac5ea9..0d1a5bb4636e 100644 --- a/drivers/usb/serial/io_usbvend.h +++ b/drivers/usb/serial/io_usbvend.h @@ -593,7 +593,7 @@ struct ti_i2c_desc { __u8 Type; // Type of descriptor __le16 Size; // Size of data only not including header __u8 CheckSum; // Checksum (8 bit sum of data only) - __u8 Data[0]; // Data starts here + __u8 Data[]; // Data starts here } __attribute__((packed)); // for 5152 devices only (type 2 record) @@ -601,7 +601,7 @@ struct ti_i2c_desc { struct ti_i2c_firmware_rec { __u8 Ver_Major; // Firmware Major version number __u8 Ver_Minor; // Firmware Minor version number - __u8 Data[0]; // Download starts here + __u8 Data[]; // Download starts here } __attribute__((packed)); diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c index ef23acc9b9ce..73075b9351c5 100644 --- a/drivers/usb/serial/ti_usb_3410_5052.c +++ b/drivers/usb/serial/ti_usb_3410_5052.c @@ -219,7 +219,7 @@ struct ti_write_data_bytes { u8 bDataCounter; __be16 wBaseAddrHi; __be16 wBaseAddrLo; - u8 bData[0]; + u8 bData[]; } __packed; struct ti_read_data_request { @@ -234,7 +234,7 @@ struct ti_read_data_bytes { __u8 bCmdCode; __u8 bModuleId; __u8 bErrorCode; - __u8 bData[0]; + __u8 bData[]; } __packed; /* Interrupt struct */ |