From 6bc3f3979edce0b11deb685a4c817abb7d74b227 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 20 Feb 2020 07:20:17 -0600 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor Signed-off-by: Greg Kroah-Hartman --- drivers/usb/atm/usbatm.h | 2 +- drivers/usb/dwc2/hcd.h | 2 +- drivers/usb/host/ehci-tegra.c | 2 +- drivers/usb/host/ehci.h | 4 ++-- drivers/usb/host/fotg210.h | 2 +- drivers/usb/host/ohci.h | 4 ++-- drivers/usb/host/xhci-mtk.h | 2 +- drivers/usb/host/xhci.h | 4 ++-- drivers/usb/serial/io_usbvend.h | 4 ++-- drivers/usb/serial/ti_usb_3410_5052.c | 4 ++-- include/linux/usb.h | 4 ++-- include/linux/usb/audio-v2.h | 2 +- include/linux/usb/audio-v3.h | 2 +- include/linux/usb/gadget.h | 2 +- include/linux/usb/hcd.h | 2 +- include/linux/usbdevice_fs.h | 2 +- 16 files changed, 22 insertions(+), 22 deletions(-) diff --git a/drivers/usb/atm/usbatm.h b/drivers/usb/atm/usbatm.h index d3bdc4c..8725755 100644 --- a/drivers/usb/atm/usbatm.h +++ b/drivers/usb/atm/usbatm.h @@ -164,7 +164,7 @@ struct usbatm_data { unsigned char *cell_buf; /* holds partial rx cell */ unsigned int buf_usage; - struct urb *urbs[0]; + struct urb *urbs[]; }; static inline void *to_usbatm_driver_data(struct usb_interface *intf) diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h index 8ca6d12..1224fa9 100644 --- a/drivers/usb/dwc2/hcd.h +++ b/drivers/usb/dwc2/hcd.h @@ -199,7 +199,7 @@ struct dwc2_hcd_urb { u32 flags; u16 interval; struct dwc2_hcd_pipe_info pipe_info; - struct dwc2_hcd_iso_packet_desc iso_descs[0]; + struct dwc2_hcd_iso_packet_desc iso_descs[]; }; /* Phases for control transfers */ diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index d6433f2..10d51da 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -282,7 +282,7 @@ done: struct dma_aligned_buffer { void *kmalloc_ptr; void *old_xfer_buffer; - u8 data[0]; + u8 data[]; }; static void free_dma_aligned_buffer(struct urb *urb) diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index ac5e967..229b3de 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -255,7 +255,7 @@ struct ehci_hcd { /* one per controller */ struct list_head tt_list; /* platform-specific data -- must come last */ - unsigned long priv[0] __aligned(sizeof(s64)); + unsigned long priv[] __aligned(sizeof(s64)); }; /* convert between an HCD pointer and the corresponding EHCI_HCD */ @@ -460,7 +460,7 @@ struct ehci_iso_sched { struct list_head td_list; unsigned span; unsigned first_packet; - struct ehci_iso_packet packet[0]; + struct ehci_iso_packet packet[]; }; /* diff --git a/drivers/usb/host/fotg210.h b/drivers/usb/host/fotg210.h index 1b4db95..6cee40e 100644 --- a/drivers/usb/host/fotg210.h +++ b/drivers/usb/host/fotg210.h @@ -490,7 +490,7 @@ struct fotg210_iso_packet { struct fotg210_iso_sched { struct list_head td_list; unsigned span; - struct fotg210_iso_packet packet[0]; + struct fotg210_iso_packet packet[]; }; /* diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h index b015b00..27c26ca 100644 --- a/drivers/usb/host/ohci.h +++ b/drivers/usb/host/ohci.h @@ -337,7 +337,7 @@ typedef struct urb_priv { u16 length; // # tds in this request u16 td_cnt; // tds already serviced struct list_head pending; - struct td *td [0]; // all TDs in this request + struct td *td[]; // all TDs in this request } urb_priv_t; @@ -435,7 +435,7 @@ struct ohci_hcd { struct dentry *debug_dir; /* platform-specific data -- must come last */ - unsigned long priv[0] __aligned(sizeof(s64)); + unsigned long priv[] __aligned(sizeof(s64)); }; diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h index 5ac458b..acd5651 100644 --- a/drivers/usb/host/xhci-mtk.h +++ b/drivers/usb/host/xhci-mtk.h @@ -95,7 +95,7 @@ struct mu3h_sch_ep_info { u32 pkts; u32 cs_count; u32 burst_mode; - u32 bw_budget_table[0]; + u32 bw_budget_table[]; }; #define MU3C_U3_PORT_MAX 4 diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 13d8838..5f47b18 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1642,7 +1642,7 @@ struct xhci_scratchpad { struct urb_priv { int num_tds; int num_tds_done; - struct xhci_td td[0]; + struct xhci_td td[]; }; /* @@ -1893,7 +1893,7 @@ struct xhci_hcd { void *dbc; /* platform-specific data -- must come last */ - unsigned long priv[0] __aligned(sizeof(s64)); + unsigned long priv[] __aligned(sizeof(s64)); }; /* Platform specific overrides to generic XHCI hc_driver ops */ diff --git a/drivers/usb/serial/io_usbvend.h b/drivers/usb/serial/io_usbvend.h index c38e87a..0d1a5bb 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 ef23acc..73075b9 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 */ diff --git a/include/linux/usb.h b/include/linux/usb.h index ca1a5f1..9f3c721 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -325,7 +325,7 @@ struct usb_interface_cache { /* variable-length array of alternate settings for this interface, * stored in no particular order */ - struct usb_host_interface altsetting[0]; + struct usb_host_interface altsetting[]; }; #define ref_to_usb_interface_cache(r) \ container_of(r, struct usb_interface_cache, ref) @@ -1589,7 +1589,7 @@ struct urb { int error_count; /* (return) number of ISO errors */ void *context; /* (in) context for completion */ usb_complete_t complete; /* (in) completion routine */ - struct usb_iso_packet_descriptor iso_frame_desc[0]; + struct usb_iso_packet_descriptor iso_frame_desc[]; /* (in) ISO ONLY */ }; diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h index ba4b3e3..5e31740 100644 --- a/include/linux/usb/audio-v2.h +++ b/include/linux/usb/audio-v2.h @@ -153,7 +153,7 @@ struct uac2_feature_unit_descriptor { __u8 bSourceID; /* bmaControls is actually u32, * but u8 is needed for the hybrid parser */ - __u8 bmaControls[0]; /* variable length */ + __u8 bmaControls[]; /* variable length */ } __attribute__((packed)); /* 4.9.2 Class-Specific AS Interface Descriptor */ diff --git a/include/linux/usb/audio-v3.h b/include/linux/usb/audio-v3.h index 6b70843..c69a6f2 100644 --- a/include/linux/usb/audio-v3.h +++ b/include/linux/usb/audio-v3.h @@ -109,7 +109,7 @@ struct uac3_feature_unit_descriptor { __u8 bSourceID; /* bmaControls is actually u32, * but u8 is needed for the hybrid parser */ - __u8 bmaControls[0]; /* variable length */ + __u8 bmaControls[]; /* variable length */ /* wFeatureDescrStr omitted */ } __attribute__((packed)); diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 124462d..9411c08 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -767,7 +767,7 @@ struct usb_gadget_strings { struct usb_gadget_string_container { struct list_head list; - u8 *stash[0]; + u8 *stash[]; }; /* put descriptor for string with that id into buf (buflen >= 256) */ diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index 712b2a6..e12105e 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -228,7 +228,7 @@ struct usb_hcd { /* The HC driver's private data is stored at the end of * this structure. */ - unsigned long hcd_priv[0] + unsigned long hcd_priv[] __attribute__ ((aligned(sizeof(s64)))); }; diff --git a/include/linux/usbdevice_fs.h b/include/linux/usbdevice_fs.h index 79aab00..14ea197 100644 --- a/include/linux/usbdevice_fs.h +++ b/include/linux/usbdevice_fs.h @@ -69,7 +69,7 @@ struct usbdevfs_urb32 { compat_int_t error_count; compat_uint_t signr; compat_caddr_t usercontext; /* unused */ - struct usbdevfs_iso_packet_desc iso_frame_desc[0]; + struct usbdevfs_iso_packet_desc iso_frame_desc[]; }; struct usbdevfs_ioctl32 { -- 2.7.4