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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-28 07:33:37 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-28 12:08:37 -0800 |
| commit | 8402a31dd803e091fd2ec9cd22040b34a0b07085 (patch) | |
| tree | 05be3234ff3267189e4b73c36906e234352655a3 | |
| parent | af71b090c88c12816d43514190790de919921cea (diff) | |
| download | linux-8402a31dd803e091fd2ec9cd22040b34a0b07085.tar.gz linux-8402a31dd803e091fd2ec9cd22040b34a0b07085.tar.bz2 linux-8402a31dd803e091fd2ec9cd22040b34a0b07085.zip | |
net: dccp: 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>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/dccp.h | 2 | ||||
| -rw-r--r-- | net/dccp/ccid.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/dccp.h b/include/linux/dccp.h index 6b64b6cc2175..07e547c02fd8 100644 --- a/include/linux/dccp.h +++ b/include/linux/dccp.h @@ -198,7 +198,7 @@ enum dccp_role { struct dccp_service_list { __u32 dccpsl_nr; - __be32 dccpsl_list[0]; + __be32 dccpsl_list[]; }; #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1) diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h index 70f88f2b4456..105f3734dadb 100644 --- a/net/dccp/ccid.h +++ b/net/dccp/ccid.h @@ -95,7 +95,7 @@ void ccid_cleanup_builtins(void); struct ccid { struct ccid_operations *ccid_ops; - char ccid_priv[0]; + char ccid_priv[]; }; static inline void *ccid_priv(const struct ccid *ccid) |