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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-24 10:21:00 -0600 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2020-03-06 12:28:21 +1100 |
| commit | 5a8a076506af03f83f83d80412a7c0b06b687ee1 (patch) | |
| tree | 3748195e05adfc39d2516d7d077d782067a290a1 /include/crypto/if_alg.h | |
| parent | d282eeeb112a00b05595a034ac4cae8532a4c2fc (diff) | |
| download | linux-5a8a076506af03f83f83d80412a7c0b06b687ee1.tar.bz2 | |
crypto: 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>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto/if_alg.h')
| -rw-r--r-- | include/crypto/if_alg.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index 24cfa96f98ea..56527c85d122 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -66,7 +66,7 @@ struct af_alg_sgl { struct af_alg_tsgl { struct list_head list; unsigned int cur; /* Last processed SG entry */ - struct scatterlist sg[0]; /* Array of SGs forming the SGL */ + struct scatterlist sg[]; /* Array of SGs forming the SGL */ }; #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \ |