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| author |   Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 14:05:49 -0500 |
|---|---|---|
| committer |   Dominik Brodowski <linux@dominikbrodowski.net> | 2020-05-18 10:28:31 +0200 |
| commit | 06ed6aa56ffac9241e03a24649e8d048f8f1b10c (patch) | |
| tree | 31cc68ae56ce5e57befdaca9cd891f6843435d13 /include/pcmcia | |
| parent | Linux 5.7-rc6 (diff) | |
| download | wireguard-linux-06ed6aa56ffac9241e03a24649e8d048f8f1b10c.tar.xz wireguard-linux-06ed6aa56ffac9241e03a24649e8d048f8f1b10c.zip | |
pcmcia: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Diffstat (limited to 'include/pcmcia')
| -rw-r--r-- | include/pcmcia/cistpl.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/pcmcia/cistpl.h b/include/pcmcia/cistpl.h index 59a011101e0e..749320cc9aba 100644 --- a/include/pcmcia/cistpl.h +++ b/include/pcmcia/cistpl.h @@ -161,7 +161,7 @@ typedef struct cistpl_funcid_t { typedef struct cistpl_funce_t { u_char type; - u_char data[0]; + u_char data[]; } cistpl_funce_t; /*====================================================================== @@ -255,7 +255,7 @@ typedef struct cistpl_data_serv_t { u_char escape; u_char encrypt; u_char misc_features; - u_char ccitt_code[0]; + u_char ccitt_code[]; } cistpl_data_serv_t; typedef struct cistpl_fax_serv_t { @@ -265,7 +265,7 @@ typedef struct cistpl_fax_serv_t { u_char encrypt; u_char features_0; u_char features_1; - u_char ccitt_code[0]; + u_char ccitt_code[]; } cistpl_fax_serv_t; typedef struct cistpl_voice_serv_t { |