Commit 3b9274ea authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Ard Biesheuvel

efi/apple-properties: 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
inadvertenly introduced[3] to the codebase from now on.

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 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200211231421.GA15697@embeddedorSigned-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent b92165d2
...@@ -31,7 +31,7 @@ __setup("dump_apple_properties", dump_properties_enable); ...@@ -31,7 +31,7 @@ __setup("dump_apple_properties", dump_properties_enable);
struct dev_header { struct dev_header {
u32 len; u32 len;
u32 prop_count; u32 prop_count;
struct efi_dev_path path[0]; struct efi_dev_path path[];
/* /*
* followed by key/value pairs, each key and value preceded by u32 len, * followed by key/value pairs, each key and value preceded by u32 len,
* len includes itself, value may be empty (in which case its len is 4) * len includes itself, value may be empty (in which case its len is 4)
...@@ -42,7 +42,7 @@ struct properties_header { ...@@ -42,7 +42,7 @@ struct properties_header {
u32 len; u32 len;
u32 version; u32 version;
u32 dev_count; u32 dev_count;
struct dev_header dev_header[0]; struct dev_header dev_header[];
}; };
static void __init unmarshal_key_value_pairs(struct dev_header *dev_header, static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
......
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