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readdir: Replace one-element arrays with flexible-array members

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One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element arrays with flexible-array
members in multiple structures.

Address the following -Wstringop-overflow warnings seen when built
m68k architecture with m5307c3_defconfig configuration:
In function '__put_user_fn',
    inlined from 'fillonedir' at fs/readdir.c:170:2:
include/asm-generic/uaccess.h:49:35: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
   49 |                 *(u8 __force *)to = *(u8 *)from;
      |                 ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
fs/readdir.c: In function 'fillonedir':
fs/readdir.c:134:25: note: at offset 1 into destination object 'd_name' of size 1
  134 |         char            d_name[1];
      |                         ^~~~~~
In function '__put_user_fn',
    inlined from 'filldir' at fs/readdir.c:257:2:
include/asm-generic/uaccess.h:49:35: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
   49 |                 *(u8 __force *)to = *(u8 *)from;
      |                 ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
fs/readdir.c: In function 'filldir':
fs/readdir.c:211:25: note: at offset 1 into destination object 'd_name' of size 1
  211 |         char            d_name[1];
      |                         ^~~~~~

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/312
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-Id: <ZJHiPJkNKwxkKz1c@work>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Gustavo A. R. Silva 2023-06-20 11:30:36 -06:00 committed by Christian Brauner
parent d7439fb1f4
commit 2507135e4f
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 4 additions and 4 deletions
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fs/readdir.c
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@ -131,7 +131,7 @@ struct old_linux_dirent {
unsigned long d_ino;
unsigned long d_offset;
unsigned short d_namlen;
char d_name[1];
char d_name[];
};
struct readdir_callback {
@ -208,7 +208,7 @@ struct linux_dirent {
unsigned long d_ino;
unsigned long d_off;
unsigned short d_reclen;
char d_name[1];
char d_name[];
};
struct getdents_callback {
@ -388,7 +388,7 @@ struct compat_old_linux_dirent {
compat_ulong_t d_ino;
compat_ulong_t d_offset;
unsigned short d_namlen;
char d_name[1];
char d_name[];
};
struct compat_readdir_callback {
@ -460,7 +460,7 @@ struct compat_linux_dirent {
compat_ulong_t d_ino;
compat_ulong_t d_off;
unsigned short d_reclen;
char d_name[1];
char d_name[];
};
struct compat_getdents_callback {