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R. Silva" To: Alexander Viro , Christian Brauner Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] readdir: Replace one-element arrays with flexible-array members Message-ID: MIME-Version: 1.0 Content-Disposition: inline X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1769243740120963388?= X-GMAIL-MSGID: =?utf-8?q?1769243740120963388?= 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 Reviewed-by: Kees Cook --- fs/readdir.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/readdir.c b/fs/readdir.c index 9c53edb60c03..b264ce60114d 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -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 {