user/sven/linux.git/scripts/gcc-plugins/randomize_layout_plugin.c, branch v6.1.4

gcc-plugins: use KERNELVERSION for plugin version

2022-05-24T15:25:16Z

Commit 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") broke parallel builds. Instead of adding the dependency between GCC plugins and utsrelease.h, let's use KERNELVERSION, which does not require any build artifact. Another reason why I want to avoid utsrelease.h is because it depends on CONFIG_LOCALVERSION(_AUTO) and localversion* files. (include/generated/utsrelease.h depends on include/config/kernel.release, which is generated by scripts/setlocalversion) I want to keep host tools independent of the kernel configuration. There is no good reason to rebuild GCC plugins just because of CONFIG_LOCALVERSION being changed. We just want to associate the plugin versions with the kernel source version. KERNELVERSION should be enough for our purpose. Fixes: 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") Reported-by: kernel test robot Link: https://lore.kernel.org/linux-mm/202205230239.EZxeZ3Fv-lkp@intel.com Reported-by: Guenter Roeck Signed-off-by: Masahiro Yamada Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220524135541.1453693-1-masahiroy@kernel.org

gcc-plugins: randstruct: Remove cast exception handling

2022-05-16T23:02:21Z

With all randstruct exceptions removed, remove all the exception handling code. Any future warnings are likely to be shared between this plugin and Clang randstruct, and will need to be addressed in a more wholistic fashion. Cc: Christoph Hellwig Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook

af_unix: Silence randstruct GCC plugin warning

2022-05-16T23:02:21Z

While preparing for Clang randstruct support (which duplicated many of the warnings the randstruct GCC plugin warned about), one strange one remained only for the randstruct GCC plugin. Eliminating this rids the plugin of the last exception. It seems the plugin is happy to dereference individual members of a cross-struct cast, but it is upset about casting to a whole object pointer. This only manifests in one place in the kernel, so just replace the variable with individual member accesses. There is no change in executable instruction output. Drop the last exception from the randstruct GCC plugin. Cc: "David S. Miller" Cc: Christoph Hellwig Cc: Paolo Abeni Cc: Alexei Starovoitov Cc: Cong Wang Cc: Al Viro Cc: netdev@vger.kernel.org Cc: linux-hardening@vger.kernel.org Acked-by: Kuniyuki Iwashima Link: https://lore.kernel.org/lkml/20220511022217.58586-1-kuniyu@amazon.co.jp Acked-by: Jakub Kicinski Link: https://lore.kernel.org/lkml/20220511151542.4cb3ff17@kernel.org Signed-off-by: Kees Cook

niu: Silence randstruct warnings

2022-05-16T23:02:21Z

Clang randstruct gets upset when it sees struct addresspace (which is randomized) being assigned to a struct page (which is not randomized): drivers/net/ethernet/sun/niu.c:3385:12: error: casting from randomized structure pointer type 'struct address_space *' to 'struct page *' *link = (struct page *) page->mapping; ^ It looks like niu.c is looking for an in-line place to chain its allocated pages together and is overloading the "mapping" member, as it is unused. This is very non-standard, and is expected to be cleaned up in the future[1], but there is no "correct" way to handle it today. No meaningful machine code changes result after this change, and source readability is improved. Drop the randstruct exception now that there is no "confusing" cross-type assignment. [1] https://lore.kernel.org/lkml/YnqgjVoMDu5v9PNG@casper.infradead.org/ Cc: "Matthew Wilcox (Oracle)" Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Du Cheng Cc: Christophe JAILLET Cc: Vlastimil Babka Cc: William Kucharski Cc: Arnd Bergmann Cc: Nathan Chancellor Cc: netdev@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-hardening@vger.kernel.org Acked-by: Jakub Kicinski Link: https://lore.kernel.org/lkml/20220511151647.7290adbe@kernel.org Signed-off-by: Kees Cook

big_keys: Use struct for internal payload

2022-05-16T23:02:21Z

The randstruct GCC plugin gets upset when it sees struct path (which is randomized) being assigned from a "void *" (which it cannot type-check). There's no need for these casts, as the entire internal payload use is following a normal struct layout. Convert the enum-based void * offset dereferencing to the new big_key_payload struct. No meaningful machine code changes result after this change, and source readability is improved. Drop the randstruct exception now that there is no "confusing" cross-type assignment. Cc: David Howells Cc: Eric Biggers Cc: Christoph Hellwig Cc: Jarkko Sakkinen Cc: James Morris Cc: "Serge E. Hallyn" Cc: linux-hardening@vger.kernel.org Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Kees Cook

gcc-plugins: Change all version strings match kernel

2022-05-10T23:54:33Z

It's not meaningful for the GCC plugins to track their versions separately from the rest of the kernel. Switch all versions to the kernel version. Fix mismatched indenting while we're at it. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook

security: don't treat structure as an array of struct hlist_head

2022-04-13T19:15:53Z

The initialization of "security_hook_heads" is done by casting it to another structure pointer type, and treating it as an array of "struct hlist_head" objects. This requires an exception be made in "randstruct", because otherwise it will emit an error, reducing the effectiveness of the hardening technique. Instead of using a cast, initialize the individual struct hlist_head elements in security_hook_heads explicitly. This removes the need for the cast and randstruct exception. Signed-off-by: Bill Wendling Cc: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220407175930.471870-1-morbo@google.com

gcc-plugins: remove code for GCC versions older than 4.9

2020-12-04T22:09:41Z

Documentation/process/changes.rst says the minimal GCC version is 4.9. Hence, BUILDING_GCC_VERSION is greater than or equal to 4009. Signed-off-by: Masahiro Yamada Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20201202134929.99883-1-masahiroy@kernel.org

randstruct: Check member structs in is_pure_ops_struct()

2019-07-31T20:13:22Z

While no uses in the kernel triggered this case, it was possible to have a false negative where a struct contains other structs which contain only function pointers because of unreachable code in is_pure_ops_struct(). Signed-off-by: Joonwon Kang Link: https://lore.kernel.org/r/20190727155841.GA13586@host Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook

security: convert security hooks to use hlist

2018-03-31T02:18:27Z

This changes security_hook_heads to use hlist_heads instead of the circular doubly-linked list heads. This should cut down the size of the struct by about half. In addition, it allows mutation of the hooks at the tail of the callback list without having to modify the head. The longer-term purpose of this is to enable making the heads read only. Signed-off-by: Sargun Dhillon Reviewed-by: Tetsuo Handa Acked-by: Casey Schaufler Signed-off-by: James Morris