diff options
| author | Kees Cook <keescook@chromium.org> | 2021-05-17 20:16:57 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2021-10-18 12:28:52 -0700 |
| commit | 4797632f4f1d8af4e0670adcb97bf9800dc3beca (patch) | |
| tree | d0c145b4b5ac8461f45a2dcf346945faaec8d080 /lib/memcpy_kunit.c | |
| parent | bb95ebbe89a7854368be061acefb22040fbcc486 (diff) | |
string.h: Introduce memset_after() for wiping trailing members/padding
A common idiom in kernel code is to wipe the contents of a structure
after a given member. This is especially useful in places where there is
trailing padding. These open-coded cases are usually difficult to read
and very sensitive to struct layout changes. Introduce a new helper,
memset_after() that takes the target struct instance, the byte to write,
and the member name after which the zeroing should start.
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Francis Laniel <laniel_francis@privacyrequired.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'lib/memcpy_kunit.c')
| -rw-r--r-- | lib/memcpy_kunit.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c index 8b2109bb62df..5c5b4f3221d9 100644 --- a/lib/memcpy_kunit.c +++ b/lib/memcpy_kunit.c @@ -215,6 +215,13 @@ static void memset_test(struct kunit *test) 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, }, }; + struct some_bytes after = { + .data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x72, + 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, + 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, + 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, + }, + }; struct some_bytes dest = { }; int count, value; u8 *ptr; @@ -245,6 +252,12 @@ static void memset_test(struct kunit *test) ptr += 8; memset(ptr++, value++, count++); compare("argument side-effects", dest, three); + + /* Verify memset_after() */ + dest = control; + memset_after(&dest, 0x72, three); + compare("memset_after()", dest, after); + #undef TEST_OP } |