From: Nathan Chancellor <natechancellor@gmail.com>
To: ndesaulniers@google.com
Cc: dhowells@redhat.com, jejb@linux.vnet.ibm.com,
David.Laight@aculab.com, denkenz@gmail.com,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH v2] [PATCH] KEYS: trusted: fix -Wvarags warning
Date: Mon, 22 Oct 2018 17:00:51 -0700 [thread overview]
Message-ID: <20181023000051.GA17367@flashbox> (raw)
In-Reply-To: <20181022234357.82217-1-ndesaulniers@google.com>
On Mon, Oct 22, 2018 at 04:43:57PM -0700, ndesaulniers@google.com wrote:
> Fixes the warning reported by Clang:
> security/keys/trusted.c:146:17: warning: passing an object that
> undergoes default
> argument promotion to 'va_start' has undefined behavior [-Wvarargs]
> va_start(argp, h3);
> ^
> security/keys/trusted.c:126:37: note: parameter of type 'unsigned
> char' is declared here
> unsigned char *h2, unsigned char h3, ...)
> ^
> Specifically, it seems that both the C90 (4.8.1.1) and C11 (7.16.1.4)
> standards explicitly call this out as undefined behavior:
>
> The parameter parmN is the identifier of the rightmost parameter in
> the variable parameter list in the function definition (the one just
> before the ...). If the parameter parmN is declared with ... or with a
> type that is not compatible with the type that results after
> application of the default argument promotions, the behavior is
> undefined.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/41
> Link: https://www.eskimo.com/~scs/cclass/int/sx11c.html
> Suggested-by: David Laight <David.Laight@aculab.com>
> Suggested-by: Denis Kenzior <denkenz@gmail.com>
> Suggested-by: James Bottomley <jejb@linux.vnet.ibm.com>
> Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> v1 -> v2:
> * Don't reorder args, just use default function promotion type
> of unsigned int.
> * Add !! boolean cast as per Denis in
> https://lkml.org/lkml/2018/10/12/838.
> * Tested with gcc-8 and clang-8.
>
> include/keys/trusted.h | 2 +-
> security/keys/trusted.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/keys/trusted.h b/include/keys/trusted.h
> index adbcb6817826..0071298b9b28 100644
> --- a/include/keys/trusted.h
> +++ b/include/keys/trusted.h
> @@ -38,7 +38,7 @@ enum {
>
> int TSS_authhmac(unsigned char *digest, const unsigned char *key,
> unsigned int keylen, unsigned char *h1,
> - unsigned char *h2, unsigned char h3, ...);
> + unsigned char *h2, unsigned int h3, ...);
> int TSS_checkhmac1(unsigned char *buffer,
> const uint32_t command,
> const unsigned char *ononce,
> diff --git a/security/keys/trusted.c b/security/keys/trusted.c
> index ff6789365a12..335ce6d1cf6b 100644
> --- a/security/keys/trusted.c
> +++ b/security/keys/trusted.c
> @@ -123,7 +123,7 @@ static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
> */
> int TSS_authhmac(unsigned char *digest, const unsigned char *key,
> unsigned int keylen, unsigned char *h1,
> - unsigned char *h2, unsigned char h3, ...)
> + unsigned char *h2, unsigned int h3, ...)
> {
> unsigned char paramdigest[SHA1_DIGEST_SIZE];
> struct sdesc *sdesc;
> @@ -139,7 +139,7 @@ int TSS_authhmac(unsigned char *digest, const unsigned char *key,
> return PTR_ERR(sdesc);
> }
>
> - c = h3;
> + c = !!h3;
> ret = crypto_shash_init(&sdesc->shash);
> if (ret < 0)
> goto out;
> --
> 2.19.1.568.g152ad8e336-goog
>
Thank you for the fix!
Nathan
next prev parent reply other threads:[~2018-10-23 0:01 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-09 22:11 undefined behavior (-Wvarargs) in security/keys/trusted.c#TSS_authhmac() Nick Desaulniers
2018-10-11 16:02 ` Arnd Bergmann
2018-10-11 16:10 ` James Bottomley
2018-10-11 20:31 ` [PATCH] KEYS: trusted: fix -Wvarags warning ndesaulniers
2018-10-12 1:50 ` Nathan Chancellor
2018-10-12 16:55 ` Nick Desaulniers
2018-10-12 17:03 ` Nathan Chancellor
2018-10-12 12:29 ` Denis Kenzior
2018-10-12 15:05 ` James Bottomley
2018-10-12 15:13 ` Denis Kenzior
2018-10-12 15:22 ` James Bottomley
2018-10-12 15:44 ` Denis Kenzior
2018-10-12 15:46 ` James Bottomley
2018-10-12 15:53 ` Denis Kenzior
2018-10-12 16:01 ` James Bottomley
2018-10-12 17:14 ` Nick Desaulniers
2018-10-12 15:25 ` James Bottomley
2018-10-12 17:05 ` Nick Desaulniers
2018-10-12 17:17 ` Nick Desaulniers
2018-10-12 17:27 ` Denis Kenzior
2018-10-12 18:39 ` Nick Desaulniers
2018-10-12 17:02 ` Nick Desaulniers
2018-10-12 17:15 ` Denis Kenzior
2018-10-15 9:26 ` David Laight
2018-10-15 21:53 ` Nick Desaulniers
2018-10-16 8:13 ` David Laight
2018-10-22 23:43 ` [PATCH v2] " ndesaulniers
2018-10-23 0:00 ` Nathan Chancellor [this message]
2018-10-24 8:36 ` Jarkko Sakkinen
2018-10-29 17:54 ` Nick Desaulniers
2019-02-11 18:36 ` Nick Desaulniers
2019-02-12 23:12 ` Jarkko Sakkinen
2019-02-14 10:52 ` Jarkko Sakkinen
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