On Mon, Oct 22, 2018 at 04:43:57PM -0700, ndesaulniers@xxxxxxxxxx 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@xxxxxxxxxx> > Suggested-by: Denis Kenzior <denkenz@xxxxxxxxx> > Suggested-by: James Bottomley <jejb@xxxxxxxxxxxxxxxxxx> > Suggested-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > --- > 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
