Re: [PATCH v3] sign-file: Fix incorrect return values check

From: Juerg Haefliger <juergh@proton.me>
To: Yusong Gao <a869920004@gmail.com>
Cc: jarkko@kernel.org, davem@davemloft.net, dhowells@redhat.com,
	dwmw2@infradead.org, zohar@linux.ibm.com,
	herbert@gondor.apana.org.au, lists@sapience.com,
	dimitri.ledkov@canonical.com, keyrings@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org
Subject: Re: [PATCH v3] sign-file: Fix incorrect return values check
Date: Wed, 22 Nov 2023 07:20:59 +0000	[thread overview]
Message-ID: <20231122082050.7eeea7bd@smeagol> (raw)
In-Reply-To: <20231121034044.847642-1-a869920004@gmail.com>

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On Tue, 21 Nov 2023 03:40:44 +0000
"Yusong Gao" <a869920004@gmail.com> wrote:

> There are some wrong return values check in sign-file when call OpenSSL
> API. The ERR() check cond is wrong because of the program only check the
> return value is < 0 instead of <= 0. For example:
> 1. CMS_final() return 1 for success or 0 for failure.
> 2. i2d_CMS_bio_stream() returns 1 for success or 0 for failure.
> 3. i2d_TYPEbio() return 1 for success and 0 for failure.
> 4. BIO_free() return 1 for success and 0 for failure.

Good catch! In this case I'd probably be more strict and check for '!= 1'.
See below.

...Juerg

> Link: https://www.openssl.org/docs/manmaster/man3/
> Fixes: e5a2e3c84782 ("scripts/sign-file.c: Add support for signing with a raw signature")
> 
> Signed-off-by: Yusong Gao <a869920004@gmail.com>
> ---
> V1, V2: Clarify the description of git message.
> ---
>  scripts/sign-file.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/scripts/sign-file.c b/scripts/sign-file.c
> index 598ef5465f82..dcebbcd6bebd 100644
> --- a/scripts/sign-file.c
> +++ b/scripts/sign-file.c
> @@ -322,7 +322,7 @@ int main(int argc, char **argv)
>  				     CMS_NOSMIMECAP | use_keyid |
>  				     use_signed_attrs),
>  		    "CMS_add1_signer");
> -		ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
> +		ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) <= 0,

ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,

>  		    "CMS_final");
> 
>  #else
> @@ -341,10 +341,10 @@ int main(int argc, char **argv)
>  			b = BIO_new_file(sig_file_name, "wb");
>  			ERR(!b, "%s", sig_file_name);
>  #ifndef USE_PKCS7
> -			ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0,
> +			ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) <= 0,

ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1,

>  			    "%s", sig_file_name);
>  #else
> -			ERR(i2d_PKCS7_bio(b, pkcs7) < 0,
> +			ERR(i2d_PKCS7_bio(b, pkcs7) <= 0,

ERR(i2d_PKCS7_bio(b, pkcs7) != 1,

>  			    "%s", sig_file_name);
>  #endif
>  			BIO_free(b);
> @@ -374,9 +374,9 @@ int main(int argc, char **argv)
> 
>  	if (!raw_sig) {
>  #ifndef USE_PKCS7
> -		ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
> +		ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) <= 0, "%s", dest_name);

ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);

>  #else
> -		ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name);
> +		ERR(i2d_PKCS7_bio(bd, pkcs7) <= 0, "%s", dest_name);

ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);

>  #endif
>  	} else {
>  		BIO *b;
> @@ -396,7 +396,7 @@ int main(int argc, char **argv)
>  	ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
>  	ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
> 
> -	ERR(BIO_free(bd) < 0, "%s", dest_name);
> +	ERR(BIO_free(bd) <= 0, "%s", dest_name);

ERR(BIO_free(bd) != 1, "%s", dest_name);

> 
>  	/* Finally, if we're signing in place, replace the original. */
>  	if (replace_orig)
> --
> 2.34.1
> 

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