From mboxrd@z Thu Jan 1 00:00:00 1970 From: Akashi Takahiro Date: Thu, 7 May 2020 16:34:16 +0900 Subject: [PATCH 5/8] efi_loader: Make the pkcs7 header parsing function an extern In-Reply-To: <20200430173630.15608-6-sughosh.ganu@linaro.org> References: <20200430173630.15608-1-sughosh.ganu@linaro.org> <20200430173630.15608-6-sughosh.ganu@linaro.org> Message-ID: <20200507073416.GF3330@laputa> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Thu, Apr 30, 2020 at 11:06:27PM +0530, Sughosh Ganu wrote: > The pkcs7 header parsing functionality is pretty generic, and can be > used by other features like capsule authentication. Make the function > as an extern, also changing it's name to efi_parse_pkcs7_header. The patch itself is fine to me, but is "pkcs7 header" a common term? -Takahiro Akashi > > Signed-off-by: Sughosh Ganu > --- > include/efi_loader.h | 2 + > lib/efi_loader/efi_signature.c | 78 ++++++++++++++++++++++++++++++++ > lib/efi_loader/efi_variable.c | 82 +--------------------------------- > 3 files changed, 82 insertions(+), 80 deletions(-) > > diff --git a/include/efi_loader.h b/include/efi_loader.h > index b7638d5825..8d923451ce 100644 > --- a/include/efi_loader.h > +++ b/include/efi_loader.h > @@ -781,6 +781,8 @@ bool efi_secure_boot_enabled(void); > > bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp, > WIN_CERTIFICATE **auth, size_t *auth_len); > +struct pkcs7_message *efi_parse_pkcs7_header(const void *buf, size_t buflen); > + > #endif /* CONFIG_EFI_SECURE_BOOT */ > > #ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > index bf6f39aab2..9897f5418e 100644 > --- a/lib/efi_loader/efi_signature.c > +++ b/lib/efi_loader/efi_signature.c > @@ -25,6 +25,84 @@ const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > > #ifdef CONFIG_EFI_SECURE_BOOT > > +static u8 pkcs7_hdr[] = { > + /* SEQUENCE */ > + 0x30, 0x82, 0x05, 0xc7, > + /* OID: pkcs7-signedData */ > + 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02, > + /* Context Structured? */ > + 0xa0, 0x82, 0x05, 0xb8, > +}; > + > +/** > + * efi_parse_pkcs7_header - parse a signature in variable > + * @buf: Pointer to the payload's value > + * @buflen: Length of @buf > + * > + * Parse a signature embedded in variable's value and instantiate > + * a pkcs7_message structure. Since pkcs7_parse_message() accepts only > + * pkcs7's signedData, some header needed be prepended for correctly > + * parsing authentication data, particularly for variable's. > + * > + * Return: Pointer to pkcs7_message structure on success, NULL on error > + */ > +struct pkcs7_message *efi_parse_pkcs7_header(const void *buf, size_t buflen) > +{ > + u8 *ebuf; > + size_t ebuflen, len; > + struct pkcs7_message *msg; > + > + /* > + * This is the best assumption to check if the binary is > + * already in a form of pkcs7's signedData. > + */ > + if (buflen > sizeof(pkcs7_hdr) && > + !memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) { > + msg = pkcs7_parse_message(buf, buflen); > + goto out; > + } > + > + /* > + * Otherwise, we should add a dummy prefix sequence for pkcs7 > + * message parser to be able to process. > + * NOTE: EDK2 also uses similar hack in WrapPkcs7Data() > + * in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c > + * TODO: > + * The header should be composed in a more refined manner. > + */ > + debug("Makeshift prefix added to authentication data\n"); > + ebuflen = sizeof(pkcs7_hdr) + buflen; > + if (ebuflen <= 0x7f) { > + debug("Data is too short\n"); > + return NULL; > + } > + > + ebuf = malloc(ebuflen); > + if (!ebuf) { > + debug("Out of memory\n"); > + return NULL; > + } > + > + memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr)); > + memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen); > + len = ebuflen - 4; > + ebuf[2] = (len >> 8) & 0xff; > + ebuf[3] = len & 0xff; > + len = ebuflen - 0x13; > + ebuf[0x11] = (len >> 8) & 0xff; > + ebuf[0x12] = len & 0xff; > + > + msg = pkcs7_parse_message(ebuf, ebuflen); > + > + free(ebuf); > + > +out: > + if (IS_ERR(msg)) > + return NULL; > + > + return msg; > +} > + > /** > * efi_hash_regions - calculate a hash value > * @regs: List of regions > diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c > index 6c2dd82306..be34a2cadd 100644 > --- a/lib/efi_loader/efi_variable.c > +++ b/lib/efi_loader/efi_variable.c > @@ -415,85 +415,7 @@ bool efi_secure_boot_enabled(void) > return efi_secure_boot; > } > > -#ifdef CONFIG_EFI_SECURE_BOOT > -static u8 pkcs7_hdr[] = { > - /* SEQUENCE */ > - 0x30, 0x82, 0x05, 0xc7, > - /* OID: pkcs7-signedData */ > - 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02, > - /* Context Structured? */ > - 0xa0, 0x82, 0x05, 0xb8, > -}; > - > -/** > - * efi_variable_parse_signature - parse a signature in variable > - * @buf: Pointer to variable's value > - * @buflen: Length of @buf > - * > - * Parse a signature embedded in variable's value and instantiate > - * a pkcs7_message structure. Since pkcs7_parse_message() accepts only > - * pkcs7's signedData, some header needed be prepended for correctly > - * parsing authentication data, particularly for variable's. > - * > - * Return: Pointer to pkcs7_message structure on success, NULL on error > - */ > -static struct pkcs7_message *efi_variable_parse_signature(const void *buf, > - size_t buflen) > -{ > - u8 *ebuf; > - size_t ebuflen, len; > - struct pkcs7_message *msg; > - > - /* > - * This is the best assumption to check if the binary is > - * already in a form of pkcs7's signedData. > - */ > - if (buflen > sizeof(pkcs7_hdr) && > - !memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) { > - msg = pkcs7_parse_message(buf, buflen); > - goto out; > - } > - > - /* > - * Otherwise, we should add a dummy prefix sequence for pkcs7 > - * message parser to be able to process. > - * NOTE: EDK2 also uses similar hack in WrapPkcs7Data() > - * in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c > - * TODO: > - * The header should be composed in a more refined manner. > - */ > - debug("Makeshift prefix added to authentication data\n"); > - ebuflen = sizeof(pkcs7_hdr) + buflen; > - if (ebuflen <= 0x7f) { > - debug("Data is too short\n"); > - return NULL; > - } > - > - ebuf = malloc(ebuflen); > - if (!ebuf) { > - debug("Out of memory\n"); > - return NULL; > - } > - > - memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr)); > - memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen); > - len = ebuflen - 4; > - ebuf[2] = (len >> 8) & 0xff; > - ebuf[3] = len & 0xff; > - len = ebuflen - 0x13; > - ebuf[0x11] = (len >> 8) & 0xff; > - ebuf[0x12] = len & 0xff; > - > - msg = pkcs7_parse_message(ebuf, ebuflen); > - > - free(ebuf); > - > -out: > - if (IS_ERR(msg)) > - return NULL; > - > - return msg; > -} > +#ifdef CONFIG_SECURE_BOOT > > /** > * efi_variable_authenticate - authenticate a variable > @@ -591,7 +513,7 @@ static efi_status_t efi_variable_authenticate(u16 *variable, > /* variable's signature list */ > if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info)) > goto err; > - var_sig = efi_variable_parse_signature(auth->auth_info.cert_data, > + var_sig = efi_parse_pkcs7_header(auth->auth_info.cert_data, > auth->auth_info.hdr.dwLength > - sizeof(auth->auth_info)); > if (IS_ERR(var_sig)) { > -- > 2.17.1 >