Re: [PATCH] openssl: avoid NULL pointer dereference in three places

[Saul Wold <sgw@linux.intel.com>]

On 08/19/2013 06:59 PM, Xufeng Zhang wrote:
> Hi All,
>
> Anybody help me review this?
>
>
> Thanks,
> Xufeng
>
> On 06/04/2013 02:15 PM, Xufeng Zhang wrote:
>> There are three potential NULL pointer dereference in
>> EVP_DigestInit_ex(), dh_pub_encode() and dsa_pub_encode()
>> functions.
>> Fix them by adding proper null pointer check.
>>
>> [YOCTO #4600]
>> [ CQID: WIND00373257 ]
>>
>> Signed-off-by: Xufeng Zhang<xufeng.zhang@windriver.com>
>> ---
>>   ...-pointer-dereference-in-EVP_DigestInit_ex.patch |   16 +++++++++
>>   ...NULL-pointer-dereference-in-dh_pub_encode.patch |   34
>> ++++++++++++++++++++
>>   meta/recipes-connectivity/openssl/openssl.inc      |    2 +-
>>   .../recipes-connectivity/openssl/openssl_1.0.1e.bb |    2 +
>>   4 files changed, 53 insertions(+), 1 deletions(-)
>>   create mode 100644
>> meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-EVP_DigestInit_ex.patch
>>
>>   create mode 100644
>> meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-dh_pub_encode.patch
>>
>>
>> diff --git
>> a/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-EVP_DigestInit_ex.patch
>> b/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-EVP_DigestInit_ex.patch
>>
>> new file mode 100644
>> index 0000000..69924a4
>> --- /dev/null
>> +++
>> b/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-EVP_DigestInit_ex.patch
>>
>> @@ -0,0 +1,16 @@
>> +openssl: avoid NULL pointer dereference in EVP_DigestInit_ex()
>> +
>> +We should avoid accessing the type pointer if it's NULL,
>> +this could happen if ctx->digest is not NULL.

These patches both need Upstream-Status: and Signed-off-by: Tags

>> +---
>> +--- a/crypto/evp/digest.c
>> ++++ b/crypto/evp/digest.c
>> +@@ -199,7 +199,7 @@
>> +         return 0;
>> +         }
>> + #endif
>> +-    if (ctx->digest != type)
>> ++    if (type&&  (ctx->digest != type))
>> +         {
>> +         if (ctx->digest&&  ctx->digest->ctx_size)
>> +             OPENSSL_free(ctx->md_data);

I am more concerned about this patch as I do not know the code well, but 
if ctx->digest is non-NULL and type is, this code would not be executed 
which would be wrong, correct?  Your changing the behavior of the code 
here. Also reading the code, it should be be possible for type to be 
NULL, unless some memory corruption occurs earlier as there is a check 
at line 153 for !type, which should cause it to goto skip_to_init.

Please verify this patch is really needed.


>> diff --git
>> a/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-dh_pub_encode.patch
>> b/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-dh_pub_encode.patch
>>
>> new file mode 100644
>> index 0000000..642b0ea
>> --- /dev/null
>> +++
>> b/meta/recipes-connectivity/openssl/openssl-1.0.1e/openssl-avoid-NULL-pointer-dereference-in-dh_pub_encode.patch
>>
>> @@ -0,0 +1,34 @@
>> +openssl: avoid NULL pointer dereference in
>> dh_pub_encode()/dsa_pub_encode()
>> +
>> +We should avoid accessing the pointer if ASN1_STRING_new()
>> +allocates memory failed.
>> +---
>> +--- a/crypto/dh/dh_ameth.c
>> ++++ b/crypto/dh/dh_ameth.c
>> +@@ -139,6 +139,12 @@
>> +     dh=pkey->pkey.dh;
>> +
>> +     str = ASN1_STRING_new();
>> ++    if (!str)
>> ++        {
>> ++        DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
>> ++        goto err;
>> ++        }
>> ++
>> +     str->length = i2d_DHparams(dh,&str->data);
>> +     if (str->length<= 0)
>> +         {
>> +--- a/crypto/dsa/dsa_ameth.c
>> ++++ b/crypto/dsa/dsa_ameth.c
>> +@@ -148,6 +148,11 @@
>> +         {
>> +         ASN1_STRING *str;
>> +         str = ASN1_STRING_new();
>> ++        if (!str)
>> ++            {
>> ++            DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
>> ++            goto err;
>> ++            }
>> +         str->length = i2d_DSAparams(dsa,&str->data);
>> +         if (str->length<= 0)
>> +             {
>> diff --git a/meta/recipes-connectivity/openssl/openssl.inc
>> b/meta/recipes-connectivity/openssl/openssl.inc
>> index f5b2432..c753a27 100644
>> --- a/meta/recipes-connectivity/openssl/openssl.inc
>> +++ b/meta/recipes-connectivity/openssl/openssl.inc
>> @@ -5,7 +5,7 @@ BUGTRACKER =
>> "http://www.openssl.org/news/vulnerabilities.html"
>>   SECTION = "libs/network"
>>
>>   # Big Jump for OpenSSL 1.0 support with meta-oe
>> -INC_PR = "r15"
>> +INC_PR = "r16"
>>
No PR or INC_PR Bump needed

>>   # "openssl | SSLeay" dual license
>>   LICENSE = "openssl"
>> diff --git a/meta/recipes-connectivity/openssl/openssl_1.0.1e.bb
>> b/meta/recipes-connectivity/openssl/openssl_1.0.1e.bb
>> index 61de3a6..afd5576 100644
>> --- a/meta/recipes-connectivity/openssl/openssl_1.0.1e.bb
>> +++ b/meta/recipes-connectivity/openssl/openssl_1.0.1e.bb
>> @@ -31,6 +31,8 @@ SRC_URI += "file://configure-targets.patch \
>>               file://openssl_fix_for_x32.patch \
>>               file://openssl-fix-doc.patch \
>>               file://find.pl \
>> +
>> file://openssl-avoid-NULL-pointer-dereference-in-dh_pub_encode.patch \
>> +
>> file://openssl-avoid-NULL-pointer-dereference-in-EVP_DigestInit_ex.patch
>> \
>>              "
>>
>>   SRC_URI[md5sum] = "66bf6f10f060d561929de96f9dfe5b8c"
>
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