[xmlsec] Extremely odd situation.

[Aleksey Sanin]

Check how openssl, xmlsec and opendcp were compiled:

1) The same compile flags are used (in particular, XMLSEC_NO_SIZE_T).
This is done automatically if pkg-config or other standard tools are
used but might not be working correctly if opendcp is setting compile
flags manually.

2) Make sure that same versions of header/library files are used
across the board during compilation/linking/runtime.

Best,

Aleksey

On 4/25/14, 5:36 PM, Lars Goldschlager wrote:
> Greetings.
> 
> I'm trying to help solve a bug in third party software (opendcp) when
> using libxmlsec to sign and generate files.
> 
> An introduction on the bug can be seen here:
> https://code.google.com/p/opendcp/issues/detail?id=136
> 
> Basically, when using a 64 bit debian system, trying to sign the xml
> file ends up on a segmentation fault in libcrypto with a long stack
> (seen there) of xmlsec calls.
> 
> So far I've come to this spot in the program's code:
> 
> key = xmlSecCryptoAppKeyLoadMemory((unsigned char *)opendcp_private_key,
> strlen((char *)opendcp_private_key), xmlSecKeyDataFormatPem, NULL, NULL,
> NULL);
> 
> key is defined thus:
> xmlSecKeyPtr      key;
> 
> debugging this with gdb, on the 32 bit system, when I enter
> xmlSecOpenSSLAppKeyLoadMemory it looks the same in both 64 and 32 bits.
> 
> Inside the keys, specially key.value.id <http://key.value.id> (for
> example) looks perfectly sane by the moment I reach line 213 of
> src/openssl/app.c:  (as per gdb: print *key.value.id <http://key.value.id>):
> 
> 32bit:
> 
> {klassSize = 88, objSize = 16, name = 0xb7d6a4ba "rsa", usage = 28, href
> = 0xb7d6a480 "http://www.w3.org/2000/09/xmldsig#RSAKeyValue",
>   dataNodeName = 0xb7d6a4ae "RSAKeyValue", dataNodeNs = 0x81a2a40
> "http://www.w3.org/2000/09/xmldsig#", initialize = 0xb7d8f21e
> <xmlSecOpenSSLKeyDataRsaInitialize>,
>   duplicate = 0xb7d8f0fc <xmlSecOpenSSLKeyDataRsaDuplicate>, finalize =
> 0xb7d8f05d <xmlSecOpenSSLKeyDataRsaFinalize>, generate = 0xb7d9009e
> <xmlSecOpenSSLKeyDataRsaGenerate>,
>   getType = 0xb7d90d4b <xmlSecOpenSSLKeyDataRsaGetType>, getSize =
> 0xb7d90a79 <xmlSecOpenSSLKeyDataRsaGetSize>, getIdentifier = 0,
>   xmlRead = 0xb7d8f8f3 <xmlSecOpenSSLKeyDataRsaXmlRead>, xmlWrite =
> 0xb7d90474 <xmlSecOpenSSLKeyDataRsaXmlWrite>, binRead = 0, binWrite = 0,
>   debugDump = 0xb7d90c44 <xmlSecOpenSSLKeyDataRsaDebugDump>,
> debugXmlDump = 0xb7d90b3d <xmlSecOpenSSLKeyDataRsaDebugXmlDump>,
> reserved0 = 0x0, reserved1 = 0x0}
> 
> 64bit:
> 
> {klassSize = 168, objSize = 32, name = 0x7ffff711ee9a "rsa", usage = 28,
> href = 0x7ffff711ee60 "http://www.w3.org/2000/09/xmldsig#RSAKeyValue",
>   dataNodeName = 0x7ffff711ee8e "RSAKeyValue", dataNodeNs = 0x7772c0
> "http://www.w3.org/2000/09/xmldsig#", initialize = 0x7ffff7348f62
> <xmlSecOpenSSLKeyDataRsaInitialize>,
>   duplicate = 0x7ffff7348e4f <xmlSecOpenSSLKeyDataRsaDuplicate>,
> finalize = 0x7ffff7348dcf <xmlSecOpenSSLKeyDataRsaFinalize>,
>   generate = 0x7ffff7349caa <xmlSecOpenSSLKeyDataRsaGenerate>, getType =
> 0x7ffff734a844 <xmlSecOpenSSLKeyDataRsaGetType>,
>   getSize = 0x7ffff734a5bc <xmlSecOpenSSLKeyDataRsaGetSize>,
> getIdentifier = 0, xmlRead = 0x7ffff7349561
> <xmlSecOpenSSLKeyDataRsaXmlRead>,
>   xmlWrite = 0x7ffff734a00c <xmlSecOpenSSLKeyDataRsaXmlWrite>, binRead =
> 0, binWrite = 0, debugDump = 0x7ffff734a750
> <xmlSecOpenSSLKeyDataRsaDebugDump>,
>   debugXmlDump = 0x7ffff734a65c <xmlSecOpenSSLKeyDataRsaDebugXmlDump>,
> reserved0 = 0x0, reserved1 = 0x0}
> 
> But now, after lines
> 
> 214: BIO_free(bio);
> 
> and
> 
> 215: return(key);
> 
> On 32 bit the key pointer returned from the function call contains the
> same, sane info:
> 
> {klassSize = 88, objSize = 16, name = 0xb7d6a4ba "rsa", usage = 28, href
> = 0xb7d6a480 "http://www.w3.org/2000/09/xmldsig#RSAKeyValue",
>   dataNodeName = 0xb7d6a4ae "RSAKeyValue", dataNodeNs = 0x81a2a40
> "http://www.w3.org/2000/09/xmldsig#", initialize = 0xb7d8f21e
> <xmlSecOpenSSLKeyDataRsaInitialize>,
>   duplicate = 0xb7d8f0fc <xmlSecOpenSSLKeyDataRsaDuplicate>, finalize =
> 0xb7d8f05d <xmlSecOpenSSLKeyDataRsaFinalize>, generate = 0xb7d9009e
> <xmlSecOpenSSLKeyDataRsaGenerate>,
>   getType = 0xb7d90d4b <xmlSecOpenSSLKeyDataRsaGetType>, getSize =
> 0xb7d90a79 <xmlSecOpenSSLKeyDataRsaGetSize>, getIdentifier = 0,
>   xmlRead = 0xb7d8f8f3 <xmlSecOpenSSLKeyDataRsaXmlRead>, xmlWrite =
> 0xb7d90474 <xmlSecOpenSSLKeyDataRsaXmlWrite>, binRead = 0, binWrite = 0,
>   debugDump = 0xb7d90c44 <xmlSecOpenSSLKeyDataRsaDebugDump>,
> debugXmlDump = 0xb7d90b3d <xmlSecOpenSSLKeyDataRsaDebugXmlDump>,
> reserved0 = 0x0, reserved1 = 0x0}
> 
> But the pointer in the 64 bit system contains something entirely crazy
> in key.value.id <http://key.value.id>:
> 
> {klassSize = 137438953640, objSize = 140737338535578, name = 0x1c
> <Address 0x1c out of bounds>, usage = 4145147488, href = 0x7ffff711ee8e
> "RSAKeyValue",
>   dataNodeName = 0x7772c0 "http://www.w3.org/2000/09/xmldsig#",
> dataNodeNs = 0x7ffff7348f62
> "USH\203\354\030H\211\375H\205\377t'H\213\037H\205\333t\037\201;\247",
>   initialize = 0x7ffff7348e4f <xmlSecOpenSSLKeyDataRsaDuplicate>,
> duplicate = 0x7ffff7348dcf <xmlSecOpenSSLKeyDataRsaFinalize>,
>   finalize = 0x7ffff7349caa <xmlSecOpenSSLKeyDataRsaGenerate>, generate
> = 0x7ffff734a844 <xmlSecOpenSSLKeyDataRsaGetType>,
>   getType = 0x7ffff734a5bc <xmlSecOpenSSLKeyDataRsaGetSize>, getSize =
> 0, getIdentifier = 0x7ffff7349561 <xmlSecOpenSSLKeyDataRsaXmlRead>,
>   xmlRead = 0x7ffff734a00c <xmlSecOpenSSLKeyDataRsaXmlWrite>, xmlWrite =
> 0, binRead = 0, binWrite = 0x7ffff734a750
> <xmlSecOpenSSLKeyDataRsaDebugDump>,
>   debugDump = 0x7ffff734a65c <xmlSecOpenSSLKeyDataRsaDebugXmlDump>,
> debugXmlDump = 0, reserved0 = 0x0, reserved1 = 0x0}
> 
> At first i suspected the call on line 214: BIO_free(bio); of havign
> troubles because the work space was being freed before the key pointer
> being returned (I do not know nothing of openssl and BIO calls as a
> library, sorry). but this should fail always, not work in one
> architecture and not the other.
> 
> And in opendcp (you can check in the same repository where the ticket I
> linked is. this file:
> https://code.google.com/p/opendcp/source/browse/libopendcp/opendcp_xml_sign.c
> line 385) I check the returned key pointer as soon as it's returned (by
> line 386). So nothing else was run on that pointer by that time in theory.
> 
> I can't grasp how or why this ocurrs. But this unchains a chain of
> events that ends up causing a segfault which I posted there under the
> name Lars. (second or third post)....
> 
> Versions I'm using:
> 
> xmlsec: 1.2.19 (this happens too with debian's default 1.2.18, I
> compiled 1.2.19 to enable debug symbols and have source).
> openssl: 1.0.1e-2+deb7u4 (Basically 1.0.1e patched to close heartbleed).
> gcc: 4.7.2-1
> 
> Everything is adm64 arch. The workign i386 versions of the libraries are
> exactly the same versions as the 64 bit ones (including my own compiled
> xmlsec with the same confiure flags).
> 
> Any feedback is highly welcome.
> 
> Lars.
> 
> 
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