Re: How to empty a BIO buffer?
In message CALiegfmvaG-nc=putyxey20otoiow6op+lajohnoqxf86aw...@mail.gmail.com on Mon, 8 Sep 2014 18:19:09 +0200, Iñaki Baz Castillo i...@aliax.net said: ibc Why do I need to provide BIO_get_mem_data() with an already allocated ibc buffer? I've checked the function and I do not understand what it ibc does). The only I want is to get the pointer to the BIO's buffer in ibc which SSL_write() wrote. Why should I provide an allocated buffer? The ibc BIO already has a buffer and the data is already in there after ibc calling SSL_write(). Why do I need to pass an allocated buffer? Actually, you don't, you only need to pass it the address to a char* (that's what a char** is). This code snippet (which is your code snippet that crashes with a small change) is sufficient: -- long read; char* data = NULL; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); -- Cheers, Richard -- Richard Levitte rich...@levitte.org http://richard.levitte.org/ Life is a tremendous celebration - and I'm invited! -- from a friend's blog, translated from Swedish __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
And of course, I noticed this email after sending my own... sorry. In message CALiegf=BytJ-1ZDzcCw3=e2=6moritr87pjunro4cxorysy...@mail.gmail.com on Mon, 8 Sep 2014 18:41:40 +0200, Iñaki Baz Castillo i...@aliax.net said: ibc 2014-09-08 18:35 GMT+02:00 Kyle Hamilton aerow...@gmail.com: ibc The allocated buffer needs to be sizeof(char *). What's happening is the ibc address of the buffer (buffer[0]) gets written to the ibc pointer-to-pointer-to-char, data. If data == NULL, you're asking to write ibc the address of the buffer to unallocated memory. ibc ibc It's done this way because the return value of the function is the number of ibc valid bytes you can read from that location, and the address must go ibc somewhere for you to get the data from it. ibc ibc I'm sorry this is probably difficult to understand, I don't know if I can ibc explain it more easily. ibc ibc It's clear. And my error was terrible, I was creating a char** data ibc instead of char* data. The following updated code does work: ibc ibc ibc - ibc long read; ibc char* data = NULL; ibc ibc read = BIO_get_mem_data(bio, data); ibc ibc // Use data and read values. ibc - ibc ibc ibc Thanks a lot. ibc ibc ibc -- ibc Iñaki Baz Castillo ibc i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
2014-09-09 10:46 GMT+02:00 Richard Levitte rich...@levitte.org: And of course, I noticed this email after sending my own... sorry. :) Thanks a lot. -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
How to empty a BIO buffer?
Hi, I'm trying to avoid a BIO_read() call given that it copies the BIO buffer data into a buffer I must provide to the function. I use a BIO memory pair. In my case it would be nice if I can get the pointer and length of the current BIO buffer and then tell the BIO to empty/clean it. So I want to replace this code: -- int read = BIO_read(sslBioToNetwork, (void*)myBuffer, MY_BUFFER_SIZE); // Use the read data -- with something like this: --- long read; char** data = (char**)myBuffer; read = BIO_get_mem_data(sslBioToNetwork, data); // Emtpy the BIO buffer data, HOW? // Use the read data --- But I do not know how to empty the already read BIO buffer data. BIO_flush() does nothing. How may I do this? Thanks a lot. -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
2014-09-08 14:44 GMT+02:00 Iñaki Baz Castillo i...@aliax.net: -- int read = BIO_read(sslBioToNetwork, (void*)myBuffer, MY_BUFFER_SIZE); // Use the read data -- with something like this: --- long read; char** data = (char**)myBuffer; read = BIO_get_mem_data(sslBioToNetwork, data); // Emtpy the BIO buffer data, HOW? // Use the read data --- But I do not know how to empty the already read BIO buffer data. BIO_flush() does nothing. Sorry, BIO_flush() works. The problem is that calling BIO_eof() after BIO_flush() does not return 1 so I get a loop. Updated my code not to check BIO_eof() after BIO_flush(). -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
In message CALiegf=+4vr1GU=mn4r0hng99orugtvez+xxjogpbkzx-uz...@mail.gmail.com on Mon, 8 Sep 2014 15:10:04 +0200, Iñaki Baz Castillo i...@aliax.net said: ibc 2014-09-08 14:44 GMT+02:00 Iñaki Baz Castillo i...@aliax.net: ibc -- ibc int read = BIO_read(sslBioToNetwork, (void*)myBuffer, MY_BUFFER_SIZE); ibc ibc // Use the read data ibc -- ibc ibc with something like this: ibc ibc --- ibc long read; ibc char** data = (char**)myBuffer; ibc ibc read = BIO_get_mem_data(sslBioToNetwork, data); ibc ibc // Emtpy the BIO buffer data, HOW? ibc ibc // Use the read data ibc --- ibc ibc ibc But I do not know how to empty the already read BIO buffer data. ibc BIO_flush() does nothing. ibc ibc ibc Sorry, BIO_flush() works. The problem is that calling BIO_eof() after ibc BIO_flush() does not return 1 so I get a loop. Updated my code not to ibc check BIO_eof() after BIO_flush(). Sorry, BIO_flush() isn't what you want (it doesn't reset the buffer to empty), BIO_reset() is. However, you need to be careful... if I were you, I would use the read data before resetting, as BIO_get_mem_data() gives you the pointer to the internal BIO_s_mem buffer, not to a duplicate of it. Cheers, Richard -- Richard Levitte rich...@levitte.org http://richard.levitte.org/ Life is a tremendous celebration - and I'm invited! -- from a friend's blog, translated from Swedish __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
2014-09-08 16:08 GMT+02:00 Richard Levitte rich...@levitte.org: Sorry, BIO_flush() isn't what you want (it doesn't reset the buffer to empty), BIO_reset() is. However, you need to be careful... if I were you, I would use the read data before resetting, as BIO_get_mem_data() gives you the pointer to the internal BIO_s_mem buffer, not to a duplicate of it. Thanks, it does work. However... I do not understand how... This works fine: --- long read; // myBuffer is an already allocated buffer. char** data = (char**)myBuffer; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); --- This crashes: --- long read; char** data = NULL; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); --- Why do I need to provide BIO_get_mem_data() with an already allocated buffer? I've checked the function and I do not understand what it does). The only I want is to get the pointer to the BIO's buffer in which SSL_write() wrote. Why should I provide an allocated buffer? The BIO already has a buffer and the data is already in there after calling SSL_write(). Why do I need to pass an allocated buffer? Thanks a lot. -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
2014-09-08 18:19 GMT+02:00 Iñaki Baz Castillo i...@aliax.net: This works fine: --- long read; // myBuffer is an already allocated buffer. char** data = (char**)myBuffer; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); --- BTW I've realized that it also works by removing the BIO_reset() call. I assume that SSL_write() writes into the BIO and overrides the existing data (and the BIO buffer length gets updated with the most recent written data). -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: How to empty a BIO buffer?
The allocated buffer needs to be sizeof(char *). What's happening is the address of the buffer (buffer[0]) gets written to the pointer-to-pointer-to-char, data. If data == NULL, you're asking to write the address of the buffer to unallocated memory. It's done this way because the return value of the function is the number of valid bytes you can read from that location, and the address must go somewhere for you to get the data from it. I'm sorry this is probably difficult to understand, I don't know if I can explain it more easily. -Kyle H On September 8, 2014 9:19:09 AM PST, Iñaki Baz Castillo i...@aliax.net wrote: 2014-09-08 16:08 GMT+02:00 Richard Levitte rich...@levitte.org: Sorry, BIO_flush() isn't what you want (it doesn't reset the buffer to empty), BIO_reset() is. However, you need to be careful... if I were you, I would use the read data before resetting, as BIO_get_mem_data() gives you the pointer to the internal BIO_s_mem buffer, not to a duplicate of it. Thanks, it does work. However... I do not understand how... This works fine: --- long read; // myBuffer is an already allocated buffer. char** data = (char**)myBuffer; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); --- This crashes: --- long read; char** data = NULL; read = BIO_get_mem_data(bio, data); // Use data and read values. BIO_reset(bio); --- Why do I need to provide BIO_get_mem_data() with an already allocated buffer? I've checked the function and I do not understand what it does). The only I want is to get the pointer to the BIO's buffer in which SSL_write() wrote. Why should I provide an allocated buffer? The BIO already has a buffer and the data is already in there after calling SSL_write(). Why do I need to pass an allocated buffer? Thanks a lot. -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
Re: How to empty a BIO buffer?
2014-09-08 18:35 GMT+02:00 Kyle Hamilton aerow...@gmail.com: The allocated buffer needs to be sizeof(char *). What's happening is the address of the buffer (buffer[0]) gets written to the pointer-to-pointer-to-char, data. If data == NULL, you're asking to write the address of the buffer to unallocated memory. It's done this way because the return value of the function is the number of valid bytes you can read from that location, and the address must go somewhere for you to get the data from it. I'm sorry this is probably difficult to understand, I don't know if I can explain it more easily. It's clear. And my error was terrible, I was creating a char** data instead of char* data. The following updated code does work: - long read; char* data = NULL; read = BIO_get_mem_data(bio, data); // Use data and read values. - Thanks a lot. -- Iñaki Baz Castillo i...@aliax.net __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
