| 05:39.58 | *** join/#stepcode infobot (~infobot@rikers.org) |
| 05:39.58 | *** topic/#stepcode is STEPcode - data exchange with the technologies of ISO10303 || http://stepcode.org || LOG http://ibot.rikers.org/%23stepcode/ |
| 06:04.57 | *** join/#stepcode kesha__ (~kesha@49.202.239.193) |
| 07:52.34 | *** join/#stepcode kimz (~AndChat56@106.197.168.83) |
| 07:53.58 | *** join/#stepcode kesha_ (~kesha@49.249.1.163) |
| 10:09.50 | *** join/#stepcode kesha__ (~kesha@49.248.244.93) |
| 11:01.21 | *** join/#stepcode kesha_ (~kesha@49.248.244.93) |
| 12:55.01 | *** join/#stepcode mpictor_ (~mpictor_@2600:1015:b115:bfa0:0:9:faf4:5901) |
| 15:22.18 | *** join/#stepcode mpictor_ (~mpictor_@2600:1015:b115:bfa0:0:9:faf4:5901) |
| 17:41.28 | *** join/#stepcode kesha_ (~kesha@49.248.244.93) |
| 18:57.11 | kesha_ | mpictor_: Did you look at this http://paste.kde.org/p5bf0a67b/raw/ ? |
| 19:02.30 | mpictor_ | Hi kesha_ |
| 19:02.43 | mpictor_ | I looked just now |
| 19:03.12 | mpictor_ | sscanf does not know how much space is allocated for the string |
| 19:03.56 | mpictor_ | That is why it is necessary to limit how much it will read |
| 19:05.57 | mpictor_ | http://en.wikipedia.org/wiki/Buffer_overflow |
| 19:08.06 | mpictor_ | Also http://crasseux.com/books/ctutorial/String-overflows-with-scanf.html |
| 19:09.27 | mpictor_ | When you pass a buffer as an argument to sscanf (or any other function), the function only sees a pointer. It has no way to determine how much space is reserved for the string. |
| 19:09.56 | mpictor_ | If the function writes too much, it will overwrite other variables or even code |
| 19:10.56 | mpictor_ | That is one common way a malicious person can break a program |
| 19:36.24 | *** join/#stepcode mpictor (~mpictor_@c-67-177-102-131.hsd1.in.comcast.net) |
| 19:40.57 | *** join/#stepcode mpictor (~mark@2601:d:b280:9:d63d:7eff:fe2d:2505) |
| 20:07.19 | mpictor | starseeker: re pull request 243 - I was under the impression that 203wseds wasn't compatible with any files found in the wild |
| 20:08.26 | mpictor | kesha_: if you replied, I missed it. does what I said make sense? |
| 20:10.46 | kesha_ | mpictor: yes, still I am not very sure about how to avoid that overflow |
| 20:12.36 | mpictor | that's why we need to change %s to %ns (where n is an integer) |
| 20:12.53 | mpictor | which is why I suggested creating a format string with sprintf |
| 20:18.36 | mpictor | #define BUFSIZ 99 //in real code, BUFSIZ would be set in a system header |
| 20:18.37 | mpictor | const unsigned int size = BUFSIZ; |
| 20:18.47 | mpictor | char fmtString[10] = {0}; |
| 20:18.49 | mpictor | snprintf( fmtString, 9, "%%ds", size ); |
| 20:19.00 | mpictor | fmtString now contains "%99s" |
| 20:19.48 | mpictor | oops, the snprintf line should contain 3 %'s |
| 20:20.50 | mpictor | the first pair of % signs prints a '%', then %d prints an int, followed by 's' |