"base64 decode assumes input lines are in multiples of 4 #96" #99
Conversation
Convert base64 implementation of stateless to stateful, so you can feed in successive lines and get back the original binary. The previous stateless implementation assumes that the input has no residual after processing a single line, which is not a semantic guaranteed by the base64-in-email standards (and, in fact, was found while processing exports from Tutanota).
|
@vandys I'm reviewing your code, you don't need to update anything. According to man, bzero has been deprecated in favor of memset, so I reverted that specific change and removed the strings.h include. Seeing that base64 is so common in messages and headers and that hypermail is not processing message parts or headers in parallel, I wonder if it's worth it to allocate and free the state structure each time we get a new part and if it wouldn't be better to just use a variable and fixed memory instead of a pointer and allocated memory. What do you think? |
|
Yes, bcopy/bzero are bad old habits from my old BSD days! |
| free(data); /* this was allocatd by mdecodeQP() */ | ||
| } | ||
| /* |
There was a problem hiding this comment.
as you saw, lines 3435-3440 cause a sigsev in your base64 changes because it frees the memory right after allocating it.
That free there is only meant for the QP decoder. It decodes everything in the single call to the decoder and the data variable is freed afterwards.
No need to change anything
|
@vandys Thank you for your excellent patch. All tests I wrote for it worked well. I edited it a bit (function and state structure names, fields, ...) and manually merged it to the 3.0 branch. 2bd8ed5 I did a small fix. The place where you were freeing the state structure only worked in some cases. I added that release code in the two places where it should have gone. Other than those small changes, I didn't need to change anything. |
Convert base64 implementation of stateless to stateful, so you can feed in successive lines and get back the original binary. The previous stateless implementation assumes that the input has no residual after processing a single line, which is not a semantic guaranteed by the base64-in-email standards (and, in fact, was found while processing exports from Tutanota).