AF_ALG data chunk size

AF_ALG data chunk size

[Yury Stankevich]

Hello,

i'm playing a bit with AF_ALG and found a strange problem: it looks like
big data chunks (64K) can lead to error.


what i do:
1. take a file, read some data (8 or 64K), encrypt, write to
crypted-file, repeat until EOF.
2. read crypted-file, with the same chunk size, decrypt, write to
result-file, repeat until EOF.
3. compare results, and they equal for 8K block size, but differ for 64K
block size. to feed data - i use sendmsg/read calls.


steps to reproduce:
1. clone code from [1]
2. vim crypto.cpp
3. edit read_size to `64 * 1024`
4. make
5. ./test.sh
6. show bug place: xxd crypto X-1; xxd L-decrypt X-2; vimdiff X-1 X-2


system information:
kernel 3.15/x86_64
gcc 4.8.2

[1] - https://github.com/urykhy/avoidSSL

ps: please, CC'me on reply

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