]> git.baikalelectronics.ru Git - kernel.git/commit
dh key: fix rounding up KDF output length
authorEric Biggers <ebiggers@google.com>
Tue, 26 Jun 2018 15:59:46 +0000 (16:59 +0100)
committerJames Morris <james.morris@microsoft.com>
Tue, 26 Jun 2018 16:43:05 +0000 (09:43 -0700)
commitac2df46e709ae192473c7230ca2fb36f6006bf88
treebaf202f770e183d2222468917a1e975d65bb9156
parent74fbcf36fe3c98ca2c2f8129664486ee9db5b724
dh key: fix rounding up KDF output length

Commit f54bce89dc8f ("dh key: get rid of stack allocated array") changed
kdf_ctr() to assume that the length of key material to derive is a
multiple of the digest size.  The length was supposed to be rounded up
accordingly.  However, the round_up() macro was used which only gives
the correct result on power-of-2 arguments, whereas not all hash
algorithms have power-of-2 digest sizes.  In some cases this resulted in
a write past the end of the 'outbuf' buffer.

Fix it by switching to roundup(), which works for non-power-of-2 inputs.

Reported-by: syzbot+486f97f892efeb2075a3@syzkaller.appspotmail.com
Reported-by: syzbot+29d17b7898b41ee120a5@syzkaller.appspotmail.com
Reported-by: syzbot+8a608baf8751184ec727@syzkaller.appspotmail.com
Reported-by: syzbot+d04e58bd384f1fe0b112@syzkaller.appspotmail.com
Fixes: f54bce89dc8f ("dh key: get rid of stack allocated array")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Tycho Andersen <tycho@tycho.ws>
Signed-off-by: James Morris <james.morris@microsoft.com>
security/keys/dh.c