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Macroise the cumbersome read idioms in the BPPs.

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Now the three 'proper' BPPs each have a BPP_READ() macro that wraps up
the fiddly combination of crMaybeWaitUntilV and bufchainery they use
to read a fixed-length amount of input data. The sshverstring 'BPP'
doesn't read fixed-length data in quite the same way, but it has a
similar BPP_WAITFOR macro.

No functional change. Mostly this is just a cleanup to make the code
more legible, but also, the new macros will be a good place to
centralise anything else that needs doing on every read, such as EOF
checking.
This commit is contained in:
Simon Tatham
2018-09-24 14:23:52 +01:00
parent 96622d17a3
commit d77b95cb42
4 changed files with 39 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
ssh2bpp.c
View File

@ -158,6 +158,12 @@ void ssh2_bpp_new_incoming_crypto(
s->pending_newkeys = FALSE;
}
#define BPP_READ(ptr, len) do \
{ \
crMaybeWaitUntilV(bufchain_try_fetch_consume( \
s->bpp.in_raw, ptr, len)); \
} while (0)
static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
{
struct ssh2_bpp_state *s = FROMFIELD(bpp, struct ssh2_bpp_state, bpp);
@ -206,8 +212,7 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
}
/* Read an amount corresponding to the MAC. */
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw, s->buf, s->maclen));
BPP_READ(s->buf, s->maclen);
s->packetlen = 0;
ssh2_mac_start(s->in.mac);
@ -216,10 +221,7 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
for (;;) { /* Once around this loop per cipher block. */
/* Read another cipher-block's worth, and tack it on to
* the end. */
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw,
s->buf + (s->packetlen + s->maclen),
s->cipherblk));
BPP_READ(s->buf + (s->packetlen + s->maclen), s->cipherblk);
/* Decrypt one more block (a little further back in
* the stream). */
ssh2_cipher_decrypt(s->in.cipher,
@ -262,8 +264,7 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
* OpenSSH encrypt-then-MAC mode: the packet length is
* unencrypted, unless the cipher supports length encryption.
*/
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw, s->buf, 4));
BPP_READ(s->buf, 4);
/* Cipher supports length decryption, so do it */
if (s->in.cipher && (ssh2_cipher_alg(s->in.cipher)->flags &
@ -307,9 +308,7 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
/*
* Read the remainder of the packet.
*/
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw, s->data + 4,
s->packetlen + s->maclen - 4));
BPP_READ(s->data + 4, s->packetlen + s->maclen - 4);
/*
* Check the MAC.
@ -334,8 +333,7 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
* Acquire and decrypt the first block of the packet. This will
* contain the length and padding details.
*/
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw, s->buf, s->cipherblk));
BPP_READ(s->buf, s->cipherblk);
if (s->in.cipher)
ssh2_cipher_decrypt(
@ -376,9 +374,8 @@ static void ssh2_bpp_handle_input(BinaryPacketProtocol *bpp)
/*
* Read and decrypt the remainder of the packet.
*/
crMaybeWaitUntilV(bufchain_try_fetch_consume(
s->bpp.in_raw, s->data + s->cipherblk,
s->packetlen + s->maclen - s->cipherblk));
BPP_READ(s->data + s->cipherblk,
s->packetlen + s->maclen - s->cipherblk);
/* Decrypt everything _except_ the MAC. */
if (s->in.cipher)