On Tue, 24 May 2022, rapier wrote:
> On 5/20/22 9:08 PM, Damien Miller wrote:
>
> > Are you sure that it's the packet receive buffer in this case?
> >
> > I'd recommend instrumenting sshbuf_read() first and seeing what what it's
> > doing, e.g. how much data the read() is returning.
> >
> > You can set SSHBUF_DEBUG at compile time to get a lot more info.
> > A strace or similar might be helpful too.
>
> So I tried this and I'm getting the following from the client
>
> rapier@iztli:~$ ssh -p2289 192.168.1.102
> kex_exchange_identification: No SSH version received in first 1024 lines from
> server
>
>
> Turns out the banner is getting filled with the SSHBUF_DBG lines:
> debug1: kex_exchange_identification: banner line 0: sshbuf.c:34
> sshbuf_check_sanity: sanity size 0 alloc 256 off 0 max 134217728
> debug1: kex_exchange_identification: banner line 1: sshbuf.c:354
> sshbuf_reserve: reserve buf = 0x556d1a798160 len = 3125
> debug1: kex_exchange_identification: banner line 2: sshbuf.c:309
> sshbuf_allocate: allocate buf = 0x556d1a798160 len = 3125
>
>
> Am I missing a step? This is with 9.0p1 with the default sshd_config. I've
> also tried it with 8.8 and 8.2 with the same results so I feel like I am
> missing something. Client is 8.2p1.
I forgot that it writes to stderr. Try this:
diff --git a/sshbuf-getput-basic.c b/sshbuf-getput-basic.c
index 15a56cb..f845ac6 100644
--- a/sshbuf-getput-basic.c
+++ b/sshbuf-getput-basic.c
@@ -194,7 +194,7 @@ sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)
return r;
if (valp != NULL) {
if ((*valp = malloc(len + 1)) == NULL) {
- SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
+ SSHBUF_DBG("SSH_ERR_ALLOC_FAIL");
return SSH_ERR_ALLOC_FAIL;
}
if (len != 0)
@@ -225,7 +225,7 @@ sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)
*lenp = len;
if (sshbuf_consume(buf, len + 4) != 0) {
/* Shouldn't happen */
- SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+ SSHBUF_DBG("SSH_ERR_INTERNAL_ERROR");
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
@@ -244,16 +244,16 @@ sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
if (lenp != NULL)
*lenp = 0;
if (sshbuf_len(buf) < 4) {
- SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
+ SSHBUF_DBG("SSH_ERR_MESSAGE_INCOMPLETE");
return SSH_ERR_MESSAGE_INCOMPLETE;
}
len = PEEK_U32(p);
if (len > SSHBUF_SIZE_MAX - 4) {
- SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));
+ SSHBUF_DBG("SSH_ERR_STRING_TOO_LARGE");
return SSH_ERR_STRING_TOO_LARGE;
}
if (sshbuf_len(buf) - 4 < len) {
- SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
+ SSHBUF_DBG("SSH_ERR_MESSAGE_INCOMPLETE");
return SSH_ERR_MESSAGE_INCOMPLETE;
}
if (valp != NULL)
@@ -279,14 +279,14 @@ sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)
/* Allow a \0 only at the end of the string */
if (len > 0 &&
(z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {
- SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));
+ SSHBUF_DBG("SSH_ERR_INVALID_FORMAT");
return SSH_ERR_INVALID_FORMAT;
}
if ((r = sshbuf_skip_string(buf)) != 0)
return -1;
if (valp != NULL) {
if ((*valp = malloc(len + 1)) == NULL) {
- SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
+ SSHBUF_DBG("SSH_ERR_ALLOC_FAIL");
return SSH_ERR_ALLOC_FAIL;
}
if (len != 0)
@@ -513,7 +513,7 @@ sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
int r;
if (len > SSHBUF_SIZE_MAX - 4) {
- SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
+ SSHBUF_DBG("SSH_ERR_NO_BUFFER_SPACE");
return SSH_ERR_NO_BUFFER_SPACE;
}
if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
@@ -571,7 +571,7 @@ sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
int r, prepend;
if (len > SSHBUF_SIZE_MAX - 5) {
- SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
+ SSHBUF_DBG("SSH_ERR_NO_BUFFER_SPACE");
return SSH_ERR_NO_BUFFER_SPACE;
}
/* Skip leading zero bytes */
@@ -621,7 +621,7 @@ sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
*lenp = len;
if (sshbuf_consume(buf, olen + 4) != 0) {
/* Shouldn't happen */
- SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+ SSHBUF_DBG("SSH_ERR_INTERNAL_ERROR");
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
diff --git a/sshbuf-getput-crypto.c b/sshbuf-getput-crypto.c
index e3e71ba..b22c1f3 100644
--- a/sshbuf-getput-crypto.c
+++ b/sshbuf-getput-crypto.c
@@ -78,7 +78,7 @@ sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
/* Skip string */
if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
/* Shouldn't happen */
- SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+ SSHBUF_DBG("SSH_ERR_INTERNAL_ERROR");
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
@@ -94,7 +94,7 @@ sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
size_t len;
if (pt == NULL) {
- SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
+ SSHBUF_DBG("SSH_ERR_ALLOC_FAIL");
return SSH_ERR_ALLOC_FAIL;
}
if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
@@ -113,7 +113,7 @@ sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
/* Skip string */
if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
/* Shouldn't happen */
- SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+ SSHBUF_DBG("SSH_ERR_INTERNAL_ERROR");
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
diff --git a/sshbuf.c b/sshbuf.c
index 8db22a0..685dbb8 100644
--- a/sshbuf.c
+++ b/sshbuf.c
@@ -39,7 +39,7 @@ sshbuf_check_sanity(const struct sshbuf *buf)
buf->size > buf->alloc ||
buf->off > buf->size)) {
/* Do not try to recover from corrupted buffer internals */
- SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+ SSHBUF_DBG("SSH_ERR_INTERNAL_ERROR");
ssh_signal(SIGSEGV, SIG_DFL);
raise(SIGSEGV);
return SSH_ERR_INTERNAL_ERROR;
@@ -50,7 +50,7 @@ sshbuf_check_sanity(const struct sshbuf *buf)
static void
sshbuf_maybe_pack(struct sshbuf *buf, int force)
{
- SSHBUF_DBG(("force %d", force));
+ SSHBUF_DBG("force %d", force);
SSHBUF_TELL("pre-pack");
if (buf->off == 0 || buf->readonly || buf->refcount > 1)
return;
@@ -221,7 +221,7 @@ sshbuf_set_max_size(struct sshbuf *buf, size_t max_size)
u_char *dp;
int r;
- SSHBUF_DBG(("set max buf = %p len = %zu", buf, max_size));
+ SSHBUF_DBG("set max buf = %p len = %zu", buf, max_size);
if ((r = sshbuf_check_sanity(buf)) != 0)
return r;
if (max_size == buf->max_size)
@@ -239,7 +239,7 @@ sshbuf_set_max_size(struct sshbuf *buf, size_t max_size)
rlen = ROUNDUP(buf->size, SSHBUF_SIZE_INC);
if (rlen > max_size)
rlen = max_size;
- SSHBUF_DBG(("new alloc = %zu", rlen));
+ SSHBUF_DBG("new alloc = %zu", rlen);
if ((dp = recallocarray(buf->d, buf->alloc, rlen, 1)) == NULL)
return SSH_ERR_ALLOC_FAIL;
buf->cd = buf->d = dp;
@@ -307,7 +307,7 @@ sshbuf_allocate(struct sshbuf *buf, size_t len)
u_char *dp;
int r;
- SSHBUF_DBG(("allocate buf = %p len = %zu", buf, len));
+ SSHBUF_DBG("allocate buf = %p len = %zu", buf, len);
if ((r = sshbuf_check_reserve(buf, len)) != 0)
return r;
/*
@@ -325,12 +325,12 @@ sshbuf_allocate(struct sshbuf *buf, size_t len)
*/
need = len + buf->size - buf->alloc;
rlen = ROUNDUP(buf->alloc + need, SSHBUF_SIZE_INC);
- SSHBUF_DBG(("need %zu initial rlen %zu", need, rlen));
+ SSHBUF_DBG("need %zu initial rlen %zu", need, rlen);
if (rlen > buf->max_size)
rlen = buf->alloc + need;
- SSHBUF_DBG(("adjusted rlen %zu", rlen));
+ SSHBUF_DBG("adjusted rlen %zu", rlen);
if ((dp = recallocarray(buf->d, buf->alloc, rlen, 1)) == NULL) {
- SSHBUF_DBG(("realloc fail"));
+ SSHBUF_DBG("realloc fail");
return SSH_ERR_ALLOC_FAIL;
}
buf->alloc = rlen;
@@ -352,7 +352,7 @@ sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp)
if (dpp != NULL)
*dpp = NULL;
- SSHBUF_DBG(("reserve buf = %p len = %zu", buf, len));
+ SSHBUF_DBG("reserve buf = %p len = %zu", buf, len);
if ((r = sshbuf_allocate(buf, len)) != 0)
return r;
@@ -368,7 +368,7 @@ sshbuf_consume(struct sshbuf *buf, size_t len)
{
int r;
- SSHBUF_DBG(("len = %zu", len));
+ SSHBUF_DBG("len = %zu", len);
if ((r = sshbuf_check_sanity(buf)) != 0)
return r;
if (len == 0)
@@ -388,7 +388,7 @@ sshbuf_consume_end(struct sshbuf *buf, size_t len)
{
int r;
- SSHBUF_DBG(("len = %zu", len));
+ SSHBUF_DBG("len = %zu", len);
if ((r = sshbuf_check_sanity(buf)) != 0)
return r;
if (len == 0)
diff --git a/sshbuf.h b/sshbuf.h
index 9624c43..cc3c34a 100644
--- a/sshbuf.h
+++ b/sshbuf.h
@@ -396,16 +396,17 @@ u_int sshbuf_refcount(const struct sshbuf *buf);
# ifdef SSHBUF_DEBUG
# define SSHBUF_TELL(what) do { \
- printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
+ fprintf(stderr, \
+ "%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
__FILE__, __LINE__, __func__, what, \
buf->size, buf->alloc, buf->off, buf->max_size); \
- fflush(stdout); \
+ fflush(stderr); \
} while (0)
-# define SSHBUF_DBG(x) do { \
- printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
- printf x; \
- printf("\n"); \
- fflush(stdout); \
+# define SSHBUF_DBG(...) do { \
+ fprintf(stderr, "%s:%d %s: ", __FILE__, __LINE__, __func__); \
+ fprintf(stderr, __VA_ARGS__); \
+ fprintf(stderr, "\n"); \
+ fflush(stderr); \
} while (0)
# else
# define SSHBUF_TELL(what)
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