Index: buffer.c =================================================================== RCS file: /var/cvs/openssh/buffer.c,v retrieving revision 1.26 diff -u -p -r1.26 buffer.c --- buffer.c 26 Mar 2006 03:24:49 -0000 1.26 +++ buffer.c 5 Apr 2006 02:30:16 -0000 @@ -18,6 +18,10 @@ #include "buffer.h" #include "log.h" +#define BUFFER_MAX_CHUNK 0x100000 +#define BUFFER_MAX_LEN 0xa00000 +#define BUFFER_ALLOCSZ 0x008000 + /* Initializes the buffer structure. */ void @@ -66,6 +70,23 @@ buffer_append(Buffer *buffer, const void memcpy(p, data, len); } +static int +buffer_compact(Buffer *buffer) +{ + /* + * If the buffer is quite empty, but all data is at the end, move the + * data to the beginning. + */ + if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { + memmove(buffer->buf, buffer->buf + buffer->offset, + buffer->end - buffer->offset); + buffer->end -= buffer->offset; + buffer->offset = 0; + return (1); + } + return (0); +} + /* * Appends space to the buffer, expanding the buffer if necessary. This does * not actually copy the data into the buffer, but instead returns a pointer @@ -93,20 +114,13 @@ restart: buffer->end += len; return p; } - /* - * If the buffer is quite empty, but all data is at the end, move the - * data to the beginning and retry. - */ - if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { - memmove(buffer->buf, buffer->buf + buffer->offset, - buffer->end - buffer->offset); - buffer->end -= buffer->offset; - buffer->offset = 0; + + /* Compact data back to the start of the buffer if necessary */ + if (buffer_compact(buffer)) goto restart; - } - /* Increase the size of the buffer and retry. */ - newlen = buffer->alloc + len + 32768; + /* Increase the size of the buffer and retry. */ + newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ); if (newlen > BUFFER_MAX_LEN) fatal("buffer_append_space: alloc %u not supported", newlen); @@ -114,6 +128,27 @@ restart: buffer->alloc = newlen; goto restart; /* NOTREACHED */ +} + +/* + * Check whether an allocation of 'len' will fit in the buffer + * This must follow the same math as buffer_append_space + */ +int +buffer_check_alloc(Buffer *buffer, u_int len) +{ + if (buffer->offset == buffer->end) { + buffer->offset = 0; + buffer->end = 0; + } + restart: + if (buffer->end + len < buffer->alloc) + return (1); + if (buffer_compact(buffer)) + goto restart; + if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) + return (1); + return (0); } /* Returns the number of bytes of data in the buffer. */ Index: buffer.h =================================================================== RCS file: /var/cvs/openssh/buffer.h,v retrieving revision 1.14 diff -u -p -r1.14 buffer.h --- buffer.h 26 Mar 2006 03:30:01 -0000 1.14 +++ buffer.h 4 Apr 2006 00:39:16 -0000 @@ -23,9 +23,6 @@ typedef struct { u_int end; /* Offset of last byte containing data. */ } Buffer; -#define BUFFER_MAX_CHUNK 0x100000 -#define BUFFER_MAX_LEN 0xa00000 - void buffer_init(Buffer *); void buffer_clear(Buffer *); void buffer_free(Buffer *); @@ -35,6 +32,8 @@ void *buffer_ptr(Buffer *); void buffer_append(Buffer *, const void *, u_int); void *buffer_append_space(Buffer *, u_int); + +int buffer_check_alloc(Buffer *, u_int); void buffer_get(Buffer *, void *, u_int); Index: channels.c =================================================================== RCS file: /var/cvs/openssh/channels.c,v retrieving revision 1.228 diff -u -p -r1.228 channels.c --- channels.c 31 Mar 2006 12:11:44 -0000 1.228 +++ channels.c 5 Apr 2006 02:30:36 -0000 @@ -747,12 +747,10 @@ channel_pre_open(Channel *c, fd_set *rea { u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); - /* check buffer limits */ - limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF)); - if (c->istate == CHAN_INPUT_OPEN && limit > 0 && - buffer_len(&c->input) < limit) + buffer_len(&c->input) < limit && + buffer_check_alloc(&c->input, CHAN_RBUF)) FD_SET(c->rfd, readset); if (c->ostate == CHAN_OUTPUT_OPEN || c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {