tls: make input buffer grow as needed
As it turns out, it goes only up to "inbuf_size:4608" for kernel.org - fixed 18kb buffer was x4 larger than necessary. Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
9731ca7611
commit
3916139ac4
132
networking/tls.c
132
networking/tls.c
@ -181,6 +181,42 @@ enum {
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OUTBUF_PFX = 8 + AES_BLOCKSIZE, /* header + IV */
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OUTBUF_SFX = SHA256_OUTSIZE + AES_BLOCKSIZE, /* MAC + padding */
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MAX_OUTBUF = MAX_TLS_RECORD - OUTBUF_PFX - OUTBUF_SFX,
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// RFC 5246
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// | 6.2.1. Fragmentation
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// | The record layer fragments information blocks into TLSPlaintext
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// | records carrying data in chunks of 2^14 bytes or less. Client
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// | message boundaries are not preserved in the record layer (i.e.,
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// | multiple client messages of the same ContentType MAY be coalesced
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// | into a single TLSPlaintext record, or a single message MAY be
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// | fragmented across several records)
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// |...
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// | length
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// | The length (in bytes) of the following TLSPlaintext.fragment.
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// | The length MUST NOT exceed 2^14.
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// |...
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// | 6.2.2. Record Compression and Decompression
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// |...
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// | Compression must be lossless and may not increase the content length
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// | by more than 1024 bytes. If the decompression function encounters a
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// | TLSCompressed.fragment that would decompress to a length in excess of
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// | 2^14 bytes, it MUST report a fatal decompression failure error.
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// |...
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// | length
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// | The length (in bytes) of the following TLSCompressed.fragment.
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// | The length MUST NOT exceed 2^14 + 1024.
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// |...
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// | 6.2.3. Record Payload Protection
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// | The encryption and MAC functions translate a TLSCompressed
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// | structure into a TLSCiphertext. The decryption functions reverse
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// | the process. The MAC of the record also includes a sequence
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// | number so that missing, extra, or repeated messages are
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// | detectable.
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// |...
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// | length
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// | The length (in bytes) of the following TLSCiphertext.fragment.
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// | The length MUST NOT exceed 2^14 + 2048.
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MAX_INBUF = (1 << 14) + 2048,
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};
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struct record_hdr {
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@ -218,36 +254,10 @@ typedef struct tls_state {
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int outbuf_size;
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uint8_t *outbuf;
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// RFC 5246
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// | 6.2.1. Fragmentation
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// | The record layer fragments information blocks into TLSPlaintext
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// | records carrying data in chunks of 2^14 bytes or less. Client
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// | message boundaries are not preserved in the record layer (i.e.,
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// | multiple client messages of the same ContentType MAY be coalesced
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// | into a single TLSPlaintext record, or a single message MAY be
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// | fragmented across several records)
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// |...
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// | length
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// | The length (in bytes) of the following TLSPlaintext.fragment.
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// | The length MUST NOT exceed 2^14.
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// |...
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// | 6.2.2. Record Compression and Decompression
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// |...
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// | Compression must be lossless and may not increase the content length
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// | by more than 1024 bytes. If the decompression function encounters a
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// | TLSCompressed.fragment that would decompress to a length in excess of
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// | 2^14 bytes, it MUST report a fatal decompression failure error.
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// |...
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// | length
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// | The length (in bytes) of the following TLSCompressed.fragment.
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// | The length MUST NOT exceed 2^14 + 1024.
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//
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// Since our buffer also contains 5-byte headers, make it a bit bigger:
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int insize;
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int tail;
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//needed?
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uint64_t align____;
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uint8_t inbuf[20*1024];
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int inbuf_size;
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int ofs_to_buffered;
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int buffered_size;
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uint8_t *inbuf;
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} tls_state_t;
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@ -483,10 +493,21 @@ static tls_state_t *new_tls_state(void)
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static void tls_error_die(tls_state_t *tls)
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{
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dump_tls_record(tls->inbuf, tls->insize + tls->tail);
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dump_tls_record(tls->inbuf, tls->ofs_to_buffered + tls->buffered_size);
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bb_error_msg_and_die("TODO: useful diagnostic about %p", tls);
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}
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#if 0 //UNUSED
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static void tls_free_inbuf(tls_state_t *tls)
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{
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if (tls->buffered_size == 0) {
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free(tls->inbuf);
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tls->inbuf_size = 0;
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tls->inbuf = NULL;
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}
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}
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#endif
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static void tls_free_outbuf(tls_state_t *tls)
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{
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free(tls->outbuf);
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@ -683,13 +704,13 @@ static void xwrite_and_update_handshake_hash(tls_state_t *tls, unsigned size)
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static int tls_has_buffered_record(tls_state_t *tls)
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{
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int buffered = tls->tail;
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int buffered = tls->buffered_size;
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struct record_hdr *xhdr;
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int rec_size;
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if (buffered < RECHDR_LEN)
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return 0;
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xhdr = (void*)(tls->inbuf + tls->insize);
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xhdr = (void*)(tls->inbuf + tls->ofs_to_buffered);
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rec_size = RECHDR_LEN + (0x100 * xhdr->len16_hi + xhdr->len16_lo);
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if (buffered < rec_size)
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return 0;
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@ -704,23 +725,25 @@ static int tls_xread_record(tls_state_t *tls)
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int target;
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again:
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dbg("insize:%u tail:%u\n", tls->insize, tls->tail);
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total = tls->tail;
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dbg("ofs_to_buffered:%u buffered_size:%u\n", tls->ofs_to_buffered, tls->buffered_size);
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total = tls->buffered_size;
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if (total != 0) {
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memmove(tls->inbuf, tls->inbuf + tls->insize, total);
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//dbg("<< remaining at %d [%d] ", tls->insize, total);
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memmove(tls->inbuf, tls->inbuf + tls->ofs_to_buffered, total);
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//dbg("<< remaining at %d [%d] ", tls->ofs_to_buffered, total);
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//dump_raw_in("<< %s\n", tls->inbuf, total);
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}
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errno = 0;
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target = sizeof(tls->inbuf);
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target = MAX_INBUF;
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for (;;) {
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if (total >= RECHDR_LEN && target == sizeof(tls->inbuf)) {
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int rem;
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if (total >= RECHDR_LEN && target == MAX_INBUF) {
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xhdr = (void*)tls->inbuf;
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target = RECHDR_LEN + (0x100 * xhdr->len16_hi + xhdr->len16_lo);
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if (target >= sizeof(tls->inbuf)) {
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if (target > MAX_INBUF) {
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/* malformed input (too long): yell and die */
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tls->tail = 0;
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tls->insize = total;
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tls->buffered_size = 0;
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tls->ofs_to_buffered = total;
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tls_error_die(tls);
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}
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/* can also check type/proto_maj/proto_min here */
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@ -732,12 +755,22 @@ static int tls_xread_record(tls_state_t *tls)
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/* if total >= target, we have a full packet (and possibly more)... */
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if (total - target >= 0)
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break;
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sz = safe_read(tls->fd, tls->inbuf + total, sizeof(tls->inbuf) - total);
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/* input buffer is grown only as needed */
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rem = tls->inbuf_size - total;
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if (rem == 0) {
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tls->inbuf_size += MAX_INBUF / 8;
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if (tls->inbuf_size > MAX_INBUF)
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tls->inbuf_size = MAX_INBUF;
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dbg("inbuf_size:%d\n", tls->inbuf_size);
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rem = tls->inbuf_size - total;
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tls->inbuf = xrealloc(tls->inbuf, tls->inbuf_size);
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}
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sz = safe_read(tls->fd, tls->inbuf + total, rem);
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if (sz <= 0) {
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if (sz == 0 && total == 0) {
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/* "Abrupt" EOF, no TLS shutdown (seen from kernel.org) */
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dbg("EOF (without TLS shutdown) from peer\n");
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tls->tail = 0;
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tls->buffered_size = 0;
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goto end;
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}
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bb_perror_msg_and_die("short read, have only %d", total);
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@ -745,10 +778,10 @@ static int tls_xread_record(tls_state_t *tls)
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dump_raw_in("<< %s\n", tls->inbuf + total, sz);
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total += sz;
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}
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tls->tail = total - target;
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tls->insize = target;
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//dbg("<< stashing at %d [%d] ", tls->insize, tls->tail);
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//dump_hex("<< %s\n", tls->inbuf + tls->insize, tls->tail);
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tls->buffered_size = total - target;
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tls->ofs_to_buffered = target;
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//dbg("<< stashing at %d [%d] ", tls->ofs_to_buffered, tls->buffered_size);
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//dump_hex("<< %s\n", tls->inbuf + tls->ofs_to_buffered, tls->buffered_size);
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sz = target - RECHDR_LEN;
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@ -1547,7 +1580,7 @@ int tls_main(int argc UNUSED_PARAM, char **argv)
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* doubt it's ok to do it "raw"
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*/
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FD_CLR(STDIN_FILENO, &readfds);
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tls_free_outbuf(tls);
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tls_free_outbuf(tls); /* mem usage optimization */
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} else {
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if (nread == inbuf_size) {
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/* TLS has per record overhead, if input comes fast,
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@ -1570,6 +1603,7 @@ int tls_main(int argc UNUSED_PARAM, char **argv)
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*/
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//FD_CLR(cfd, &readfds);
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//close(STDOUT_FILENO);
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//tls_free_inbuf(tls); /* mem usage optimization */
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//continue;
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break;
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}
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