kopia lustrzana https://gitlab.com/sane-project/backends
epson2: Rewrite network I/O
This addresses GHSL-2020-075 as well as all other problematic code uncovered as a result of investigating that. This includes: - buffer overflows due to use of unchecked lengths - integer overflows due to type conversions - potential memory leaks - checking for memory allocation failures Re #279.merge-requests/457/head
Olaf Meeuwissen
rodzic
e52a5bf719
commit
fff83e7eac
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@ -32,11 +32,12 @@
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#include "sane/sanei_debug.h"
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static int
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static ssize_t
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sanei_epson_net_read_raw(Epson_Scanner *s, unsigned char *buf, ssize_t wanted,
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SANE_Status *status)
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{
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int ready, read = -1;
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int ready;
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ssize_t read = -1;
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fd_set readable;
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struct timeval tv;
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@ -62,111 +63,136 @@ sanei_epson_net_read_raw(Epson_Scanner *s, unsigned char *buf, ssize_t wanted,
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return read;
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}
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int
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static ssize_t
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sanei_epson_net_read_buf(Epson_Scanner *s, unsigned char *buf, ssize_t wanted,
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SANE_Status * status)
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{
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ssize_t read = 0;
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DBG(23, "%s: reading up to %lu from buffer at %p, %lu available\n",
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__func__, (u_long) wanted, s->netptr, (u_long) s->netlen);
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if ((size_t) wanted > s->netlen) {
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*status = SANE_STATUS_IO_ERROR;
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wanted = s->netlen;
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}
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memcpy(buf, s->netptr, wanted);
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read = wanted;
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s->netptr += read;
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s->netlen -= read;
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if (s->netlen == 0) {
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DBG(23, "%s: freeing %p\n", __func__, s->netbuf);
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free(s->netbuf);
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s->netbuf = s->netptr = NULL;
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s->netlen = 0;
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}
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return read;
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}
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ssize_t
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sanei_epson_net_read(Epson_Scanner *s, unsigned char *buf, ssize_t wanted,
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SANE_Status * status)
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{
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ssize_t size;
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ssize_t read = 0;
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unsigned char header[12];
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/* read from buffer, if available */
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if (s->netptr != s->netbuf) {
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DBG(23, "reading %lu from buffer at %p, %lu available\n",
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(u_long) wanted, s->netptr, (u_long) s->netlen);
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memcpy(buf, s->netptr, wanted);
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read = wanted;
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s->netlen -= wanted;
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if (s->netlen == 0) {
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DBG(23, "%s: freeing %p\n", __func__, s->netbuf);
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free(s->netbuf);
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s->netbuf = s->netptr = NULL;
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s->netlen = 0;
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}
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return read;
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}
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/* receive net header */
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size = sanei_epson_net_read_raw(s, header, 12, status);
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if (size != 12) {
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if (wanted < 0) {
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*status = SANE_STATUS_INVAL;
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return 0;
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}
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size_t size;
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ssize_t read = 0;
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unsigned char header[12];
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/* read from remainder of buffer */
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if (s->netptr) {
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return sanei_epson_net_read_buf(s, buf, wanted, status);
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}
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/* receive net header */
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read = sanei_epson_net_read_raw(s, header, 12, status);
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if (read != 12) {
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return 0;
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}
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/* validate header */
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if (header[0] != 'I' || header[1] != 'S') {
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DBG(1, "header mismatch: %02X %02x\n", header[0], header[1]);
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*status = SANE_STATUS_IO_ERROR;
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return 0;
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}
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/* parse payload size */
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size = be32atoh(&header[6]);
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DBG(23, "%s: wanted = %lu, available = %lu\n", __func__,
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(u_long) wanted, (u_long) size);
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*status = SANE_STATUS_GOOD;
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if (size == wanted) {
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if (!s->netbuf) {
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DBG(15, "%s: direct read\n", __func__);
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DBG(23, "%s: wanted = %lu, available = %lu\n", __func__,
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(u_long) wanted, (u_long) size);
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DBG(15, "%s: full read\n", __func__);
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read = sanei_epson_net_read_raw(s, buf, size, status);
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if (s->netbuf) {
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free(s->netbuf);
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s->netbuf = NULL;
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s->netlen = 0;
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if ((size_t) wanted > size) {
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wanted = size;
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}
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if (read < 0) {
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return 0;
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}
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/* } else if (wanted < size && s->netlen == size) { */
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read = sanei_epson_net_read_raw(s, buf, wanted, status);
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} else {
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DBG(23, "%s: partial read\n", __func__);
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DBG(15, "%s: buffered read\n", __func__);
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DBG(23, "%s: bufferable = %lu, available = %lu\n", __func__,
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(u_long) s->netlen, (u_long) size);
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read = sanei_epson_net_read_raw(s, s->netbuf, size, status);
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if (read != size) {
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return 0;
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if (s->netlen > size) {
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s->netlen = size;
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}
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s->netlen = size - wanted;
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s->netptr += wanted;
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read = wanted;
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/* fill buffer */
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read = sanei_epson_net_read_raw(s, s->netbuf, s->netlen, status);
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s->netptr = s->netbuf;
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s->netlen = (read > 0 ? read : 0);
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DBG(23, "0,4 %02x %02x\n", s->netbuf[0], s->netbuf[4]);
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DBG(23, "storing %lu to buffer at %p, next read at %p, %lu bytes left\n",
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(u_long) size, s->netbuf, s->netptr, (u_long) s->netlen);
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memcpy(buf, s->netbuf, wanted);
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/* copy wanted part */
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read = sanei_epson_net_read_buf(s, buf, wanted, status);
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}
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return read;
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}
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int
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size_t
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sanei_epson_net_write(Epson_Scanner *s, unsigned int cmd, const unsigned char *buf,
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size_t buf_size, size_t reply_len, SANE_Status *status)
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{
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unsigned char *h1, *h2, *payload;
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unsigned char *packet = malloc(12 + 8 + buf_size);
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/* XXX check allocation failure */
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if (!packet) {
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*status = SANE_STATUS_NO_MEM;
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return 0;
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}
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h1 = packet;
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h2 = packet + 12;
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payload = packet + 12 + 8;
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if (reply_len) {
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s->netbuf = s->netptr = malloc(reply_len);
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if (s->netbuf) {
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DBG(23, "%s, freeing %p, %ld bytes unprocessed\n",
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__func__, s->netbuf, (u_long) s->netlen);
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free(s->netbuf);
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s->netbuf = s->netptr = NULL;
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s->netlen = 0;
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}
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s->netbuf = malloc(reply_len);
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if (!s->netbuf) {
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free(packet);
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*status = SANE_STATUS_NO_MEM;
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return 0;
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}
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s->netlen = reply_len;
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DBG(24, "allocated %lu bytes at %p\n",
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(u_long) reply_len, s->netbuf);
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DBG(24, "%s: allocated %lu bytes at %p\n", __func__,
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(u_long) s->netlen, s->netbuf);
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}
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DBG(24, "%s: cmd = %04x, buf = %p, buf_size = %lu, reply_len = %lu\n",
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@ -4,9 +4,9 @@
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#include <sys/types.h>
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#include "../include/sane/sane.h"
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extern int sanei_epson_net_read(struct Epson_Scanner *s, unsigned char *buf, ssize_t buf_size,
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extern ssize_t sanei_epson_net_read(struct Epson_Scanner *s, unsigned char *buf, ssize_t buf_size,
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SANE_Status *status);
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extern int sanei_epson_net_write(struct Epson_Scanner *s, unsigned int cmd, const unsigned char *buf,
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extern size_t sanei_epson_net_write(struct Epson_Scanner *s, unsigned int cmd, const unsigned char *buf,
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size_t buf_size, size_t reply_len,
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SANE_Status *status);
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extern SANE_Status sanei_epson_net_lock(struct Epson_Scanner *s);
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