From: Brooke Basile brookebasile@gmail.com
commit 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52 upstream.
Some values extracted by ncm_unwrap_ntb() could possibly lead to several different out of bounds reads of memory. Specifically the values passed to netdev_alloc_skb_ip_align() need to be checked so that memory is not overflowed.
Resolve this by applying bounds checking to a number of different indexes and lengths of the structure parsing logic.
Reported-by: Ilja Van Sprundel ivansprundel@ioactive.com Signed-off-by: Brooke Basile brookebasile@gmail.com Acked-by: Felipe Balbi balbi@kernel.org Cc: stable stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/gadget/function/f_ncm.c | 81 ++++++++++++++++++++++++++++++------ 1 file changed, 69 insertions(+), 12 deletions(-)
--- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -1181,12 +1181,15 @@ static int ncm_unwrap_ntb(struct gether int ndp_index; unsigned dg_len, dg_len2; unsigned ndp_len; + unsigned block_len; struct sk_buff *skb2; int ret = -EINVAL; - unsigned max_size = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize); + unsigned ntb_max = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize); + unsigned frame_max = le16_to_cpu(ecm_desc.wMaxSegmentSize); const struct ndp_parser_opts *opts = ncm->parser_opts; unsigned crc_len = ncm->is_crc ? sizeof(uint32_t) : 0; int dgram_counter; + bool ndp_after_header;
/* dwSignature */ if (get_unaligned_le32(tmp) != opts->nth_sign) { @@ -1205,25 +1208,37 @@ static int ncm_unwrap_ntb(struct gether } tmp++; /* skip wSequence */
+ block_len = get_ncm(&tmp, opts->block_length); /* (d)wBlockLength */ - if (get_ncm(&tmp, opts->block_length) > max_size) { + if (block_len > ntb_max) { INFO(port->func.config->cdev, "OUT size exceeded\n"); goto err; }
ndp_index = get_ncm(&tmp, opts->ndp_index); + ndp_after_header = false;
/* Run through all the NDP's in the NTB */ do { - /* NCM 3.2 */ - if (((ndp_index % 4) != 0) && - (ndp_index < opts->nth_size)) { + /* + * NCM 3.2 + * dwNdpIndex + */ + if (((ndp_index % 4) != 0) || + (ndp_index < opts->nth_size) || + (ndp_index > (block_len - + opts->ndp_size))) { INFO(port->func.config->cdev, "Bad index: %#X\n", ndp_index); goto err; } + if (ndp_index == opts->nth_size) + ndp_after_header = true;
- /* walk through NDP */ + /* + * walk through NDP + * dwSignature + */ tmp = (void *)(skb->data + ndp_index); if (get_unaligned_le32(tmp) != ncm->ndp_sign) { INFO(port->func.config->cdev, "Wrong NDP SIGN\n"); @@ -1234,14 +1249,15 @@ static int ncm_unwrap_ntb(struct gether ndp_len = get_unaligned_le16(tmp++); /* * NCM 3.3.1 + * wLength * entry is 2 items * item size is 16/32 bits, opts->dgram_item_len * 2 bytes * minimal: struct usb_cdc_ncm_ndpX + normal entry + zero entry * Each entry is a dgram index and a dgram length. */ if ((ndp_len < opts->ndp_size - + 2 * 2 * (opts->dgram_item_len * 2)) - || (ndp_len % opts->ndplen_align != 0)) { + + 2 * 2 * (opts->dgram_item_len * 2)) || + (ndp_len % opts->ndplen_align != 0)) { INFO(port->func.config->cdev, "Bad NDP length: %#X\n", ndp_len); goto err; @@ -1258,8 +1274,21 @@ static int ncm_unwrap_ntb(struct gether
do { index = index2; + /* wDatagramIndex[0] */ + if ((index < opts->nth_size) || + (index > block_len - opts->dpe_size)) { + INFO(port->func.config->cdev, + "Bad index: %#X\n", index); + goto err; + } + dg_len = dg_len2; - if (dg_len < 14 + crc_len) { /* ethernet hdr + crc */ + /* + * wDatagramLength[0] + * ethernet hdr + crc or larger than max frame size + */ + if ((dg_len < 14 + crc_len) || + (dg_len > frame_max)) { INFO(port->func.config->cdev, "Bad dgram length: %#X\n", dg_len); goto err; @@ -1283,6 +1312,37 @@ static int ncm_unwrap_ntb(struct gether index2 = get_ncm(&tmp, opts->dgram_item_len); dg_len2 = get_ncm(&tmp, opts->dgram_item_len);
+ if (index2 == 0 || dg_len2 == 0) + break; + + /* wDatagramIndex[1] */ + if (ndp_after_header) { + if (index2 < opts->nth_size + opts->ndp_size) { + INFO(port->func.config->cdev, + "Bad index: %#X\n", index2); + goto err; + } + } else { + if (index2 < opts->nth_size + opts->dpe_size) { + INFO(port->func.config->cdev, + "Bad index: %#X\n", index2); + goto err; + } + } + if (index2 > block_len - opts->dpe_size) { + INFO(port->func.config->cdev, + "Bad index: %#X\n", index2); + goto err; + } + + /* wDatagramLength[1] */ + if ((dg_len2 < 14 + crc_len) || + (dg_len2 > frame_max)) { + INFO(port->func.config->cdev, + "Bad dgram length: %#X\n", dg_len); + goto err; + } + /* * Copy the data into a new skb. * This ensures the truesize is correct @@ -1299,9 +1359,6 @@ static int ncm_unwrap_ntb(struct gether ndp_len -= 2 * (opts->dgram_item_len * 2);
dgram_counter++; - - if (index2 == 0 || dg_len2 == 0) - break; } while (ndp_len > 2 * (opts->dgram_item_len * 2)); } while (ndp_index);