From: Ben Hutchings Date: Sun, 20 Mar 2011 06:48:05 +0000 (+0000) Subject: rose: Add length checks to CALL_REQUEST parsing X-Git-Tag: v3.12-rc1~6466^2~23 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e0bccd315db0c2f919e7fcf9cb60db21d9986f52;p=kernel%2Fkernel-generic.git rose: Add length checks to CALL_REQUEST parsing Define some constant offsets for CALL_REQUEST based on the description at and the definition of ROSE as using 10-digit (5-byte) addresses. Use them consistently. Validate all implicit and explicit facilities lengths. Validate the address length byte rather than either trusting or assuming its value. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- diff --git a/include/net/rose.h b/include/net/rose.h index 5ba9f02..555dd19 100644 --- a/include/net/rose.h +++ b/include/net/rose.h @@ -14,6 +14,12 @@ #define ROSE_MIN_LEN 3 +#define ROSE_CALL_REQ_ADDR_LEN_OFF 3 +#define ROSE_CALL_REQ_ADDR_LEN_VAL 0xAA /* each address is 10 digits */ +#define ROSE_CALL_REQ_DEST_ADDR_OFF 4 +#define ROSE_CALL_REQ_SRC_ADDR_OFF 9 +#define ROSE_CALL_REQ_FACILITIES_OFF 14 + #define ROSE_GFI 0x10 #define ROSE_Q_BIT 0x80 #define ROSE_D_BIT 0x40 @@ -214,7 +220,7 @@ extern void rose_requeue_frames(struct sock *); extern int rose_validate_nr(struct sock *, unsigned short); extern void rose_write_internal(struct sock *, int); extern int rose_decode(struct sk_buff *, int *, int *, int *, int *, int *); -extern int rose_parse_facilities(unsigned char *, struct rose_facilities_struct *); +extern int rose_parse_facilities(unsigned char *, unsigned int, struct rose_facilities_struct *); extern void rose_disconnect(struct sock *, int, int, int); /* rose_timer.c */ diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 5ee0c62..a80aef6 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -978,7 +978,7 @@ int rose_rx_call_request(struct sk_buff *skb, struct net_device *dev, struct ros struct sock *make; struct rose_sock *make_rose; struct rose_facilities_struct facilities; - int n, len; + int n; skb->sk = NULL; /* Initially we don't know who it's for */ @@ -987,9 +987,9 @@ int rose_rx_call_request(struct sk_buff *skb, struct net_device *dev, struct ros */ memset(&facilities, 0x00, sizeof(struct rose_facilities_struct)); - len = (((skb->data[3] >> 4) & 0x0F) + 1) >> 1; - len += (((skb->data[3] >> 0) & 0x0F) + 1) >> 1; - if (!rose_parse_facilities(skb->data + len + 4, &facilities)) { + if (!rose_parse_facilities(skb->data + ROSE_CALL_REQ_FACILITIES_OFF, + skb->len - ROSE_CALL_REQ_FACILITIES_OFF, + &facilities)) { rose_transmit_clear_request(neigh, lci, ROSE_INVALID_FACILITY, 76); return 0; } diff --git a/net/rose/rose_loopback.c b/net/rose/rose_loopback.c index ae4a9d9..3444562 100644 --- a/net/rose/rose_loopback.c +++ b/net/rose/rose_loopback.c @@ -73,9 +73,20 @@ static void rose_loopback_timer(unsigned long param) unsigned int lci_i, lci_o; while ((skb = skb_dequeue(&loopback_queue)) != NULL) { + if (skb->len < ROSE_MIN_LEN) { + kfree_skb(skb); + continue; + } lci_i = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF); frametype = skb->data[2]; - dest = (rose_address *)(skb->data + 4); + if (frametype == ROSE_CALL_REQUEST && + (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF || + skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] != + ROSE_CALL_REQ_ADDR_LEN_VAL)) { + kfree_skb(skb); + continue; + } + dest = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF); lci_o = ROSE_DEFAULT_MAXVC + 1 - lci_i; skb_reset_transport_header(skb); diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index 88a77e9..08dcd2f 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -861,7 +861,7 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) unsigned int lci, new_lci; unsigned char cause, diagnostic; struct net_device *dev; - int len, res = 0; + int res = 0; char buf[11]; #if 0 @@ -869,10 +869,17 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) return res; #endif + if (skb->len < ROSE_MIN_LEN) + return res; frametype = skb->data[2]; lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF); - src_addr = (rose_address *)(skb->data + 9); - dest_addr = (rose_address *)(skb->data + 4); + if (frametype == ROSE_CALL_REQUEST && + (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF || + skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] != + ROSE_CALL_REQ_ADDR_LEN_VAL)) + return res; + src_addr = (rose_address *)(skb->data + ROSE_CALL_REQ_SRC_ADDR_OFF); + dest_addr = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF); spin_lock_bh(&rose_neigh_list_lock); spin_lock_bh(&rose_route_list_lock); @@ -1010,12 +1017,11 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) goto out; } - len = (((skb->data[3] >> 4) & 0x0F) + 1) >> 1; - len += (((skb->data[3] >> 0) & 0x0F) + 1) >> 1; - memset(&facilities, 0x00, sizeof(struct rose_facilities_struct)); - if (!rose_parse_facilities(skb->data + len + 4, &facilities)) { + if (!rose_parse_facilities(skb->data + ROSE_CALL_REQ_FACILITIES_OFF, + skb->len - ROSE_CALL_REQ_FACILITIES_OFF, + &facilities)) { rose_transmit_clear_request(rose_neigh, lci, ROSE_INVALID_FACILITY, 76); goto out; } diff --git a/net/rose/rose_subr.c b/net/rose/rose_subr.c index 174d51c..f6c71ca 100644 --- a/net/rose/rose_subr.c +++ b/net/rose/rose_subr.c @@ -142,7 +142,7 @@ void rose_write_internal(struct sock *sk, int frametype) *dptr++ = ROSE_GFI | lci1; *dptr++ = lci2; *dptr++ = frametype; - *dptr++ = 0xAA; + *dptr++ = ROSE_CALL_REQ_ADDR_LEN_VAL; memcpy(dptr, &rose->dest_addr, ROSE_ADDR_LEN); dptr += ROSE_ADDR_LEN; memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN); @@ -246,12 +246,16 @@ static int rose_parse_national(unsigned char *p, struct rose_facilities_struct * do { switch (*p & 0xC0) { case 0x00: + if (len < 2) + return -1; p += 2; n += 2; len -= 2; break; case 0x40: + if (len < 3) + return -1; if (*p == FAC_NATIONAL_RAND) facilities->rand = ((p[1] << 8) & 0xFF00) + ((p[2] << 0) & 0x00FF); p += 3; @@ -260,32 +264,48 @@ static int rose_parse_national(unsigned char *p, struct rose_facilities_struct * break; case 0x80: + if (len < 4) + return -1; p += 4; n += 4; len -= 4; break; case 0xC0: + if (len < 2) + return -1; l = p[1]; + if (len < 2 + l) + return -1; if (*p == FAC_NATIONAL_DEST_DIGI) { if (!fac_national_digis_received) { + if (l < AX25_ADDR_LEN) + return -1; memcpy(&facilities->source_digis[0], p + 2, AX25_ADDR_LEN); facilities->source_ndigis = 1; } } else if (*p == FAC_NATIONAL_SRC_DIGI) { if (!fac_national_digis_received) { + if (l < AX25_ADDR_LEN) + return -1; memcpy(&facilities->dest_digis[0], p + 2, AX25_ADDR_LEN); facilities->dest_ndigis = 1; } } else if (*p == FAC_NATIONAL_FAIL_CALL) { + if (l < AX25_ADDR_LEN) + return -1; memcpy(&facilities->fail_call, p + 2, AX25_ADDR_LEN); } else if (*p == FAC_NATIONAL_FAIL_ADD) { + if (l < 1 + ROSE_ADDR_LEN) + return -1; memcpy(&facilities->fail_addr, p + 3, ROSE_ADDR_LEN); } else if (*p == FAC_NATIONAL_DIGIS) { + if (l % AX25_ADDR_LEN) + return -1; fac_national_digis_received = 1; facilities->source_ndigis = 0; facilities->dest_ndigis = 0; @@ -319,24 +339,32 @@ static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *fac do { switch (*p & 0xC0) { case 0x00: + if (len < 2) + return -1; p += 2; n += 2; len -= 2; break; case 0x40: + if (len < 3) + return -1; p += 3; n += 3; len -= 3; break; case 0x80: + if (len < 4) + return -1; p += 4; n += 4; len -= 4; break; case 0xC0: + if (len < 2) + return -1; l = p[1]; /* Prevent overflows*/ @@ -365,49 +393,44 @@ static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *fac return n; } -int rose_parse_facilities(unsigned char *p, +int rose_parse_facilities(unsigned char *p, unsigned packet_len, struct rose_facilities_struct *facilities) { int facilities_len, len; facilities_len = *p++; - if (facilities_len == 0) + if (facilities_len == 0 || (unsigned)facilities_len > packet_len) return 0; - while (facilities_len > 0) { - if (*p == 0x00) { - facilities_len--; - p++; - - switch (*p) { - case FAC_NATIONAL: /* National */ - len = rose_parse_national(p + 1, facilities, facilities_len - 1); - if (len < 0) - return 0; - facilities_len -= len + 1; - p += len + 1; - break; - - case FAC_CCITT: /* CCITT */ - len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1); - if (len < 0) - return 0; - facilities_len -= len + 1; - p += len + 1; - break; - - default: - printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p); - facilities_len--; - p++; - break; - } - } else - break; /* Error in facilities format */ + while (facilities_len >= 3 && *p == 0x00) { + facilities_len--; + p++; + + switch (*p) { + case FAC_NATIONAL: /* National */ + len = rose_parse_national(p + 1, facilities, facilities_len - 1); + break; + + case FAC_CCITT: /* CCITT */ + len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1); + break; + + default: + printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p); + len = 1; + break; + } + + if (len < 0) + return 0; + if (WARN_ON(len >= facilities_len)) + return 0; + facilities_len -= len + 1; + p += len + 1; } - return 1; + return facilities_len == 0; } static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose)