From e0bccd315db0c2f919e7fcf9cb60db21d9986f52 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Sun, 20 Mar 2011 06:48:05 +0000 Subject: 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 --- net/rose/rose_subr.c | 91 ++++++++++++++++++++++++++++++++-------------------- 1 file changed, 57 insertions(+), 34 deletions(-) (limited to 'net/rose/rose_subr.c') diff --git a/net/rose/rose_subr.c b/net/rose/rose_subr.c index 174d51c9ce37..f6c71caa94b9 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) -- cgit