rose: Add length checks to CALL_REQUEST parsing, CVE-2011-1493

[linux-flexiantxendom0-natty.git] / net / rose / rose_subr.c

diff --git a/net/rose/rose_subr.c b/net/rose/rose_subr.c
index 174d51c..f6c71ca 100644 (file)
--- 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)