diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c index e18a4213d10c..1a9b27d5e256 100644 --- a/drivers/net/slip/slhc.c +++ b/drivers/net/slip/slhc.c @@ -80,9 +80,9 @@ #include static unsigned char *encode(unsigned char *cp, unsigned short n); -static long decode(unsigned char **cpp); +static long decode(unsigned char **cpp, const unsigned char *end); static unsigned char * put16(unsigned char *cp, unsigned short x); -static unsigned short pull16(unsigned char **cpp); +static long pull16(unsigned char **cpp, const unsigned char *end); /* Allocate compression data structure * slots must be in range 0 to 255 (zero meaning no compression) @@ -190,30 +190,34 @@ encode(unsigned char *cp, unsigned short n) return cp; } -/* Pull a 16-bit integer in host order from buffer in network byte order */ -static unsigned short -pull16(unsigned char **cpp) +/* Pull a 16-bit integer in host order from buffer in network byte order. + * Returns -1 if the buffer is exhausted, otherwise the 16-bit value. + */ +static long +pull16(unsigned char **cpp, const unsigned char *end) { - short rval; + long rval; + if (*cpp + 2 > end) + return -1; rval = *(*cpp)++; rval <<= 8; rval |= *(*cpp)++; return rval; } -/* Decode a number */ +/* Decode a number. Returns -1 if the buffer is exhausted. */ static long -decode(unsigned char **cpp) +decode(unsigned char **cpp, const unsigned char *end) { int x; + if (*cpp >= end) + return -1; x = *(*cpp)++; - if(x == 0){ - return pull16(cpp) & 0xffff; /* pull16 returns -1 on error */ - } else { - return x & 0xff; /* -1 if PULLCHAR returned error */ - } + if (x == 0) + return pull16(cpp, end); + return x & 0xff; } /* @@ -499,6 +503,7 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) struct cstate *cs; int len, hdrlen; unsigned char *cp = icp; + const unsigned char *end = icp + isize; /* We've got a compressed packet; read the change byte */ comp->sls_i_compressed++; @@ -536,6 +541,8 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) thp = &cs->cs_tcp; ip = &cs->cs_ip; + if (cp + 2 > end) + goto bad; thp->check = *(__sum16 *)cp; cp += 2; @@ -566,26 +573,26 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) default: if(changes & NEW_U){ thp->urg = 1; - if((x = decode(&cp)) == -1) { + if((x = decode(&cp, end)) == -1) { goto bad; } thp->urg_ptr = htons(x); } else thp->urg = 0; if(changes & NEW_W){ - if((x = decode(&cp)) == -1) { + if((x = decode(&cp, end)) == -1) { goto bad; } thp->window = htons( ntohs(thp->window) + x); } if(changes & NEW_A){ - if((x = decode(&cp)) == -1) { + if((x = decode(&cp, end)) == -1) { goto bad; } thp->ack_seq = htonl( ntohl(thp->ack_seq) + x); } if(changes & NEW_S){ - if((x = decode(&cp)) == -1) { + if((x = decode(&cp, end)) == -1) { goto bad; } thp->seq = htonl( ntohl(thp->seq) + x); @@ -593,7 +600,7 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) break; } if(changes & NEW_I){ - if((x = decode(&cp)) == -1) { + if((x = decode(&cp, end)) == -1) { goto bad; } ip->id = htons (ntohs (ip->id) + x);