From: Joas Antonio dos Santos ip_vs_ftp_get_addrport() accumulates decimal digits into a __u16 (hport) and into unsigned char (p[]) without checking for overflow. A crafted FTP PASV/EPSV response with an over-long port or address octet wraps the value, so the helper configures the data connection with a truncated port/address. The netfilter conntrack FTP helper had the same defect, fixed in commit 2b413fc689ba ("netfilter: nf_conntrack_ftp: avoid u16 overflows"). Apply the equivalent fix here: widen the port accumulator to u32 and reject values above 65535, and reject address octets above 255. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Joas Antonio dos Santos Acked-by: Julian Anastasov Signed-off-by: Pablo Neira Ayuso --- net/netfilter/ipvs/ip_vs_ftp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c index b315c608fda4..9e3e005a8263 100644 --- a/net/netfilter/ipvs/ip_vs_ftp.c +++ b/net/netfilter/ipvs/ip_vs_ftp.c @@ -102,7 +102,7 @@ static int ip_vs_ftp_get_addrport(char *data, char *data_limit, char *s, c; unsigned char p[6]; char edelim; - __u16 hport; + __u32 hport; int i = 0; if (data_limit - data < plen) { @@ -144,7 +144,11 @@ static int ip_vs_ftp_get_addrport(char *data, char *data_limit, return -1; c = *data; if (isdigit(c)) { - p[i] = p[i]*10 + c - '0'; + unsigned int val = p[i] * 10 + c - '0'; + + if (val > 255) + return -1; + p[i] = val; } else if (c == ',' && i < 5) { i++; p[i] = 0; @@ -222,6 +226,8 @@ static int ip_vs_ftp_get_addrport(char *data, char *data_limit, if (!isdigit(*s)) break; hport = hport * 10 + *s - '0'; + if (hport > 65535) + return -1; } if (s == data_limit || !hport || *s != edelim) return -1; -- 2.47.3