diff options
| author | David Dull <monderasdor@gmail.com> | 2026-03-07 21:26:21 +0300 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2026-03-10 16:10:42 +0300 |
| commit | cfe770220ac2dbd3e104c6b45094037455da81d4 (patch) | |
| tree | b49b7c5c4f34bea55f5d1fab58914cc71ea086d6 | |
| parent | d6d8cd2db236a9dd13dbc2d05843b3445cc964b5 (diff) | |
| download | linux-cfe770220ac2dbd3e104c6b45094037455da81d4.tar.xz | |
netfilter: x_tables: guard option walkers against 1-byte tail reads
When the last byte of options is a non-single-byte option kind, walkers
that advance with i += op[i + 1] ? : 1 can read op[i + 1] past the end
of the option area.
Add an explicit i == optlen - 1 check before dereferencing op[i + 1]
in xt_tcpudp and xt_dccp option walkers.
Fixes: 2e4e6a17af35 ("[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables")
Signed-off-by: David Dull <monderasdor@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
| -rw-r--r-- | net/netfilter/xt_dccp.c | 4 | ||||
| -rw-r--r-- | net/netfilter/xt_tcpudp.c | 6 |
2 files changed, 6 insertions, 4 deletions
diff --git a/net/netfilter/xt_dccp.c b/net/netfilter/xt_dccp.c index e5a13ecbe67a..037ab93e25d0 100644 --- a/net/netfilter/xt_dccp.c +++ b/net/netfilter/xt_dccp.c @@ -62,10 +62,10 @@ dccp_find_option(u_int8_t option, return true; } - if (op[i] < 2) + if (op[i] < 2 || i == optlen - 1) i++; else - i += op[i+1]?:1; + i += op[i + 1] ? : 1; } spin_unlock_bh(&dccp_buflock); diff --git a/net/netfilter/xt_tcpudp.c b/net/netfilter/xt_tcpudp.c index e8991130a3de..f76cf18f1a24 100644 --- a/net/netfilter/xt_tcpudp.c +++ b/net/netfilter/xt_tcpudp.c @@ -59,8 +59,10 @@ tcp_find_option(u_int8_t option, for (i = 0; i < optlen; ) { if (op[i] == option) return !invert; - if (op[i] < 2) i++; - else i += op[i+1]?:1; + if (op[i] < 2 || i == optlen - 1) + i++; + else + i += op[i + 1] ? : 1; } return invert; |