diff options
| author | Wyatt Feng <bronzed_45_vested@icloud.com> | 2026-07-03 13:04:46 +0800 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2026-07-03 14:45:21 +0200 |
| commit | 1b47026fb4b35bac850ad6e8a4ad7fc018e09ebc (patch) | |
| tree | d115783f8f335482b37511c066dc44ef46afad2c | |
| parent | 2975324d164c552b028632f107b567302863b7f6 (diff) | |
netfilter: xt_connmark: reject invalid shift parameters
Revision 2 of the CONNMARK target accepts user-controlled shift
parameters and applies them to 32-bit mark values in
connmark_tg_shift().
A shift_bits value of 32 or more triggers an undefined-shift bug when
the rule is evaluated. Invalid shift_dir values are also accepted and
silently fall back to the left-shift path.
Reject invalid revision-2 shift parameters in connmark_tg_check() so
malformed rules fail at installation time, before they can reach the
packet path.
Fixes: 472a73e00757 ("netfilter: xt_conntrack: Support bit-shifting for CONNMARK & MARK targets.")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Reviewed-by: Ren Wei <enjou1224z@gmail.com>
Reviewed-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
| -rw-r--r-- | net/netfilter/xt_connmark.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/net/netfilter/xt_connmark.c b/net/netfilter/xt_connmark.c index 4277084de2e7..2cf27f7d59b9 100644 --- a/net/netfilter/xt_connmark.c +++ b/net/netfilter/xt_connmark.c @@ -112,6 +112,16 @@ static int connmark_tg_check(const struct xt_tgchk_param *par) return ret; } +static int connmark_tg_check_v2(const struct xt_tgchk_param *par) +{ + const struct xt_connmark_tginfo2 *info = par->targinfo; + + if (info->shift_dir > D_SHIFT_RIGHT || info->shift_bits >= 32) + return -EINVAL; + + return connmark_tg_check(par); +} + static void connmark_tg_destroy(const struct xt_tgdtor_param *par) { nf_ct_netns_put(par->net, par->family); @@ -162,7 +172,7 @@ static struct xt_target connmark_tg_reg[] __read_mostly = { .name = "CONNMARK", .revision = 2, .family = NFPROTO_IPV4, - .checkentry = connmark_tg_check, + .checkentry = connmark_tg_check_v2, .target = connmark_tg_v2, .targetsize = sizeof(struct xt_connmark_tginfo2), .destroy = connmark_tg_destroy, @@ -183,7 +193,7 @@ static struct xt_target connmark_tg_reg[] __read_mostly = { .name = "CONNMARK", .revision = 2, .family = NFPROTO_IPV6, - .checkentry = connmark_tg_check, + .checkentry = connmark_tg_check_v2, .target = connmark_tg_v2, .targetsize = sizeof(struct xt_connmark_tginfo2), .destroy = connmark_tg_destroy, |