From 6d1b02218a591ff95053b22c1ed802355e44878d Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 18 Jan 2022 22:39:08 +0100 Subject: [PATCH] xshared: Fix response to unprivileged users Expected behaviour in both variants is: * Print help without error, append extension help if -m and/or -j options are present * Indicate lack of permissions in an error message for anything else With iptables-nft, this was broken basically from day 1. Shared use of do_parse() then somewhat broke legacy: it started complaining about inability to create a lock file. Fix this by making iptables-nft assume extension revision 0 is present if permissions don't allow to verify. This is consistent with legacy. Second part is to exit directly after printing help - this avoids having to make the following code "nop-aware" to prevent privileged actions. Signed-off-by: Phil Sutter Reviewed-by: Florian Westphal (cherry picked from commit 26ecdf53960658771c0fc582f72a4025e2887f75) Conflicts: iptables/xshared.c -> Some chunks not applied as not necessary in RHEL8. --- iptables/nft.c | 5 ++ .../testcases/iptables/0008-unprivileged_0 | 60 +++++++++++++++++++ 2 files changed, 65 insertions(+) create mode 100755 iptables/tests/shell/testcases/iptables/0008-unprivileged_0 diff --git a/iptables/nft.c b/iptables/nft.c index dc5490c085364..c5cc6f83bf573 100644 --- a/iptables/nft.c +++ b/iptables/nft.c @@ -3110,6 +3110,11 @@ int nft_compatible_revision(const char *name, uint8_t rev, int opt) err: mnl_socket_close(nl); + /* pretend revision 0 is valid if not permitted to check - + * this is required for printing extension help texts as user */ + if (ret < 0 && errno == EPERM && rev == 0) + return 1; + return ret < 0 ? 0 : 1; } diff --git a/iptables/tests/shell/testcases/iptables/0008-unprivileged_0 b/iptables/tests/shell/testcases/iptables/0008-unprivileged_0 new file mode 100755 index 0000000000000..43e3bc8721dbd --- /dev/null +++ b/iptables/tests/shell/testcases/iptables/0008-unprivileged_0 @@ -0,0 +1,60 @@ +#!/bin/bash + +# iptables may print match/target specific help texts +# help output should work for unprivileged users + +run() { + echo "running: $*" >&2 + runuser -u nobody -- "$@" +} + +grep_or_rc() { + declare -g rc + grep -q "$*" && return 0 + echo "missing in output: $*" >&2 + return 1 +} + +out=$(run $XT_MULTI iptables --help) +let "rc+=$?" +grep_or_rc "iptables -h (print this help information)" <<< "$out" +let "rc+=$?" + +out=$(run $XT_MULTI iptables -m limit --help) +let "rc+=$?" +grep_or_rc "limit match options:" <<< "$out" +let "rc+=$?" + +out=$(run $XT_MULTI iptables -p tcp --help) +let "rc+=$?" +grep_or_rc "tcp match options:" <<< "$out" +let "rc+=$?" + +out=$(run $XT_MULTI iptables -j DNAT --help) +let "rc+=$?" +grep_or_rc "DNAT target options:" <<< "$out" +let "rc+=$?" + +out=$(run $XT_MULTI iptables -p tcp -j DNAT --help) +let "rc+=$?" +grep_or_rc "tcp match options:" <<< "$out" +let "rc+=$?" +out=$(run $XT_MULTI iptables -p tcp -j DNAT --help) +let "rc+=$?" +grep_or_rc "DNAT target options:" <<< "$out" +let "rc+=$?" + + +run $XT_MULTI iptables -L 2>&1 | \ + grep_or_rc "Permission denied" +let "rc+=$?" + +run $XT_MULTI iptables -A FORWARD -p tcp --dport 123 2>&1 | \ + grep_or_rc "Permission denied" +let "rc+=$?" + +run $XT_MULTI iptables -A FORWARD -j DNAT --to-destination 1.2.3.4 2>&1 | \ + grep_or_rc "Permission denied" +let "rc+=$?" + +exit $rc -- 2.34.1