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| author | Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr> | 2025-01-29 18:06:30 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-04 14:40:07 +0200 |
| commit | 3bb62cc3131d781ed7bac6a53cb88432409fdf90 (patch) | |
| tree | e75c9924e395d2dda0a1999f12d56894b1a2776d /net/netfilter | |
| parent | e563401934e41804ecd8ff2badba3edc93cb9bc5 (diff) | |
| download | linux-3bb62cc3131d781ed7bac6a53cb88432409fdf90.tar.gz linux-3bb62cc3131d781ed7bac6a53cb88432409fdf90.tar.bz2 linux-3bb62cc3131d781ed7bac6a53cb88432409fdf90.zip | |
netfilter: conntrack: Bound nf_conntrack sysctl writes
[ Upstream commit 8b6861390ffee6b8ed78b9395e3776c16fec6579 ]
nf_conntrack_max and nf_conntrack_expect_max sysctls were authorized to
be written any negative value, which would then be stored in the
unsigned int variables nf_conntrack_max and nf_ct_expect_max variables.
While the do_proc_dointvec_conv function is supposed to limit writing
handled by proc_dointvec proc_handler to INT_MAX. Such a negative value
being written in an unsigned int leads to a very high value, exceeding
this limit.
Moreover, the nf_conntrack_expect_max sysctl documentation specifies the
minimum value is 1.
The proc_handlers have thus been updated to proc_dointvec_minmax in
order to specify the following write bounds :
* Bound nf_conntrack_max sysctl writings between SYSCTL_ZERO
and SYSCTL_INT_MAX.
* Bound nf_conntrack_expect_max sysctl writings between SYSCTL_ONE
and SYSCTL_INT_MAX as defined in the sysctl documentation.
With this patch applied, sysctl writes outside the defined in the bound
will thus lead to a write error :
```
sysctl -w net.netfilter.nf_conntrack_expect_max=-1
sysctl: setting key "net.netfilter.nf_conntrack_expect_max": Invalid argument
```
Signed-off-by: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/nf_conntrack_standalone.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index 52245dbfae31..c333132e2079 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -631,7 +631,9 @@ static struct ctl_table nf_ct_sysctl_table[] = { .data = &nf_conntrack_max, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_INT_MAX, }, [NF_SYSCTL_CT_COUNT] = { .procname = "nf_conntrack_count", @@ -667,7 +669,9 @@ static struct ctl_table nf_ct_sysctl_table[] = { .data = &nf_ct_expect_max, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ONE, + .extra2 = SYSCTL_INT_MAX, }, [NF_SYSCTL_CT_ACCT] = { .procname = "nf_conntrack_acct", @@ -970,7 +974,9 @@ static struct ctl_table nf_ct_netfilter_table[] = { .data = &nf_conntrack_max, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_INT_MAX, }, { } }; |