| Message ID | 20180620163345.212776-1-jannh@google.com |
|---|---|
| State | Awaiting Upstream, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] netfilter: nf_log: fix uninit read in nf_log_proc_dostring | expand |
On Wed, Jun 20, 2018 at 06:33:45PM +0200, Jann Horn wrote: > When proc_dostring() is called with a non-zero offset in strict mode, it > doesn't just write to the ->data buffer, it also reads. Make sure it > doesn't read uninitialized data. Applied, thanks.
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c index 426457047578..2c47f9ec3511 100644 --- a/net/netfilter/nf_log.c +++ b/net/netfilter/nf_log.c @@ -424,6 +424,10 @@ static int nf_log_proc_dostring(struct ctl_table *table, int write, if (write) { struct ctl_table tmp = *table; + /* proc_dostring() can append to existing strings, so we need to + * initialize it as an empty string. + */ + buf[0] = '\0'; tmp.data = buf; r = proc_dostring(&tmp, write, buffer, lenp, ppos); if (r)
When proc_dostring() is called with a non-zero offset in strict mode, it doesn't just write to the ->data buffer, it also reads. Make sure it doesn't read uninitialized data. Fixes: c6ac37d8d884 ("netfilter: nf_log: fix error on write NONE to [...]") Signed-off-by: Jann Horn <jannh@google.com> --- net/netfilter/nf_log.c | 4 ++++ 1 file changed, 4 insertions(+)