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| author | Alexander Potapenko <glider@google.com> | 2017-04-25 18:51:46 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-25 14:05:52 -0400 |
| commit | fd2c83b35752f0a8236b976978ad4658df14a59f (patch) | |
| tree | c655f98ff56baaab4571e8eab59ab6d68fca67cd | |
| parent | 8048ced9beb21a52e3305f3332ae82020619f24e (diff) | |
| download | linux-fd2c83b35752f0a8236b976978ad4658df14a59f.tar.gz linux-fd2c83b35752f0a8236b976978ad4658df14a59f.tar.bz2 linux-fd2c83b35752f0a8236b976978ad4658df14a59f.zip | |
net/packet: check length in getsockopt() called with PACKET_HDRLEN
In the case getsockopt() is called with PACKET_HDRLEN and optlen < 4
|val| remains uninitialized and the syscall may behave differently
depending on its value, and even copy garbage to userspace on certain
architectures. To fix this we now return -EINVAL if optlen is too small.
This bug has been detected with KMSAN.
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/packet/af_packet.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 8489beff5c25..ea81ccf3c7d6 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3836,6 +3836,8 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, case PACKET_HDRLEN: if (len > sizeof(int)) len = sizeof(int); + if (len < sizeof(int)) + return -EINVAL; if (copy_from_user(&val, optval, len)) return -EFAULT; switch (val) { |