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| author | Michal Kubecek <mkubecek@suse.cz> | 2020-12-08 23:13:51 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2020-12-09 15:50:38 -0800 |
| commit | a770bf515613c6e12ae904c3593e26016de99448 (patch) | |
| tree | 070e9e0651e009cf87054dbdad0e7796b35fbb7c /net/ethtool | |
| parent | a379b01cd4b2aa3f12786b281a714871574e5ccb (diff) | |
| download | linux-a770bf515613c6e12ae904c3593e26016de99448.tar.bz2 | |
ethtool: fix stack overflow in ethnl_parse_bitset()
Syzbot reported a stack overflow in bitmap_from_arr32() called from
ethnl_parse_bitset() when bitset from netlink message is longer than
target bitmap length. While ethnl_compact_sanity_checks() makes sure that
trailing part is all zeros (i.e. the request does not try to touch bits
kernel does not recognize), we also need to cap change_bits to nbits so
that we don't try to write past the prepared bitmaps.
Fixes: 88db6d1e4f62 ("ethtool: add ethnl_parse_bitset() helper")
Reported-by: syzbot+9d39fa49d4df294aab93@syzkaller.appspotmail.com
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Link: https://lore.kernel.org/r/3487ee3a98e14cd526f55b6caaa959d2dcbcad9f.1607465316.git.mkubecek@suse.cz
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ethtool')
| -rw-r--r-- | net/ethtool/bitset.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c index 1fb3603d92ad..0515d6604b3b 100644 --- a/net/ethtool/bitset.c +++ b/net/ethtool/bitset.c @@ -628,6 +628,8 @@ int ethnl_parse_bitset(unsigned long *val, unsigned long *mask, return ret; change_bits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]); + if (change_bits > nbits) + change_bits = nbits; bitmap_from_arr32(val, nla_data(tb[ETHTOOL_A_BITSET_VALUE]), change_bits); if (change_bits < nbits) |