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| author | Michal Kubecek <mkubecek@suse.cz> | 2020-12-08 23:13:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-12-21 13:28:17 +0100 |
| commit | d8d50009dadaa7f4d179af59e9796628c7487cf8 (patch) | |
| tree | f1efefc76cd324cd6e7cefc3b06f39fb3a055401 | |
| parent | 5c5d11d7a22e355655c61b7254e7d74cc51cb0fd (diff) | |
| download | linux-stable-d8d50009dadaa7f4d179af59e9796628c7487cf8.tar.gz linux-stable-d8d50009dadaa7f4d179af59e9796628c7487cf8.tar.bz2 linux-stable-d8d50009dadaa7f4d179af59e9796628c7487cf8.zip | |
ethtool: fix stack overflow in ethnl_parse_bitset()
[ Upstream commit a770bf515613c6e12ae904c3593e26016de99448 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 dae7402eaca3..2851f25b0af4 100644 --- a/net/ethtool/bitset.c +++ b/net/ethtool/bitset.c @@ -630,6 +630,8 @@ 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) |