kernel_optimize_test/security/smack
Sabyrzhan Tasbolatov fa5b656092 smackfs: restrict bytes count in smackfs write functions
commit 7ef4c19d245f3dc233fd4be5acea436edd1d83d8 upstream.

syzbot found WARNINGs in several smackfs write operations where
bytes count is passed to memdup_user_nul which exceeds
GFP MAX_ORDER. Check count size if bigger than PAGE_SIZE.

Per smackfs doc, smk_write_net4addr accepts any label or -CIPSO,
smk_write_net6addr accepts any label or -DELETE. I couldn't find
any general rule for other label lengths except SMK_LABELLEN,
SMK_LONGLABEL, SMK_CIPSOMAX which are documented.

Let's constrain, in general, smackfs label lengths for PAGE_SIZE.
Although fuzzer crashes write to smackfs/netlabel on 0x400000 length.

Here is a quick way to reproduce the WARNING:
python -c "print('A' * 0x400000)" > /sys/fs/smackfs/netlabel

Reported-by: syzbot+a71a442385a0b2815497@syzkaller.appspotmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-07 12:34:05 +01:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
smack_access.c Smack: Handle io_uring kernel thread privileges 2020-12-30 11:54:02 +01:00
smack_lsm.c Smack LSM changes for Linux 5.10 2020-10-13 16:18:51 -07:00
smack_netfilter.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
smack.h Smack: Use the netlabel cache 2020-09-11 15:31:31 -07:00
smackfs.c smackfs: restrict bytes count in smackfs write functions 2021-03-07 12:34:05 +01:00