ksmbd: fix race condition with fp

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fp can used in each command. If smb2_close command is coming at the
same time, UAF issue can happen by race condition.

                           Time
                            +
Thread A                    | Thread B1 B2 .... B5
smb2_open                   | smb2_close
                            |
 __open_id                  |
   insert fp to file_table  |
                            |
                            |   atomic_dec_and_test(&fp->refcount)
                            |   if fp->refcount == 0, free fp by kfree.
 // UAF!                    |
 use fp                     |
                            +
This patch add f_state not to use freed fp is used and not to free fp in
use.

Reported-by: luosili <rootlab@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

...

This commit is contained in:

Namjae Jeon 2023-10-04 18:28:39 +09:00 • committed by Steve French

parent 53ff5cf891

commit 5a7ee91d11

3 changed files with 32 additions and 4 deletions

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4

fs/smb/server/smb2pdu.c

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23

fs/smb/server/vfs_cache.c

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9

fs/smb/server/vfs_cache.h

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