rxrpc: fix some null-ptr-deref bugs in server_key.c
Some function calls are not implemented in rxrpc_no_security, there are
preparse_server_key, free_preparse_server_key and destroy_server_key.
When rxrpc security type is rxrpc_no_security, user can easily trigger a
null-ptr-deref bug via ioctl. So judgment should be added to prevent it
The crash log:
user@syzkaller:~$ ./rxrpc_preparse_s
[ 37.956878][T15626] BUG: kernel NULL pointer dereference, address:
0000000000000000
[ 37.957645][T15626] #PF: supervisor instruction fetch in kernel mode
[ 37.958229][T15626] #PF: error_code(0x0010) - not-present page
[ 37.958762][T15626] PGD
4aadf067 P4D
4aadf067 PUD
4aade067 PMD 0
[ 37.959321][T15626] Oops: 0010 [#1] PREEMPT SMP
[ 37.959739][T15626] CPU: 0 PID: 15626 Comm: rxrpc_preparse_ Not tainted 5.17.0-01442-gb47d5a4f6b8d #43
[ 37.960588][T15626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[ 37.961474][T15626] RIP: 0010:0x0
[ 37.961787][T15626] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
[ 37.962480][T15626] RSP: 0018:
ffffc9000d9abdc0 EFLAGS:
00010286
[ 37.963018][T15626] RAX:
ffffffff84335200 RBX:
ffff888012a1ce80 RCX:
0000000000000000
[ 37.963727][T15626] RDX:
0000000000000000 RSI:
ffffffff84a736dc RDI:
ffffc9000d9abe48
[ 37.964425][T15626] RBP:
ffffc9000d9abe48 R08:
0000000000000000 R09:
0000000000000002
[ 37.965118][T15626] R10:
000000000000000a R11:
f000000000000000 R12:
ffff888013145680
[ 37.965836][T15626] R13:
0000000000000000 R14:
ffffffffffffffec R15:
ffff8880432aba80
[ 37.966441][T15626] FS:
00007f2177907700(0000) GS:
ffff88803ec00000(0000) knlGS:
0000000000000000
[ 37.966979][T15626] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 37.967384][T15626] CR2:
ffffffffffffffd6 CR3:
000000004aaf1000 CR4:
00000000000006f0
[ 37.967864][T15626] Call Trace:
[ 37.968062][T15626] <TASK>
[ 37.968240][T15626] rxrpc_preparse_s+0x59/0x90
[ 37.968541][T15626] key_create_or_update+0x174/0x510
[ 37.968863][T15626] __x64_sys_add_key+0x139/0x1d0
[ 37.969165][T15626] do_syscall_64+0x35/0xb0
[ 37.969451][T15626] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 37.969824][T15626] RIP: 0033:0x43a1f9
Signed-off-by: Xiaolong Huang <butterflyhuangxx@gmail.com>
Tested-by: Xiaolong Huang <butterflyhuangxx@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-March/005069.html
Fixes:
12da59fcab5a ("rxrpc: Hand server key parsing off to the security class")
Link: https://lore.kernel.org/r/164865013439.2941502.8966285221215590921.stgit@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>