BMC/Intel-BMC/linux.git/fs/nfsd, branch dev-4.17

nfsd: fix potential use-after-free in nfsd4_decode_getdeviceinfo

2018-08-03T05:47:34+00:00

[ Upstream commit 3171822fdcdd6e6d536047c425af6dc7a92dc585 ] When running a fuzz tester against a KASAN-enabled kernel, the following splat periodically occurs. The problem occurs when the test sends a GETDEVICEINFO request with a malformed xdr array (size but no data) for gdia_notify_types and the array size is > 0x3fffffff, which results in an overflow in the value of nbytes which is passed to read_buf(). If the array size is 0x40000000, 0x80000000, or 0xc0000000, then after the overflow occurs, the value of nbytes 0, and when that happens the pointer returned by read_buf() points to the end of the xdr data (i.e. argp->end) when really it should be returning NULL. Fix this by returning NFS4ERR_BAD_XDR if the array size is > 1000 (this value is arbitrary, but it's the same threshold used by nfsd4_decode_bitmap()... in could really be any value >= 1 since it's expected to get at most a single bitmap in gdia_notify_types). [ 119.256854] ================================================================== [ 119.257611] BUG: KASAN: use-after-free in nfsd4_decode_getdeviceinfo+0x5a4/0x5b0 [nfsd] [ 119.258422] Read of size 4 at addr ffff880113ada000 by task nfsd/538 [ 119.259146] CPU: 0 PID: 538 Comm: nfsd Not tainted 4.17.0+ #1 [ 119.259662] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014 [ 119.261202] Call Trace: [ 119.262265] dump_stack+0x71/0xab [ 119.263371] print_address_description+0x6a/0x270 [ 119.264609] kasan_report+0x258/0x380 [ 119.265854] ? nfsd4_decode_getdeviceinfo+0x5a4/0x5b0 [nfsd] [ 119.267291] nfsd4_decode_getdeviceinfo+0x5a4/0x5b0 [nfsd] [ 119.268549] ? nfs4svc_decode_compoundargs+0xa5b/0x13c0 [nfsd] [ 119.269873] ? nfsd4_decode_sequence+0x490/0x490 [nfsd] [ 119.271095] nfs4svc_decode_compoundargs+0xa5b/0x13c0 [nfsd] [ 119.272393] ? nfsd4_release_compoundargs+0x1b0/0x1b0 [nfsd] [ 119.273658] nfsd_dispatch+0x183/0x850 [nfsd] [ 119.274918] svc_process+0x161c/0x31a0 [sunrpc] [ 119.276172] ? svc_printk+0x190/0x190 [sunrpc] [ 119.277386] ? svc_xprt_release+0x451/0x680 [sunrpc] [ 119.278622] nfsd+0x2b9/0x430 [nfsd] [ 119.279771] ? nfsd_destroy+0x1c0/0x1c0 [nfsd] [ 119.281157] kthread+0x2db/0x390 [ 119.282347] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 119.283756] ret_from_fork+0x35/0x40 [ 119.286041] Allocated by task 436: [ 119.287525] kasan_kmalloc+0xa0/0xd0 [ 119.288685] kmem_cache_alloc+0xe9/0x1f0 [ 119.289900] get_empty_filp+0x7b/0x410 [ 119.291037] path_openat+0xca/0x4220 [ 119.292242] do_filp_open+0x182/0x280 [ 119.293411] do_sys_open+0x216/0x360 [ 119.294555] do_syscall_64+0xa0/0x2f0 [ 119.295721] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 119.298068] Freed by task 436: [ 119.299271] __kasan_slab_free+0x130/0x180 [ 119.300557] kmem_cache_free+0x78/0x210 [ 119.301823] rcu_process_callbacks+0x35b/0xbd0 [ 119.303162] __do_softirq+0x192/0x5ea [ 119.305443] The buggy address belongs to the object at ffff880113ada000 which belongs to the cache filp of size 256 [ 119.308556] The buggy address is located 0 bytes inside of 256-byte region [ffff880113ada000, ffff880113ada100) [ 119.311376] The buggy address belongs to the page: [ 119.312728] page:ffffea00044eb680 count:1 mapcount:0 mapping:0000000000000000 index:0xffff880113ada780 [ 119.314428] flags: 0x17ffe000000100(slab) [ 119.315740] raw: 0017ffe000000100 0000000000000000 ffff880113ada780 00000001000c0001 [ 119.317379] raw: ffffea0004553c60 ffffea00045c11e0 ffff88011b167e00 0000000000000000 [ 119.319050] page dumped because: kasan: bad access detected [ 119.321652] Memory state around the buggy address: [ 119.322993] ffff880113ad9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 119.324515] ffff880113ad9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 119.326087] >ffff880113ada000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 119.327547] ^ [ 119.328730] ffff880113ada080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 119.330218] ffff880113ada100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 119.331740] ================================================================== Signed-off-by: Scott Mayhew Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nfsd: fix error handling in nfs4_set_delegation()

2018-08-03T05:47:34+00:00

[ Upstream commit 692ad280bff3e81721ab138b9455948ab5289acf ] I noticed a memory corruption crash in nfsd in 4.17-rc1. This patch corrects the issue. Fix to return error if the delegation couldn't be hashed or there was a recall in progress. Use the existing error path instead of destroy_delegation() for readability. Signed-off-by: Andrew Elble Fixes: 353601e7d323c ("nfsd: create a separate lease for each delegation") Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nfsd: restrict rd_maxcount to svc_max_payload in nfsd_encode_readdir

2018-07-03T09:27:07+00:00

commit 9c2ece6ef67e9d376f32823086169b489c422ed0 upstream. nfsd4_readdir_rsize restricts rd_maxcount to svc_max_payload when estimating the size of the readdir reply, but nfsd_encode_readdir restricts it to INT_MAX when encoding the reply. This can result in log messages like "kernel: RPC request reserved 32896 but used 1049444". Restrict rd_dircount similarly (no reason it should be larger than svc_max_payload). Signed-off-by: Scott Mayhew Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

nfsd: vfs_mkdir() might succeed leaving dentry negative unhashed

2018-05-21T18:30:10+00:00

That can (and does, on some filesystems) happen - ->mkdir() (and thus vfs_mkdir()) can legitimately leave its argument negative and just unhash it, counting upon the lookup to pick the object we'd created next time we try to look at that name. Some vfs_mkdir() callers forget about that possibility... Acked-by: J. Bruce Fields Signed-off-by: Al Viro

nfsd: fix incorrect umasks

2018-04-03T20:27:08+00:00

We're neglecting to clear the umask after it's set, which can cause a later unrelated rpc to (incorrectly) use the same umask if it happens to be processed by the same thread. There's a more subtle problem here too: An NFSv4 compound request is decoded all in one pass before any operations are executed. Currently we're setting current->fs->umask at the time we decode the compound. In theory a single compound could contain multiple creates each setting a umask. In that case we'd end up using whichever umask was passed in the *last* operation as the umask for all the creates, whether that was correct or not. So, we should just be saving the umask at decode time and waiting to set it until we actually process the corresponding operation. In practice it's unlikely any client would do multiple creates in a single compound. And even if it did they'd likely be from the same process (hence carry the same umask). So this is a little academic, but we should get it right anyway. Fixes: 47057abde515 (nfsd: add support for the umask attribute) Cc: stable@vger.kernel.org Reported-by: Lucash Stach Signed-off-by: J. Bruce Fields

NFSD: Clean up legacy NFS SYMLINK argument XDR decoders

2018-04-03T19:08:16+00:00

Move common code in NFSD's legacy SYMLINK decoders into a helper. The immediate benefits include: - one fewer data copies on transports that support DDP - consistent error checking across all versions - reduction of code duplication - support for both legal forms of SYMLINK requests on RDMA transports for all versions of NFS (in particular, NFSv2, for completeness) In the long term, this helper is an appropriate spot to perform a per-transport call-out to fill the pathname argument using, say, RDMA Reads. Filling the pathname in the proc function also means that eventually the incoming filehandle can be interpreted so that filesystem- specific memory can be allocated as a sink for the pathname argument, rather than using anonymous pages. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

NFSD: Clean up legacy NFS WRITE argument XDR decoders

2018-04-03T19:08:16+00:00

Move common code in NFSD's legacy NFS WRITE decoders into a helper. The immediate benefit is reduction of code duplication and some nice micro-optimizations (see below). In the long term, this helper can perform a per-transport call-out to fill the rq_vec (say, using RDMA Reads). The legacy WRITE decoders and procs are changed to work like NFSv4, which constructs the rq_vec just before it is about to call vfs_writev. Why? Calling a transport call-out from the proc instead of the XDR decoder means that the incoming FH can be resolved to a particular filesystem and file. This would allow pages from the backing file to be presented to the transport to be filled, rather than presenting anonymous pages and copying or flipping them into the file's page cache later. I also prefer using the pages in rq_arg.pages, instead of pulling the data pages directly out of the rqstp::rq_pages array. This is currently the way the NFSv3 write decoder works, but the other two do not seem to take this approach. Fixing this removes the only reference to rq_pages found in NFSD, eliminating an NFSD assumption about how transports use the pages in rq_pages. Lastly, avoid setting up the first element of rq_vec as a zero- length buffer. This happens with an RDMA transport when a normal Read chunk is present because the data payload is in rq_arg's page list (none of it is in the head buffer). Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

nfsd: Trace NFSv4 COMPOUND execution

2018-04-03T19:08:15+00:00

This helps record the identity and timing of the ops in each NFSv4 COMPOUND, replacing dprintk calls that did much the same thing. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

nfsd: Add I/O trace points in the NFSv4 read proc

2018-04-03T19:08:15+00:00

NFSv4 read compound processing invokes nfsd_splice_read and nfs_readv directly, so the trace points currently in nfsd_read are not invoked for NFSv4 reads. Move the NFSD READ trace points to common helpers so that NFSv4 reads are captured. Also, record any local I/O error that occurs, the total count of bytes that were actually returned, and whether splice or vectored read was used. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

nfsd: Add I/O trace points in the NFSv4 write path

2018-04-03T19:08:15+00:00

NFSv4 write compound processing invokes nfsd_vfs_write directly. The trace points currently in nfsd_write are not effective for NFSv4 writes. Move the trace points into the shared nfsd_vfs_write() helper. After the I/O, we also want to record any local I/O error that might have occurred, and the total count of bytes that were actually moved (rather than the requested number). Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields