[PATCH 4.2 238/258] nfs/filelayout: Fix NULL reference caused by double freeing of fh_array

From: Greg Kroah-Hartman
Date: Sat Oct 17 2015 - 23:35:22 EST

4.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Kinglong Mee <kinglongmee@xxxxxxxxx>

commit 3ec0c97959abff33a42db9081c22132bcff5b4f2 upstream.

If filelayout_decode_layout fail, _filelayout_free_lseg will causes
a double freeing of fh_array.

[ 1179.279800] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 1179.280198] IP: [<ffffffffa027222d>] filelayout_free_fh_array.isra.11+0x1d/0x70 [nfs_layout_nfsv41_files]
[ 1179.281010] PGD 0
[ 1179.281443] Oops: 0000 [#1]
[ 1179.281831] Modules linked in: nfs_layout_nfsv41_files(OE) nfsv4(OE) nfs(OE) fscache(E) xfs libcrc32c coretemp nfsd crct10dif_pclmul ppdev crc32_pclmul crc32c_intel auth_rpcgss ghash_clmulni_intel nfs_acl lockd vmw_balloon grace sunrpc parport_pc vmw_vmci parport shpchp i2c_piix4 vmwgfx drm_kms_helper ttm drm serio_raw mptspi scsi_transport_spi mptscsih e1000 mptbase ata_generic pata_acpi [last unloaded: fscache]
[ 1179.283891] CPU: 0 PID: 13336 Comm: cat Tainted: G OE 4.3.0-rc1-pnfs+ #244
[ 1179.284323] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
[ 1179.285206] task: ffff8800501d48c0 ti: ffff88003e3c4000 task.ti: ffff88003e3c4000
[ 1179.285668] RIP: 0010:[<ffffffffa027222d>] [<ffffffffa027222d>] filelayout_free_fh_array.isra.11+0x1d/0x70 [nfs_layout_nfsv41_files]
[ 1179.286612] RSP: 0018:ffff88003e3c77f8 EFLAGS: 00010202
[ 1179.287092] RAX: 0000000000000000 RBX: ffff88001fe78900 RCX: 0000000000000000
[ 1179.287731] RDX: ffffea0000f40760 RSI: ffff88001fe789c8 RDI: ffff88001fe789c0
[ 1179.288383] RBP: ffff88003e3c7810 R08: ffffea0000f40760 R09: 0000000000000000
[ 1179.289170] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88001fe789c8
[ 1179.289959] R13: ffff88001fe789c0 R14: ffff88004ec05a80 R15: ffff88004f935b88
[ 1179.290791] FS: 00007f4e66bb5700(0000) GS:ffffffff81c29000(0000) knlGS:0000000000000000
[ 1179.291580] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1179.292209] CR2: 0000000000000000 CR3: 00000000203f8000 CR4: 00000000001406f0
[ 1179.292731] Stack:
[ 1179.293195] ffff88001fe78900 00000000000000d0 ffff88001fe78178 ffff88003e3c7868
[ 1179.293676] ffffffffa0272737 0000000000000001 0000000000000001 ffff88001fe78800
[ 1179.294151] 00000000614fffce ffffffff81727671 ffff88001fe78100 ffff88001fe78100
[ 1179.294623] Call Trace:
[ 1179.295092] [<ffffffffa0272737>] filelayout_alloc_lseg+0xa7/0x2d0 [nfs_layout_nfsv41_files]
[ 1179.295625] [<ffffffff81727671>] ? out_of_line_wait_on_bit+0x81/0xb0
[ 1179.296133] [<ffffffffa040407e>] pnfs_layout_process+0xae/0x320 [nfsv4]
[ 1179.296632] [<ffffffffa03e0a01>] nfs4_proc_layoutget+0x2b1/0x360 [nfsv4]
[ 1179.297134] [<ffffffffa0402983>] pnfs_update_layout+0x853/0xb30 [nfsv4]
[ 1179.297632] [<ffffffffa039db24>] ? nfs_get_lock_context+0x74/0x170 [nfs]
[ 1179.298158] [<ffffffffa0271807>] filelayout_pg_init_read+0x37/0x50 [nfs_layout_nfsv41_files]
[ 1179.298834] [<ffffffffa03a72d9>] __nfs_pageio_add_request+0x119/0x460 [nfs]
[ 1179.299385] [<ffffffffa03a6bd7>] ? nfs_create_request.part.9+0x37/0x2e0 [nfs]
[ 1179.299872] [<ffffffffa03a7cc3>] nfs_pageio_add_request+0xa3/0x1b0 [nfs]
[ 1179.300362] [<ffffffffa03a8635>] readpage_async_filler+0x85/0x260 [nfs]
[ 1179.300907] [<ffffffff81180cb1>] read_cache_pages+0x91/0xd0
[ 1179.301391] [<ffffffffa03a85b0>] ? nfs_read_completion+0x220/0x220 [nfs]
[ 1179.301867] [<ffffffffa03a8dc8>] nfs_readpages+0x128/0x200 [nfs]
[ 1179.302330] [<ffffffff81180ef3>] __do_page_cache_readahead+0x203/0x280
[ 1179.302784] [<ffffffff81180dc8>] ? __do_page_cache_readahead+0xd8/0x280
[ 1179.303413] [<ffffffff81181116>] ondemand_readahead+0x1a6/0x2f0
[ 1179.303855] [<ffffffff81181371>] page_cache_sync_readahead+0x31/0x50
[ 1179.304286] [<ffffffff811750a6>] generic_file_read_iter+0x4a6/0x5c0
[ 1179.304711] [<ffffffffa03a0316>] ? __nfs_revalidate_mapping+0x1f6/0x240 [nfs]
[ 1179.305132] [<ffffffffa039ccf2>] nfs_file_read+0x52/0xa0 [nfs]
[ 1179.305540] [<ffffffff811e343c>] __vfs_read+0xcc/0x100
[ 1179.305936] [<ffffffff811e3d15>] vfs_read+0x85/0x130
[ 1179.306326] [<ffffffff811e4a98>] SyS_read+0x58/0xd0
[ 1179.306708] [<ffffffff8172caaf>] entry_SYSCALL_64_fastpath+0x12/0x76
[ 1179.307094] Code: c4 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 8b 07 49 89 f4 85 c0 74 47 48 8b 06 49 89 fd <48> 8b 38 48 85 ff 74 22 31 db eb 0c 48 63 d3 48 8b 3c d0 48 85
[ 1179.308357] RIP [<ffffffffa027222d>] filelayout_free_fh_array.isra.11+0x1d/0x70 [nfs_layout_nfsv41_files]
[ 1179.309177] RSP <ffff88003e3c77f8>
[ 1179.309582] CR2: 0000000000000000

Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: William Dauchy <william@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/filelayout/filelayout.c | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)

--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -629,23 +629,18 @@ out_put:
goto out;
}

-static void filelayout_free_fh_array(struct nfs4_filelayout_segment *fl)
+static void _filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
{
int i;

- for (i = 0; i < fl->num_fh; i++) {
- if (!fl->fh_array[i])
- break;
- kfree(fl->fh_array[i]);
+ if (fl->fh_array) {
+ for (i = 0; i < fl->num_fh; i++) {
+ if (!fl->fh_array[i])
+ break;
+ kfree(fl->fh_array[i]);
+ }
+ kfree(fl->fh_array);
}
- kfree(fl->fh_array);
- fl->fh_array = NULL;
-}
-
-static void
-_filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
-{
- filelayout_free_fh_array(fl);
kfree(fl);
}

@@ -716,21 +711,21 @@ filelayout_decode_layout(struct pnfs_lay
/* Do we want to use a mempool here? */
fl->fh_array[i] = kmalloc(sizeof(struct nfs_fh), gfp_flags);
if (!fl->fh_array[i])
- goto out_err_free;
+ goto out_err;

p = xdr_inline_decode(&stream, 4);
if (unlikely(!p))
- goto out_err_free;
+ goto out_err;
fl->fh_array[i]->size = be32_to_cpup(p++);
if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
printk(KERN_ERR "NFS: Too big fh %d received %d\n",
i, fl->fh_array[i]->size);
- goto out_err_free;
+ goto out_err;
}

p = xdr_inline_decode(&stream, fl->fh_array[i]->size);
if (unlikely(!p))
- goto out_err_free;
+ goto out_err;
memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
dprintk("DEBUG: %s: fh len %d\n", __func__,
fl->fh_array[i]->size);
@@ -739,8 +734,6 @@ filelayout_decode_layout(struct pnfs_lay
__free_page(scratch);
return 0;

-out_err_free:
- filelayout_free_fh_array(fl);
out_err:
__free_page(scratch);
return -EIO;


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