3.16.55-rc1 review patch. If anyone has any objections, please let me know.
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From: Håkon Bugge Haakon.Bugge@oracle.com
commit f3069c6d33f6ae63a1668737bc78aaaa51bff7ca upstream.
This is a fix for syzkaller719569, where memory registration was attempted without any underlying transport being loaded.
Analysis of the case reveals that it is the setsockopt() RDS_GET_MR (2) and RDS_GET_MR_FOR_DEST (7) that are vulnerable.
Here is an example stack trace when the bug is hit:
BUG: unable to handle kernel NULL pointer dereference at 00000000000000c0 IP: __rds_rdma_map+0x36/0x440 [rds] PGD 2f93d03067 P4D 2f93d03067 PUD 2f93d02067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: bridge stp llc tun rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache rds binfmt_misc sb_edac intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul c rc32_pclmul ghash_clmulni_intel pcbc aesni_intel crypto_simd glue_helper cryptd iTCO_wdt mei_me sg iTCO_vendor_support ipmi_si mei ipmi_devintf nfsd shpchp pcspkr i2c_i801 ioatd ma ipmi_msghandler wmi lpc_ich mfd_core auth_rpcgss nfs_acl lockd grace sunrpc ip_tables ext4 mbcache jbd2 mgag200 i2c_algo_bit drm_kms_helper ixgbe syscopyarea ahci sysfillrect sysimgblt libahci mdio fb_sys_fops ttm ptp libata sd_mod mlx4_core drm crc32c_intel pps_core megaraid_sas i2c_core dca dm_mirror dm_region_hash dm_log dm_mod CPU: 48 PID: 45787 Comm: repro_set2 Not tainted 4.14.2-3.el7uek.x86_64 #2 Hardware name: Oracle Corporation ORACLE SERVER X5-2L/ASM,MOBO TRAY,2U, BIOS 31110000 03/03/2017 task: ffff882f9190db00 task.stack: ffffc9002b994000 RIP: 0010:__rds_rdma_map+0x36/0x440 [rds] RSP: 0018:ffffc9002b997df0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff882fa2182580 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffc9002b997e40 RDI: ffff882fa2182580 RBP: ffffc9002b997e30 R08: 0000000000000000 R09: 0000000000000002 R10: ffff885fb29e3838 R11: 0000000000000000 R12: ffff882fa2182580 R13: ffff882fa2182580 R14: 0000000000000002 R15: 0000000020000ffc FS: 00007fbffa20b700(0000) GS:ffff882fbfb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 0000002f98a66006 CR4: 00000000001606e0 Call Trace: rds_get_mr+0x56/0x80 [rds] rds_setsockopt+0x172/0x340 [rds] ? __fget_light+0x25/0x60 ? __fdget+0x13/0x20 SyS_setsockopt+0x80/0xe0 do_syscall_64+0x67/0x1b0 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7fbff9b117f9 RSP: 002b:00007fbffa20aed8 EFLAGS: 00000293 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00000000000c84a4 RCX: 00007fbff9b117f9 RDX: 0000000000000002 RSI: 0000400000000114 RDI: 000000000000109b RBP: 00007fbffa20af10 R08: 0000000000000020 R09: 00007fbff9dd7860 R10: 0000000020000ffc R11: 0000000000000293 R12: 0000000000000000 R13: 00007fbffa20b9c0 R14: 00007fbffa20b700 R15: 0000000000000021
Code: 41 56 41 55 49 89 fd 41 54 53 48 83 ec 18 8b 87 f0 02 00 00 48 89 55 d0 48 89 4d c8 85 c0 0f 84 2d 03 00 00 48 8b 87 00 03 00 00 <48> 83 b8 c0 00 00 00 00 0f 84 25 03 00 0 0 48 8b 06 48 8b 56 08
The fix is to check the existence of an underlying transport in __rds_rdma_map().
Signed-off-by: Håkon Bugge haakon.bugge@oracle.com Reported-by: syzbot syzkaller@googlegroups.com Acked-by: Santosh Shilimkar santosh.shilimkar@oracle.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/rds/rdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -184,7 +184,7 @@ static int __rds_rdma_map(struct rds_soc long i; int ret;
- if (rs->rs_bound_addr == 0) { + if (rs->rs_bound_addr == 0 || !rs->rs_transport) { ret = -ENOTCONN; /* XXX not a great errno */ goto out; }