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authorDmitry Kasatkin <dmitry.kasatkin@intel.com>2013-01-18 23:56:39 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-27 20:47:43 -0800
commit9c5f1b49341154b579851425dabb32cb3aa9b5db (patch)
tree11801701b164fb0cf4d8d2782303eb254f150eb5
parentf2a010040e2c368a76f7ea0ed6533f5779cb6b4b (diff)
downloadlinux-linaro-stable-9c5f1b49341154b579851425dabb32cb3aa9b5db.tar.gz
evm: checking if removexattr is not a NULL
commit a67adb997419fb53540d4a4f79c6471c60bc69b6 upstream. The following lines of code produce a kernel oops. fd = socket(PF_FILE, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); fchmod(fd, 0666); [ 139.922364] BUG: unable to handle kernel NULL pointer dereference at (null) [ 139.924982] IP: [< (null)>] (null) [ 139.924982] *pde = 00000000 [ 139.924982] Oops: 0000 [#5] SMP [ 139.924982] Modules linked in: fuse dm_crypt dm_mod i2c_piix4 serio_raw evdev binfmt_misc button [ 139.924982] Pid: 3070, comm: acpid Tainted: G D 3.8.0-rc2-kds+ #465 Bochs Bochs [ 139.924982] EIP: 0060:[<00000000>] EFLAGS: 00010246 CPU: 0 [ 139.924982] EIP is at 0x0 [ 139.924982] EAX: cf5ef000 EBX: cf5ef000 ECX: c143d600 EDX: c15225f2 [ 139.924982] ESI: cf4d2a1c EDI: cf4d2a1c EBP: cc02df10 ESP: cc02dee4 [ 139.924982] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 139.924982] CR0: 80050033 CR2: 00000000 CR3: 0c059000 CR4: 000006d0 [ 139.924982] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 139.924982] DR6: ffff0ff0 DR7: 00000400 [ 139.924982] Process acpid (pid: 3070, ti=cc02c000 task=d7705340 task.ti=cc02c000) [ 139.924982] Stack: [ 139.924982] c1203c88 00000000 cc02def4 cf4d2a1c ae21eefa 471b60d5 1083c1ba c26a5940 [ 139.924982] e891fb5e 00000041 00000004 cc02df1c c1203964 00000000 cc02df4c c10e20c3 [ 139.924982] 00000002 00000000 00000000 22222222 c1ff2222 cf5ef000 00000000 d76efb08 [ 139.924982] Call Trace: [ 139.924982] [<c1203c88>] ? evm_update_evmxattr+0x5b/0x62 [ 139.924982] [<c1203964>] evm_inode_post_setattr+0x22/0x26 [ 139.924982] [<c10e20c3>] notify_change+0x25f/0x281 [ 139.924982] [<c10cbf56>] chmod_common+0x59/0x76 [ 139.924982] [<c10e27a1>] ? put_unused_fd+0x33/0x33 [ 139.924982] [<c10cca09>] sys_fchmod+0x39/0x5c [ 139.924982] [<c13f4f30>] syscall_call+0x7/0xb [ 139.924982] Code: Bad EIP value. This happens because sockets do not define the removexattr operation. Before removing the xattr, verify the removexattr function pointer is not NULL. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--security/integrity/evm/evm_crypto.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 49a464f..62fa2c5 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -205,9 +205,9 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM,
&xattr_data,
sizeof(xattr_data), 0);
- }
- else if (rc == -ENODATA)
+ } else if (rc == -ENODATA && inode->i_op->removexattr) {
rc = inode->i_op->removexattr(dentry, XATTR_NAME_EVM);
+ }
return rc;
}