This is a note to let you know that I've just added the patch titled

    sysfs: Fix memory leak in sysfs_sd_setsecdata().

to my driver-core git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to Linus's tree in the next big merge window after
the next kernel is released.

If you have any questions about this process, please let me know.


>From 93518dd2ebafcc761a8637b2877008cfd748c202 Mon Sep 17 00:00:00 2001
From: Masami Ichikawa <[email protected]>
Date: Tue, 21 Feb 2012 07:43:50 +0900
Subject: sysfs: Fix memory leak in sysfs_sd_setsecdata().

This patch fixies follwing two memory leak patterns that reported by kmemleak.
sysfs_sd_setsecdata() is called during sys_lsetxattr() operation.
It checks sd->s_iattr is NULL or not. Then if it is NULL, it calls
sysfs_init_inode_attrs() to allocate memory.
That code is this.

iattrs = sd->s_iattr;
if (!iattrs)
                iattrs = sysfs_init_inode_attrs(sd);

The iattrs recieves sysfs_init_inode_attrs()'s result,  but sd->s_iattr
doesn't know the address. so it needs to set correct address to
sd->s_iattr to free memory in other function.

unreferenced object 0xffff880250b73e60 (size 32):
  comm "systemd", pid 1, jiffies 4294683888 (age 94.553s)
  hex dump (first 32 bytes):
    73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
    72 3a 73 79 73 66 73 5f 74 3a 73 30 00 00 00 00  r:sysfs_t:s0....
  backtrace:
    [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98
    [<ffffffff811270ab>] __kmalloc+0x100/0x12c
    [<ffffffff8120775a>] context_struct_to_string+0x106/0x210
    [<ffffffff81207cc1>] security_sid_to_context_core+0x10b/0x129
    [<ffffffff812090ef>] security_sid_to_context+0x10/0x12
    [<ffffffff811fb0da>] selinux_inode_getsecurity+0x7d/0xa8
    [<ffffffff811fb127>] selinux_inode_getsecctx+0x22/0x2e
    [<ffffffff811f4d62>] security_inode_getsecctx+0x16/0x18
    [<ffffffff81191dad>] sysfs_setxattr+0x96/0x117
    [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9
    [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1
    [<ffffffff811544c6>] setxattr+0xcf/0x101
    [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f
    [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff88024163c5a0 (size 96):
  comm "systemd", pid 1, jiffies 4294683888 (age 94.553s)
  hex dump (first 32 bytes):
    00 00 00 00 ed 41 00 00 00 00 00 00 00 00 00 00  .....A..........
    00 00 00 00 00 00 00 00 0c 64 42 4f 00 00 00 00  .........dBO....
  backtrace:
    [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98
    [<ffffffff81127402>] kmem_cache_alloc_trace+0xc4/0xee
    [<ffffffff81191cbe>] sysfs_init_inode_attrs+0x2a/0x83
    [<ffffffff81191dd6>] sysfs_setxattr+0xbf/0x117
    [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9
    [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1
    [<ffffffff811544c6>] setxattr+0xcf/0x101
    [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f
    [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
`

Signed-off-by: Masami Ichikawa <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 fs/sysfs/inode.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 4291fd1..cc7ea5d 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -136,12 +136,13 @@ static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, 
void **secdata, u32 *sec
        void *old_secdata;
        size_t old_secdata_len;
 
-       iattrs = sd->s_iattr;
-       if (!iattrs)
-               iattrs = sysfs_init_inode_attrs(sd);
-       if (!iattrs)
-               return -ENOMEM;
+       if (!sd->s_iattr) {
+               sd->s_iattr = sysfs_init_inode_attrs(sd);
+               if (!sd->s_iattr)
+                       return -ENOMEM;
+       }
 
+       iattrs = sd->s_iattr;
        old_secdata = iattrs->ia_secdata;
        old_secdata_len = iattrs->ia_secdata_len;
 
-- 
1.7.9


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