diff options
| author | Eric W. Biederman <ebiederm@maxwell.aristanetworks.com> | 2009-11-08 10:26:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-11 22:24:53 +0300 |
| commit | f44d3e7857e5d21413fc9a2b61948190c73705e7 (patch) | |
| tree | d93591de4747cd59e4ee8ba8dfe97867cbdad6fd | |
| parent | d3a3b0adad0865c12e39b712ca89efbd0a3a0dbc (diff) | |
| download | linux-f44d3e7857e5d21413fc9a2b61948190c73705e7.tar.xz | |
sysfs: Update sysfs_setxattr so it updates secdata under the sysfs_mutex
The sysfs_mutex is required to ensure updates are and will remain
atomic with respect to other inode iattr updates, that do not happen
through the filesystem.
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/sysfs/inode.c | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index e1443518398e..000bd9865004 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -123,23 +123,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) return error; } +static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len) +{ + struct sysfs_inode_attrs *iattrs; + void *old_secdata; + size_t old_secdata_len; + + iattrs = sd->s_iattr; + if (!iattrs) + iattrs = sysfs_init_inode_attrs(sd); + if (!iattrs) + return -ENOMEM; + + old_secdata = iattrs->ia_secdata; + old_secdata_len = iattrs->ia_secdata_len; + + iattrs->ia_secdata = *secdata; + iattrs->ia_secdata_len = *secdata_len; + + *secdata = old_secdata; + *secdata_len = old_secdata_len; + return 0; +} + int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct sysfs_dirent *sd = dentry->d_fsdata; - struct sysfs_inode_attrs *iattrs; void *secdata; int error; u32 secdata_len = 0; if (!sd) return -EINVAL; - if (!sd->s_iattr) - sd->s_iattr = sysfs_init_inode_attrs(sd); - if (!sd->s_iattr) - return -ENOMEM; - - iattrs = sd->s_iattr; if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; @@ -151,12 +167,13 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, &secdata, &secdata_len); if (error) goto out; - if (iattrs->ia_secdata) - security_release_secctx(iattrs->ia_secdata, - iattrs->ia_secdata_len); - iattrs->ia_secdata = secdata; - iattrs->ia_secdata_len = secdata_len; + mutex_lock(&sysfs_mutex); + error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len); + mutex_unlock(&sysfs_mutex); + + if (secdata) + security_release_secctx(secdata, secdata_len); } else return -EINVAL; out: |