diff options
| -rw-r--r-- | fs/xattr.c | 14 | ||||
| -rw-r--r-- | include/linux/security.h | 11 | ||||
| -rw-r--r-- | security/dummy.c | 2 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 46 |
4 files changed, 49 insertions, 24 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index 3f9c64bea15..f6e00c0e114 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -143,7 +143,7 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) if (size) { if (size > XATTR_SIZE_MAX) size = XATTR_SIZE_MAX; - kvalue = kmalloc(size, GFP_KERNEL); + kvalue = kzalloc(size, GFP_KERNEL); if (!kvalue) return -ENOMEM; } @@ -154,11 +154,15 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) error = -EOPNOTSUPP; if (d->d_inode->i_op && d->d_inode->i_op->getxattr) error = d->d_inode->i_op->getxattr(d, kname, kvalue, size); - else if (!strncmp(kname, XATTR_SECURITY_PREFIX, - sizeof XATTR_SECURITY_PREFIX - 1)) { + + if (!strncmp(kname, XATTR_SECURITY_PREFIX, + sizeof XATTR_SECURITY_PREFIX - 1)) { const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1; - error = security_inode_getsecurity(d->d_inode, suffix, kvalue, - size); + int rv = security_inode_getsecurity(d->d_inode, suffix, kvalue, + size, error); + /* Security module active: overwrite error value */ + if (rv != -EOPNOTSUPP) + error = rv; } if (error > 0) { if (size && copy_to_user(value, kvalue, error)) diff --git a/include/linux/security.h b/include/linux/security.h index dac956ed98f..607ee209ea3 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -385,6 +385,9 @@ struct swap_info_struct; * NULL to request the size of the buffer required. @size indicates * the size of @buffer in bytes. Note that @name is the remainder * of the attribute name after the security. prefix has been removed. + * @err is the return value from the preceding fs getxattr call, + * and can be used by the security module to determine whether it + * should try and canonicalize the attribute value. * Return number of bytes used/required on success. * @inode_setsecurity: * Set the security label associated with @name for @inode from the @@ -1091,7 +1094,7 @@ struct security_operations { int (*inode_getxattr) (struct dentry *dentry, char *name); int (*inode_listxattr) (struct dentry *dentry); int (*inode_removexattr) (struct dentry *dentry, char *name); - int (*inode_getsecurity)(struct inode *inode, const char *name, void *buffer, size_t size); + int (*inode_getsecurity)(struct inode *inode, const char *name, void *buffer, size_t size, int err); int (*inode_setsecurity)(struct inode *inode, const char *name, const void *value, size_t size, int flags); int (*inode_listsecurity)(struct inode *inode, char *buffer, size_t buffer_size); @@ -1580,11 +1583,11 @@ static inline int security_inode_removexattr (struct dentry *dentry, char *name) return security_ops->inode_removexattr (dentry, name); } -static inline int security_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size) +static inline int security_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size, int err) { if (unlikely (IS_PRIVATE (inode))) return 0; - return security_ops->inode_getsecurity(inode, name, buffer, size); + return security_ops->inode_getsecurity(inode, name, buffer, size, err); } static inline int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -2222,7 +2225,7 @@ static inline int security_inode_removexattr (struct dentry *dentry, char *name) return cap_inode_removexattr(dentry, name); } -static inline int security_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size) +static inline int security_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size, int err) { return -EOPNOTSUPP; } diff --git a/security/dummy.c b/security/dummy.c index 3d34f3de7e8..2a0337a52d3 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -377,7 +377,7 @@ static int dummy_inode_removexattr (struct dentry *dentry, char *name) return 0; } -static int dummy_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size) +static int dummy_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size, int err) { return -EOPNOTSUPP; } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 8cd33b2cd86..d9ec85292e1 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2208,9 +2208,6 @@ static int selinux_inode_getxattr (struct dentry *dentry, char *name) struct inode *inode = dentry->d_inode; struct superblock_security_struct *sbsec = inode->i_sb->s_security; - if (sbsec->behavior == SECURITY_FS_USE_MNTPOINT) - return -EOPNOTSUPP; - return dentry_has_perm(current, NULL, dentry, FILE__GETATTR); } @@ -2241,33 +2238,54 @@ static int selinux_inode_removexattr (struct dentry *dentry, char *name) return -EACCES; } -static int selinux_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size) +/* + * Copy the in-core inode security context value to the user. If the + * getxattr() prior to this succeeded, check to see if we need to + * canonicalize the value to be finally returned to the user. + * + * Permission check is handled by selinux_inode_getxattr hook. + */ +static int selinux_inode_getsecurity(struct inode *inode, const char *name, void *buffer, size_t size, int err) { struct inode_security_struct *isec = inode->i_security; char *context; unsigned len; int rc; - /* Permission check handled by selinux_inode_getxattr hook.*/ - - if (strcmp(name, XATTR_SELINUX_SUFFIX)) - return -EOPNOTSUPP; + if (strcmp(name, XATTR_SELINUX_SUFFIX)) { + rc = -EOPNOTSUPP; + goto out; + } rc = security_sid_to_context(isec->sid, &context, &len); if (rc) - return rc; + goto out; + /* Probe for required buffer size */ if (!buffer || !size) { - kfree(context); - return len; + rc = len; + goto out_free; } + if (size < len) { - kfree(context); - return -ERANGE; + rc = -ERANGE; + goto out_free; + } + + if (err > 0) { + if ((len == err) && !(memcmp(context, buffer, len))) { + /* Don't need to canonicalize value */ + rc = err; + goto out_free; + } + memset(buffer, 0, size); } memcpy(buffer, context, len); + rc = len; +out_free: kfree(context); - return len; +out: + return rc; } static int selinux_inode_setsecurity(struct inode *inode, const char *name, |