diff options
author | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2011-03-10 18:54:15 -0500 |
---|---|---|
committer | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2012-09-07 14:57:47 -0400 |
commit | 42c63330f2b05aa6077c1bfc2798c04afe54f6b2 (patch) | |
tree | bbd7d212ba9c686b2b649718b8b919bdd2eecea4 /security/integrity | |
parent | 9957a5043e7b0b7361cdf48eea22b2900293e63a (diff) | |
download | linux-3.10-42c63330f2b05aa6077c1bfc2798c04afe54f6b2.tar.gz linux-3.10-42c63330f2b05aa6077c1bfc2798c04afe54f6b2.tar.bz2 linux-3.10-42c63330f2b05aa6077c1bfc2798c04afe54f6b2.zip |
ima: add ima_inode_setxattr/removexattr function and calls
Based on xattr_permission comments, the restriction to modify 'security'
xattr is left up to the underlying fs or lsm. Ensure that not just anyone
can modify or remove 'security.ima'.
Changelog v1:
- Unless IMA-APPRAISE is configured, use stub ima_inode_removexattr()/setxattr()
functions. (Moved ima_inode_removexattr()/setxattr() to ima_appraise.c)
Changelog:
- take i_mutex to fix locking (Dmitry Kasatkin)
- ima_reset_appraise_flags should only be called when modifying or
removing the 'security.ima' xattr. Requires CAP_SYS_ADMIN privilege.
(Incorporated fix from Roberto Sassu)
- Even if allowed to update security.ima, reset the appraisal flags,
forcing re-appraisal.
- Replace CAP_MAC_ADMIN with CAP_SYS_ADMIN
- static inline ima_inode_setxattr()/ima_inode_removexattr() stubs
- ima_protect_xattr should be static
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Diffstat (limited to 'security/integrity')
-rw-r--r-- | security/integrity/ima/ima_appraise.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 681cb6e7225..becc7e09116 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -169,3 +169,60 @@ void ima_inode_post_setattr(struct dentry *dentry) rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA); return; } + +/* + * ima_protect_xattr - protect 'security.ima' + * + * Ensure that not just anyone can modify or remove 'security.ima'. + */ +static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + return 1; + } + return 0; +} + +static void ima_reset_appraise_flags(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode)) + return; + + iint = integrity_iint_find(inode); + if (!iint) + return; + + iint->flags &= ~(IMA_COLLECTED | IMA_APPRAISED | IMA_MEASURED); + return; +} + +int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} + +int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, NULL, 0); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} |