diff options
| author | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2011-08-11 01:22:30 -0400 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2011-09-14 15:24:51 -0400 |
| commit | a924ce0b35875ef9512135b46a32f4150fd700b2 (patch) | |
| tree | 0e01ac679790fe96c03b341b2670a2ed9c56a122 /security | |
| parent | fb88c2b6cbb1265a8bef60694699b37f5cd4ba76 (diff) | |
| download | lwn-a924ce0b35875ef9512135b46a32f4150fd700b2.tar.gz lwn-a924ce0b35875ef9512135b46a32f4150fd700b2.zip | |
evm: limit verifying current security.evm integrity
evm_protect_xattr unnecessarily validates the current security.evm
integrity, before updating non-evm protected extended attributes
and other file metadata. This patch limits validating the current
security.evm integrity to evm protected metadata.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/evm/evm_main.c | 58 |
1 files changed, 24 insertions, 34 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index f0127e536f84..7d4247535f9e 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -159,21 +159,6 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry, EXPORT_SYMBOL_GPL(evm_verifyxattr); /* - * evm_protect_xattr - protect the EVM extended attribute - * - * Prevent security.evm from being modified or removed. - */ -static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, - const void *xattr_value, size_t xattr_value_len) -{ - if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - } - return 0; -} - -/* * evm_verify_current_integrity - verify the dentry's metadata integrity * @dentry: pointer to the affected dentry * @@ -189,6 +174,26 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); } +/* + * evm_protect_xattr - protect the EVM extended attribute + * + * Prevent security.evm from being modified or removed. + */ +static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + enum integrity_status evm_status; + + if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + } else if (!evm_protected_xattr(xattr_name)) + return 0; + + evm_status = evm_verify_current_integrity(dentry); + return evm_status == INTEGRITY_PASS ? 0 : -EPERM; +} + /** * evm_inode_setxattr - protect the EVM extended attribute * @dentry: pointer to the affected dentry @@ -202,16 +207,8 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) { - - enum integrity_status evm_status; - int ret; - - ret = evm_protect_xattr(dentry, xattr_name, xattr_value, - xattr_value_len); - if (ret) - return ret; - evm_status = evm_verify_current_integrity(dentry); - return evm_status == INTEGRITY_PASS ? 0 : -EPERM; + return evm_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); } /** @@ -224,14 +221,7 @@ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, */ int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) { - enum integrity_status evm_status; - int ret; - - ret = evm_protect_xattr(dentry, xattr_name, NULL, 0); - if (ret) - return ret; - evm_status = evm_verify_current_integrity(dentry); - return evm_status == INTEGRITY_PASS ? 0 : -EPERM; + return evm_protect_xattr(dentry, xattr_name, NULL, 0); } /** @@ -286,7 +276,7 @@ int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) unsigned int ia_valid = attr->ia_valid; enum integrity_status evm_status; - if (ia_valid & ~(ATTR_MODE | ATTR_UID | ATTR_GID)) + if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) return 0; evm_status = evm_verify_current_integrity(dentry); return evm_status == INTEGRITY_PASS ? 0 : -EPERM; |