diff options
Diffstat (limited to 'security/integrity/evm/evm_main.c')
| -rw-r--r-- | security/integrity/evm/evm_main.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index af9b6852f4e..3bcb80df4d0 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -14,6 +14,8 @@ * evm_inode_removexattr, and evm_verifyxattr */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/module.h> #include <linux/crypto.h> #include <linux/audit.h> @@ -30,7 +32,7 @@ static char *integrity_status_msg[] = { }; char *evm_hmac = "hmac(sha1)"; char *evm_hash = "sha1"; -int evm_hmac_version = CONFIG_EVM_HMAC_VERSION; +int evm_hmac_attrs; char *evm_config_xattrnames[] = { #ifdef CONFIG_SECURITY_SELINUX @@ -38,6 +40,11 @@ char *evm_config_xattrnames[] = { #endif #ifdef CONFIG_SECURITY_SMACK XATTR_NAME_SMACK, +#ifdef CONFIG_EVM_EXTRA_SMACK_XATTRS + XATTR_NAME_SMACKEXEC, + XATTR_NAME_SMACKTRANSMUTE, + XATTR_NAME_SMACKMMAP, +#endif #endif #ifdef CONFIG_IMA_APPRAISE XATTR_NAME_IMA, @@ -55,6 +62,14 @@ static int __init evm_set_fixmode(char *str) } __setup("evm=", evm_set_fixmode); +static void __init evm_init_config(void) +{ +#ifdef CONFIG_EVM_ATTR_FSUUID + evm_hmac_attrs |= EVM_ATTR_FSUUID; +#endif + pr_info("HMAC attrs: 0x%x\n", evm_hmac_attrs); +} + static int evm_find_protected_xattrs(struct dentry *dentry) { struct inode *inode = dentry->d_inode; @@ -62,7 +77,7 @@ static int evm_find_protected_xattrs(struct dentry *dentry) int error; int count = 0; - if (!inode->i_op || !inode->i_op->getxattr) + if (!inode->i_op->getxattr) return -EOPNOTSUPP; for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) { @@ -123,7 +138,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, goto out; } - xattr_len = rc - 1; + xattr_len = rc; /* check value type */ switch (xattr_data->type) { @@ -143,7 +158,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, if (rc) break; rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM, - xattr_data->digest, xattr_len, + (const char *)xattr_data, xattr_len, calc.digest, sizeof(calc.digest)); if (!rc) { /* we probably want to replace rsa with hmac here */ @@ -285,12 +300,20 @@ out: * @xattr_value: pointer to the new extended attribute value * @xattr_value_len: pointer to the new extended attribute value length * - * Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that - * the current value is valid. + * Before allowing the 'security.evm' protected xattr to be updated, + * verify the existing value is valid. As only the kernel should have + * access to the EVM encrypted key needed to calculate the HMAC, prevent + * userspace from writing HMAC value. Writing 'security.evm' requires + * requires CAP_SYS_ADMIN privileges. */ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) { + const struct evm_ima_xattr_data *xattr_data = xattr_value; + + if ((strcmp(xattr_name, XATTR_NAME_EVM) == 0) + && (xattr_data->type == EVM_XATTR_HMAC)) + return -EPERM; return evm_protect_xattr(dentry, xattr_name, xattr_value, xattr_value_len); } @@ -430,9 +453,11 @@ static int __init init_evm(void) { int error; + evm_init_config(); + error = evm_init_secfs(); if (error < 0) { - printk(KERN_INFO "EVM: Error registering secfs\n"); + pr_info("Error registering secfs\n"); goto err; } @@ -449,7 +474,7 @@ static int __init evm_display_config(void) char **xattrname; for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) - printk(KERN_INFO "EVM: %s\n", *xattrname); + pr_info("%s\n", *xattrname); return 0; } |