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integrity-v6.8

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Merge tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:

 - Add a new IMA/EVM maintainer and reviewer

 - Disable EVM on overlayfs

   The EVM HMAC and the original file signatures contain filesystem
   specific metadata (e.g. i_ino, i_generation and s_uuid), preventing
   the security.evm xattr from directly being copied up to the overlay.
   Further before calculating and writing out the overlay file's EVM
   HMAC, EVM must first verify the existing backing file's
   'security.evm' value.

   For now until a solution is developed, disable EVM on overlayfs.

 - One bug fix and two cleanups

* tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  overlay: disable EVM
  evm: add support to disable EVM on unsupported filesystems
  evm: don't copy up 'security.evm' xattr
  MAINTAINERS: Add Eric Snowberg as a reviewer to IMA
  MAINTAINERS: Add Roberto Sassu as co-maintainer to IMA and EVM
  KEYS: encrypted: Add check for strsep
  ima: Remove EXPERIMENTAL from Kconfig
  ima: Reword IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
This commit is contained in:
Linus Torvalds 2024-01-09 13:24:06 -08:00
commit 6c1dd1fe5d
8 changed files with 62 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
MAINTAINERS
View File

@ -7930,6 +7930,7 @@ F: include/uapi/linux/ext4.h
Extended Verification Module (EVM)
M: Mimi Zohar <zohar@linux.ibm.com>
M: Roberto Sassu <roberto.sassu@huawei.com>
L: linux-integrity@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
@ -10518,7 +10519,9 @@ F: drivers/crypto/inside-secure/
INTEGRITY MEASUREMENT ARCHITECTURE (IMA)
M: Mimi Zohar <zohar@linux.ibm.com>
M: Roberto Sassu <roberto.sassu@huawei.com>
M: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
R: Eric Snowberg <eric.snowberg@oracle.com>
L: linux-integrity@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git

1
fs/overlayfs/super.c
View File

@ -1454,6 +1454,7 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
* lead to unexpected results.
*/
sb->s_iflags |= SB_I_NOUMASK;
sb->s_iflags |= SB_I_EVM_UNSUPPORTED;
err = -ENOMEM;
root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe);

6
include/linux/evm.h
View File

@ -31,6 +31,7 @@ extern void evm_inode_post_setxattr(struct dentry *dentry,
const char *xattr_name,
const void *xattr_value,
size_t xattr_value_len);
extern int evm_inode_copy_up_xattr(const char *name);
extern int evm_inode_removexattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *xattr_name);
extern void evm_inode_post_removexattr(struct dentry *dentry,
@ -117,6 +118,11 @@ static inline void evm_inode_post_setxattr(struct dentry *dentry,
return;
}
static inline int evm_inode_copy_up_xattr(const char *name)
{
return 0;
}
static inline int evm_inode_removexattr(struct mnt_idmap *idmap,
struct dentry *dentry,
const char *xattr_name)

1
include/linux/fs.h
View File

@ -1166,6 +1166,7 @@ extern int send_sigurg(struct fown_struct *fown);
#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */
#define SB_I_IMA_UNVERIFIABLE_SIGNATURE 0x00000020
#define SB_I_UNTRUSTED_MOUNTER 0x00000040
#define SB_I_EVM_UNSUPPORTED 0x00000080
#define SB_I_SKIP_SYNC 0x00000100 /* Skip superblock at global sync */
#define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */

42
security/integrity/evm/evm_main.c
View File

@ -151,6 +151,17 @@ static int evm_find_protected_xattrs(struct dentry *dentry)
return count;
}
static int is_unsupported_fs(struct dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
if (inode->i_sb->s_iflags & SB_I_EVM_UNSUPPORTED) {
pr_info_once("%s not supported\n", inode->i_sb->s_type->name);
return 1;
}
return 0;
}
/*
* evm_verify_hmac - calculate and compare the HMAC with the EVM xattr
*
@ -181,6 +192,9 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
iint->evm_status == INTEGRITY_PASS_IMMUTABLE))
return iint->evm_status;
if (is_unsupported_fs(dentry))
return INTEGRITY_UNKNOWN;
/* if status is not PASS, try to check again - against -ENOMEM */
/* first need to know the sig type */
@ -408,6 +422,9 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry,
if (!evm_key_loaded() || !evm_protected_xattr(xattr_name))
return INTEGRITY_UNKNOWN;
if (is_unsupported_fs(dentry))
return INTEGRITY_UNKNOWN;
if (!iint) {
iint = integrity_iint_find(d_backing_inode(dentry));
if (!iint)
@ -491,15 +508,21 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (is_unsupported_fs(dentry))
return -EPERM;
} else if (!evm_protected_xattr(xattr_name)) {
if (!posix_xattr_acl(xattr_name))
return 0;
if (is_unsupported_fs(dentry))
return 0;
evm_status = evm_verify_current_integrity(dentry);
if ((evm_status == INTEGRITY_PASS) ||
(evm_status == INTEGRITY_NOXATTRS))
return 0;
goto out;
}
} else if (is_unsupported_fs(dentry))
return 0;
evm_status = evm_verify_current_integrity(dentry);
if (evm_status == INTEGRITY_NOXATTRS) {
@ -750,6 +773,9 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
if (!(evm_initialized & EVM_INIT_HMAC))
return;
if (is_unsupported_fs(dentry))
return;
evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
}
@ -814,8 +840,12 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
if (evm_initialized & EVM_ALLOW_METADATA_WRITES)
return 0;
if (is_unsupported_fs(dentry))
return 0;
if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
return 0;
evm_status = evm_verify_current_integrity(dentry);
/*
* Writing attrs is safe for portable signatures, as portable signatures
@ -859,10 +889,20 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
if (!(evm_initialized & EVM_INIT_HMAC))
return;
if (is_unsupported_fs(dentry))
return;
if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
evm_update_evmxattr(dentry, NULL, NULL, 0);
}
int evm_inode_copy_up_xattr(const char *name)
{
if (strcmp(name, XATTR_NAME_EVM) == 0)
return 1; /* Discard */
return -EOPNOTSUPP;
}
/*
* evm_inode_init_security - initializes security.evm HMAC value
*/

10
security/integrity/ima/Kconfig
View File

@ -243,7 +243,7 @@ config IMA_APPRAISE_MODSIG
to accept such signatures.
config IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
bool "Permit keys validly signed by a built-in or secondary CA cert (EXPERIMENTAL)"
bool "Permit keys validly signed by a built-in, machine (if configured) or secondary"
depends on SYSTEM_TRUSTED_KEYRING
depends on SECONDARY_TRUSTED_KEYRING
depends on INTEGRITY_ASYMMETRIC_KEYS
@ -251,14 +251,14 @@ config IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
default n
help
Keys may be added to the IMA or IMA blacklist keyrings, if the
key is validly signed by a CA cert in the system built-in or
secondary trusted keyrings. The key must also have the
digitalSignature usage set.
key is validly signed by a CA cert in the system built-in,
machine (if configured), or secondary trusted keyrings. The
key must also have the digitalSignature usage set.
Intermediate keys between those the kernel has compiled in and the
IMA keys to be added may be added to the system secondary keyring,
provided they are validly signed by a key already resident in the
built-in or secondary trusted keyrings.
built-in, machine (if configured) or secondary trusted keyrings.
config IMA_BLACKLIST_KEYRING
bool "Create IMA machine owner blacklist keyrings (EXPERIMENTAL)"

4
security/keys/encrypted-keys/encrypted.c
View File

@ -237,6 +237,10 @@ static int datablob_parse(char *datablob, const char **format,
break;
}
*decrypted_data = strsep(&datablob, " \t");
if (!*decrypted_data) {
pr_info("encrypted_key: decrypted_data is missing\n");
break;
}
ret = 0;
break;
case Opt_load:

2
security/security.c
View File

@ -2623,7 +2623,7 @@ int security_inode_copy_up_xattr(const char *name)
return rc;
}
return LSM_RET_DEFAULT(inode_copy_up_xattr);
return evm_inode_copy_up_xattr(name);
}
EXPORT_SYMBOL(security_inode_copy_up_xattr);