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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /security/integrity/ima/ima_appraise.c | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to 'security/integrity/ima/ima_appraise.c')
-rw-r--r-- | security/integrity/ima/ima_appraise.c | 797 |
1 files changed, 797 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c new file mode 100644 index 000000000..555342d33 --- /dev/null +++ b/security/integrity/ima/ima_appraise.c @@ -0,0 +1,797 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2011 IBM Corporation + * + * Author: + * Mimi Zohar <zohar@us.ibm.com> + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/xattr.h> +#include <linux/magic.h> +#include <linux/ima.h> +#include <linux/evm.h> +#include <linux/fsverity.h> +#include <keys/system_keyring.h> +#include <uapi/linux/fsverity.h> + +#include "ima.h" + +#ifdef CONFIG_IMA_APPRAISE_BOOTPARAM +static char *ima_appraise_cmdline_default __initdata; +core_param(ima_appraise, ima_appraise_cmdline_default, charp, 0); + +void __init ima_appraise_parse_cmdline(void) +{ + const char *str = ima_appraise_cmdline_default; + bool sb_state = arch_ima_get_secureboot(); + int appraisal_state = ima_appraise; + + if (!str) + return; + + if (strncmp(str, "off", 3) == 0) + appraisal_state = 0; + else if (strncmp(str, "log", 3) == 0) + appraisal_state = IMA_APPRAISE_LOG; + else if (strncmp(str, "fix", 3) == 0) + appraisal_state = IMA_APPRAISE_FIX; + else if (strncmp(str, "enforce", 7) == 0) + appraisal_state = IMA_APPRAISE_ENFORCE; + else + pr_err("invalid \"%s\" appraise option", str); + + /* If appraisal state was changed, but secure boot is enabled, + * keep its default */ + if (sb_state) { + if (!(appraisal_state & IMA_APPRAISE_ENFORCE)) + pr_info("Secure boot enabled: ignoring ima_appraise=%s option", + str); + } else { + ima_appraise = appraisal_state; + } +} +#endif + +/* + * is_ima_appraise_enabled - return appraise status + * + * Only return enabled, if not in ima_appraise="fix" or "log" modes. + */ +bool is_ima_appraise_enabled(void) +{ + return ima_appraise & IMA_APPRAISE_ENFORCE; +} + +/* + * ima_must_appraise - set appraise flag + * + * Return 1 to appraise or hash + */ +int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode, + int mask, enum ima_hooks func) +{ + u32 secid; + + if (!ima_appraise) + return 0; + + security_current_getsecid_subj(&secid); + return ima_match_policy(idmap, inode, current_cred(), secid, + func, mask, IMA_APPRAISE | IMA_HASH, NULL, + NULL, NULL, NULL); +} + +static int ima_fix_xattr(struct dentry *dentry, + struct integrity_iint_cache *iint) +{ + int rc, offset; + u8 algo = iint->ima_hash->algo; + + if (algo <= HASH_ALGO_SHA1) { + offset = 1; + iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST; + } else { + offset = 0; + iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG; + iint->ima_hash->xattr.ng.algo = algo; + } + rc = __vfs_setxattr_noperm(&nop_mnt_idmap, dentry, XATTR_NAME_IMA, + &iint->ima_hash->xattr.data[offset], + (sizeof(iint->ima_hash->xattr) - offset) + + iint->ima_hash->length, 0); + return rc; +} + +/* Return specific func appraised cached result */ +enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint, + enum ima_hooks func) +{ + switch (func) { + case MMAP_CHECK: + return iint->ima_mmap_status; + case BPRM_CHECK: + return iint->ima_bprm_status; + case CREDS_CHECK: + return iint->ima_creds_status; + case FILE_CHECK: + case POST_SETATTR: + return iint->ima_file_status; + case MODULE_CHECK ... MAX_CHECK - 1: + default: + return iint->ima_read_status; + } +} + +static void ima_set_cache_status(struct integrity_iint_cache *iint, + enum ima_hooks func, + enum integrity_status status) +{ + switch (func) { + case MMAP_CHECK: + iint->ima_mmap_status = status; + break; + case BPRM_CHECK: + iint->ima_bprm_status = status; + break; + case CREDS_CHECK: + iint->ima_creds_status = status; + break; + case FILE_CHECK: + case POST_SETATTR: + iint->ima_file_status = status; + break; + case MODULE_CHECK ... MAX_CHECK - 1: + default: + iint->ima_read_status = status; + break; + } +} + +static void ima_cache_flags(struct integrity_iint_cache *iint, + enum ima_hooks func) +{ + switch (func) { + case MMAP_CHECK: + iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED); + break; + case BPRM_CHECK: + iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED); + break; + case CREDS_CHECK: + iint->flags |= (IMA_CREDS_APPRAISED | IMA_APPRAISED); + break; + case FILE_CHECK: + case POST_SETATTR: + iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED); + break; + case MODULE_CHECK ... MAX_CHECK - 1: + default: + iint->flags |= (IMA_READ_APPRAISED | IMA_APPRAISED); + break; + } +} + +enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value, + int xattr_len) +{ + struct signature_v2_hdr *sig; + enum hash_algo ret; + + if (!xattr_value || xattr_len < 2) + /* return default hash algo */ + return ima_hash_algo; + + switch (xattr_value->type) { + case IMA_VERITY_DIGSIG: + sig = (typeof(sig))xattr_value; + if (sig->version != 3 || xattr_len <= sizeof(*sig) || + sig->hash_algo >= HASH_ALGO__LAST) + return ima_hash_algo; + return sig->hash_algo; + case EVM_IMA_XATTR_DIGSIG: + sig = (typeof(sig))xattr_value; + if (sig->version != 2 || xattr_len <= sizeof(*sig) + || sig->hash_algo >= HASH_ALGO__LAST) + return ima_hash_algo; + return sig->hash_algo; + case IMA_XATTR_DIGEST_NG: + /* first byte contains algorithm id */ + ret = xattr_value->data[0]; + if (ret < HASH_ALGO__LAST) + return ret; + break; + case IMA_XATTR_DIGEST: + /* this is for backward compatibility */ + if (xattr_len == 21) { + unsigned int zero = 0; + if (!memcmp(&xattr_value->data[16], &zero, 4)) + return HASH_ALGO_MD5; + else + return HASH_ALGO_SHA1; + } else if (xattr_len == 17) + return HASH_ALGO_MD5; + break; + } + + /* return default hash algo */ + return ima_hash_algo; +} + +int ima_read_xattr(struct dentry *dentry, + struct evm_ima_xattr_data **xattr_value, int xattr_len) +{ + int ret; + + ret = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_IMA, + (char **)xattr_value, xattr_len, GFP_NOFS); + if (ret == -EOPNOTSUPP) + ret = 0; + return ret; +} + +/* + * calc_file_id_hash - calculate the hash of the ima_file_id struct data + * @type: xattr type [enum evm_ima_xattr_type] + * @algo: hash algorithm [enum hash_algo] + * @digest: pointer to the digest to be hashed + * @hash: (out) pointer to the hash + * + * IMA signature version 3 disambiguates the data that is signed by + * indirectly signing the hash of the ima_file_id structure data. + * + * Signing the ima_file_id struct is currently only supported for + * IMA_VERITY_DIGSIG type xattrs. + * + * Return 0 on success, error code otherwise. + */ +static int calc_file_id_hash(enum evm_ima_xattr_type type, + enum hash_algo algo, const u8 *digest, + struct ima_digest_data *hash) +{ + struct ima_file_id file_id = { + .hash_type = IMA_VERITY_DIGSIG, .hash_algorithm = algo}; + unsigned int unused = HASH_MAX_DIGESTSIZE - hash_digest_size[algo]; + + if (type != IMA_VERITY_DIGSIG) + return -EINVAL; + + memcpy(file_id.hash, digest, hash_digest_size[algo]); + + hash->algo = algo; + hash->length = hash_digest_size[algo]; + + return ima_calc_buffer_hash(&file_id, sizeof(file_id) - unused, hash); +} + +/* + * xattr_verify - verify xattr digest or signature + * + * Verify whether the hash or signature matches the file contents. + * + * Return 0 on success, error code otherwise. + */ +static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, + struct evm_ima_xattr_data *xattr_value, int xattr_len, + enum integrity_status *status, const char **cause) +{ + struct ima_max_digest_data hash; + struct signature_v2_hdr *sig; + int rc = -EINVAL, hash_start = 0; + int mask; + + switch (xattr_value->type) { + case IMA_XATTR_DIGEST_NG: + /* first byte contains algorithm id */ + hash_start = 1; + fallthrough; + case IMA_XATTR_DIGEST: + if (*status != INTEGRITY_PASS_IMMUTABLE) { + if (iint->flags & IMA_DIGSIG_REQUIRED) { + if (iint->flags & IMA_VERITY_REQUIRED) + *cause = "verity-signature-required"; + else + *cause = "IMA-signature-required"; + *status = INTEGRITY_FAIL; + break; + } + clear_bit(IMA_DIGSIG, &iint->atomic_flags); + } else { + set_bit(IMA_DIGSIG, &iint->atomic_flags); + } + if (xattr_len - sizeof(xattr_value->type) - hash_start >= + iint->ima_hash->length) + /* + * xattr length may be longer. md5 hash in previous + * version occupied 20 bytes in xattr, instead of 16 + */ + rc = memcmp(&xattr_value->data[hash_start], + iint->ima_hash->digest, + iint->ima_hash->length); + else + rc = -EINVAL; + if (rc) { + *cause = "invalid-hash"; + *status = INTEGRITY_FAIL; + break; + } + *status = INTEGRITY_PASS; + break; + case EVM_IMA_XATTR_DIGSIG: + set_bit(IMA_DIGSIG, &iint->atomic_flags); + + mask = IMA_DIGSIG_REQUIRED | IMA_VERITY_REQUIRED; + if ((iint->flags & mask) == mask) { + *cause = "verity-signature-required"; + *status = INTEGRITY_FAIL; + break; + } + + sig = (typeof(sig))xattr_value; + if (sig->version >= 3) { + *cause = "invalid-signature-version"; + *status = INTEGRITY_FAIL; + break; + } + rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + (const char *)xattr_value, + xattr_len, + iint->ima_hash->digest, + iint->ima_hash->length); + if (rc == -EOPNOTSUPP) { + *status = INTEGRITY_UNKNOWN; + break; + } + if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc && + func == KEXEC_KERNEL_CHECK) + rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM, + (const char *)xattr_value, + xattr_len, + iint->ima_hash->digest, + iint->ima_hash->length); + if (rc) { + *cause = "invalid-signature"; + *status = INTEGRITY_FAIL; + } else { + *status = INTEGRITY_PASS; + } + break; + case IMA_VERITY_DIGSIG: + set_bit(IMA_DIGSIG, &iint->atomic_flags); + + if (iint->flags & IMA_DIGSIG_REQUIRED) { + if (!(iint->flags & IMA_VERITY_REQUIRED)) { + *cause = "IMA-signature-required"; + *status = INTEGRITY_FAIL; + break; + } + } + + sig = (typeof(sig))xattr_value; + if (sig->version != 3) { + *cause = "invalid-signature-version"; + *status = INTEGRITY_FAIL; + break; + } + + rc = calc_file_id_hash(IMA_VERITY_DIGSIG, iint->ima_hash->algo, + iint->ima_hash->digest, &hash.hdr); + if (rc) { + *cause = "sigv3-hashing-error"; + *status = INTEGRITY_FAIL; + break; + } + + rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + (const char *)xattr_value, + xattr_len, hash.digest, + hash.hdr.length); + if (rc) { + *cause = "invalid-verity-signature"; + *status = INTEGRITY_FAIL; + } else { + *status = INTEGRITY_PASS; + } + + break; + default: + *status = INTEGRITY_UNKNOWN; + *cause = "unknown-ima-data"; + break; + } + + return rc; +} + +/* + * modsig_verify - verify modsig signature + * + * Verify whether the signature matches the file contents. + * + * Return 0 on success, error code otherwise. + */ +static int modsig_verify(enum ima_hooks func, const struct modsig *modsig, + enum integrity_status *status, const char **cause) +{ + int rc; + + rc = integrity_modsig_verify(INTEGRITY_KEYRING_IMA, modsig); + if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc && + func == KEXEC_KERNEL_CHECK) + rc = integrity_modsig_verify(INTEGRITY_KEYRING_PLATFORM, + modsig); + if (rc) { + *cause = "invalid-signature"; + *status = INTEGRITY_FAIL; + } else { + *status = INTEGRITY_PASS; + } + + return rc; +} + +/* + * ima_check_blacklist - determine if the binary is blacklisted. + * + * Add the hash of the blacklisted binary to the measurement list, based + * on policy. + * + * Returns -EPERM if the hash is blacklisted. + */ +int ima_check_blacklist(struct integrity_iint_cache *iint, + const struct modsig *modsig, int pcr) +{ + enum hash_algo hash_algo; + const u8 *digest = NULL; + u32 digestsize = 0; + int rc = 0; + + if (!(iint->flags & IMA_CHECK_BLACKLIST)) + return 0; + + if (iint->flags & IMA_MODSIG_ALLOWED && modsig) { + ima_get_modsig_digest(modsig, &hash_algo, &digest, &digestsize); + + rc = is_binary_blacklisted(digest, digestsize); + if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) + process_buffer_measurement(&nop_mnt_idmap, NULL, digest, digestsize, + "blacklisted-hash", NONE, + pcr, NULL, false, NULL, 0); + } + + return rc; +} + +/* + * ima_appraise_measurement - appraise file measurement + * + * Call evm_verifyxattr() to verify the integrity of 'security.ima'. + * Assuming success, compare the xattr hash with the collected measurement. + * + * Return 0 on success, error code otherwise + */ +int ima_appraise_measurement(enum ima_hooks func, + struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename, + struct evm_ima_xattr_data *xattr_value, + int xattr_len, const struct modsig *modsig) +{ + static const char op[] = "appraise_data"; + const char *cause = "unknown"; + struct dentry *dentry = file_dentry(file); + struct inode *inode = d_backing_inode(dentry); + enum integrity_status status = INTEGRITY_UNKNOWN; + int rc = xattr_len; + bool try_modsig = iint->flags & IMA_MODSIG_ALLOWED && modsig; + + /* If not appraising a modsig, we need an xattr. */ + if (!(inode->i_opflags & IOP_XATTR) && !try_modsig) + return INTEGRITY_UNKNOWN; + + /* If reading the xattr failed and there's no modsig, error out. */ + if (rc <= 0 && !try_modsig) { + if (rc && rc != -ENODATA) + goto out; + + if (iint->flags & IMA_DIGSIG_REQUIRED) { + if (iint->flags & IMA_VERITY_REQUIRED) + cause = "verity-signature-required"; + else + cause = "IMA-signature-required"; + } else { + cause = "missing-hash"; + } + + status = INTEGRITY_NOLABEL; + if (file->f_mode & FMODE_CREATED) + iint->flags |= IMA_NEW_FILE; + if ((iint->flags & IMA_NEW_FILE) && + (!(iint->flags & IMA_DIGSIG_REQUIRED) || + (inode->i_size == 0))) + status = INTEGRITY_PASS; + goto out; + } + + status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, + rc < 0 ? 0 : rc, iint); + switch (status) { + case INTEGRITY_PASS: + case INTEGRITY_PASS_IMMUTABLE: + case INTEGRITY_UNKNOWN: + break; + case INTEGRITY_NOXATTRS: /* No EVM protected xattrs. */ + /* It's fine not to have xattrs when using a modsig. */ + if (try_modsig) + break; + fallthrough; + case INTEGRITY_NOLABEL: /* No security.evm xattr. */ + cause = "missing-HMAC"; + goto out; + case INTEGRITY_FAIL_IMMUTABLE: + set_bit(IMA_DIGSIG, &iint->atomic_flags); + cause = "invalid-fail-immutable"; + goto out; + case INTEGRITY_FAIL: /* Invalid HMAC/signature. */ + cause = "invalid-HMAC"; + goto out; + default: + WARN_ONCE(true, "Unexpected integrity status %d\n", status); + } + + if (xattr_value) + rc = xattr_verify(func, iint, xattr_value, xattr_len, &status, + &cause); + + /* + * If we have a modsig and either no imasig or the imasig's key isn't + * known, then try verifying the modsig. + */ + if (try_modsig && + (!xattr_value || xattr_value->type == IMA_XATTR_DIGEST_NG || + rc == -ENOKEY)) + rc = modsig_verify(func, modsig, &status, &cause); + +out: + /* + * File signatures on some filesystems can not be properly verified. + * When such filesystems are mounted by an untrusted mounter or on a + * system not willing to accept such a risk, fail the file signature + * verification. + */ + if ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) && + ((inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) || + (iint->flags & IMA_FAIL_UNVERIFIABLE_SIGS))) { + status = INTEGRITY_FAIL; + cause = "unverifiable-signature"; + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, + op, cause, rc, 0); + } else if (status != INTEGRITY_PASS) { + /* Fix mode, but don't replace file signatures. */ + if ((ima_appraise & IMA_APPRAISE_FIX) && !try_modsig && + (!xattr_value || + xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { + if (!ima_fix_xattr(dentry, iint)) + status = INTEGRITY_PASS; + } + + /* + * Permit new files with file/EVM portable signatures, but + * without data. + */ + if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE && + test_bit(IMA_DIGSIG, &iint->atomic_flags)) { + status = INTEGRITY_PASS; + } + + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, + op, cause, rc, 0); + } else { + ima_cache_flags(iint, func); + } + + ima_set_cache_status(iint, func, status); + return status; +} + +/* + * ima_update_xattr - update 'security.ima' hash value + */ +void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) +{ + struct dentry *dentry = file_dentry(file); + int rc = 0; + + /* do not collect and update hash for digital signatures */ + if (test_bit(IMA_DIGSIG, &iint->atomic_flags)) + return; + + if ((iint->ima_file_status != INTEGRITY_PASS) && + !(iint->flags & IMA_HASH)) + return; + + rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo, NULL); + if (rc < 0) + return; + + inode_lock(file_inode(file)); + ima_fix_xattr(dentry, iint); + inode_unlock(file_inode(file)); +} + +/** + * ima_inode_post_setattr - reflect file metadata changes + * @idmap: idmap of the mount the inode was found from + * @dentry: pointer to the affected dentry + * + * Changes to a dentry's metadata might result in needing to appraise. + * + * This function is called from notify_change(), which expects the caller + * to lock the inode's i_mutex. + */ +void ima_inode_post_setattr(struct mnt_idmap *idmap, + struct dentry *dentry) +{ + struct inode *inode = d_backing_inode(dentry); + struct integrity_iint_cache *iint; + int action; + + if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode) + || !(inode->i_opflags & IOP_XATTR)) + return; + + action = ima_must_appraise(idmap, inode, MAY_ACCESS, POST_SETATTR); + iint = integrity_iint_find(inode); + if (iint) { + set_bit(IMA_CHANGE_ATTR, &iint->atomic_flags); + if (!action) + clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); + } +} + +/* + * 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, int digsig) +{ + struct integrity_iint_cache *iint; + + if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)) + return; + + iint = integrity_iint_find(inode); + if (!iint) + return; + iint->measured_pcrs = 0; + set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags); + if (digsig) + set_bit(IMA_DIGSIG, &iint->atomic_flags); + else + clear_bit(IMA_DIGSIG, &iint->atomic_flags); +} + +/** + * validate_hash_algo() - Block setxattr with unsupported hash algorithms + * @dentry: object of the setxattr() + * @xattr_value: userland supplied xattr value + * @xattr_value_len: length of xattr_value + * + * The xattr value is mapped to its hash algorithm, and this algorithm + * must be built in the kernel for the setxattr to be allowed. + * + * Emit an audit message when the algorithm is invalid. + * + * Return: 0 on success, else an error. + */ +static int validate_hash_algo(struct dentry *dentry, + const struct evm_ima_xattr_data *xattr_value, + size_t xattr_value_len) +{ + char *path = NULL, *pathbuf = NULL; + enum hash_algo xattr_hash_algo; + const char *errmsg = "unavailable-hash-algorithm"; + unsigned int allowed_hashes; + + xattr_hash_algo = ima_get_hash_algo(xattr_value, xattr_value_len); + + allowed_hashes = atomic_read(&ima_setxattr_allowed_hash_algorithms); + + if (allowed_hashes) { + /* success if the algorithm is allowed in the ima policy */ + if (allowed_hashes & (1U << xattr_hash_algo)) + return 0; + + /* + * We use a different audit message when the hash algorithm + * is denied by a policy rule, instead of not being built + * in the kernel image + */ + errmsg = "denied-hash-algorithm"; + } else { + if (likely(xattr_hash_algo == ima_hash_algo)) + return 0; + + /* allow any xattr using an algorithm built in the kernel */ + if (crypto_has_alg(hash_algo_name[xattr_hash_algo], 0, 0)) + return 0; + } + + pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); + if (!pathbuf) + return -EACCES; + + path = dentry_path(dentry, pathbuf, PATH_MAX); + + integrity_audit_msg(AUDIT_INTEGRITY_DATA, d_inode(dentry), path, + "set_data", errmsg, -EACCES, 0); + + kfree(pathbuf); + + return -EACCES; +} + +int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + const struct evm_ima_xattr_data *xvalue = xattr_value; + int digsig = 0; + int result; + int err; + + result = ima_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); + if (result == 1) { + if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST)) + return -EINVAL; + + err = validate_hash_algo(dentry, xvalue, xattr_value_len); + if (err) + return err; + + digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG); + } else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) { + digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG); + } + if (result == 1 || evm_revalidate_status(xattr_name)) { + ima_reset_appraise_flags(d_backing_inode(dentry), digsig); + if (result == 1) + result = 0; + } + return result; +} + +int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) +{ + if (evm_revalidate_status(acl_name)) + ima_reset_appraise_flags(d_backing_inode(dentry), 0); + + return 0; +} + +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 || evm_revalidate_status(xattr_name)) { + ima_reset_appraise_flags(d_backing_inode(dentry), 0); + if (result == 1) + result = 0; + } + return result; +} |