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* evm: check xattr value length and type in evm_inode_setxattr()Dmitry Kasatkin2014-12-141-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3b1deef6b1289a99505858a3b212c5b50adf0c2f upstream. evm_inode_setxattr() can be called with no value. The function does not check the length so that following command can be used to produce the kernel oops: setfattr -n security.evm FOO. This patch fixes it. Changes in v3: * there is no reason to return different error codes for EVM_XATTR_HMAC and non EVM_XATTR_HMAC. Remove unnecessary test then. Changes in v2: * testing for validity of xattr type [ 1106.396921] BUG: unable to handle kernel NULL pointer dereference at (null) [ 1106.398192] IP: [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.399244] PGD 29048067 PUD 290d7067 PMD 0 [ 1106.399953] Oops: 0000 [#1] SMP [ 1106.400020] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse [ 1106.400020] CPU: 0 PID: 3635 Comm: setxattr Not tainted 3.16.0-kds+ #2936 [ 1106.400020] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 1106.400020] task: ffff8800291a0000 ti: ffff88002917c000 task.ti: ffff88002917c000 [ 1106.400020] RIP: 0010:[<ffffffff812af7b8>] [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.400020] RSP: 0018:ffff88002917fd50 EFLAGS: 00010246 [ 1106.400020] RAX: 0000000000000000 RBX: ffff88002917fdf8 RCX: 0000000000000000 [ 1106.400020] RDX: 0000000000000000 RSI: ffffffff818136d3 RDI: ffff88002917fdf8 [ 1106.400020] RBP: ffff88002917fd68 R08: 0000000000000000 R09: 00000000003ec1df [ 1106.400020] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800438a0a00 [ 1106.400020] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1106.400020] FS: 00007f7dfa7d7740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000 [ 1106.400020] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1106.400020] CR2: 0000000000000000 CR3: 000000003763e000 CR4: 00000000000006f0 [ 1106.400020] Stack: [ 1106.400020] ffff8800438a0a00 ffff88002917fdf8 0000000000000000 ffff88002917fd98 [ 1106.400020] ffffffff812a1030 ffff8800438a0a00 ffff88002917fdf8 0000000000000000 [ 1106.400020] 0000000000000000 ffff88002917fde0 ffffffff8116d08a ffff88002917fdc8 [ 1106.400020] Call Trace: [ 1106.400020] [<ffffffff812a1030>] security_inode_setxattr+0x5d/0x6a [ 1106.400020] [<ffffffff8116d08a>] vfs_setxattr+0x6b/0x9f [ 1106.400020] [<ffffffff8116d1e0>] setxattr+0x122/0x16c [ 1106.400020] [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45 [ 1106.400020] [<ffffffff8114d011>] ? __sb_start_write+0x10f/0x143 [ 1106.400020] [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45 [ 1106.400020] [<ffffffff811687c0>] ? __mnt_want_write+0x48/0x4f [ 1106.400020] [<ffffffff8116d3e6>] SyS_setxattr+0x6e/0xb0 [ 1106.400020] [<ffffffff81529da9>] system_call_fastpath+0x16/0x1b [ 1106.400020] Code: c3 0f 1f 44 00 00 55 48 89 e5 41 55 49 89 d5 41 54 49 89 fc 53 48 89 f3 48 c7 c6 d3 36 81 81 48 89 df e8 18 22 04 00 85 c0 75 07 <41> 80 7d 00 02 74 0d 48 89 de 4c 89 e7 e8 5a fe ff ff eb 03 83 [ 1106.400020] RIP [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.400020] RSP <ffff88002917fd50> [ 1106.400020] CR2: 0000000000000000 [ 1106.428061] ---[ end trace ae08331628ba3050 ]--- Reported-by: Jan Kara <jack@suse.cz> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* evm: prohibit userspace writing 'security.evm' HMAC valueMimi Zohar2014-07-111-2/+10
| | | | | | | | | | | | commit 2fb1c9a4f2dbc2f0bd2431c7fa64d0b5483864e4 upstream. Calculating the 'security.evm' HMAC value requires access to the EVM encrypted key. Only the kernel should have access to it. This patch prevents userspace tools(eg. setfattr, cp --preserve=xattr) from setting/modifying the 'security.evm' HMAC value directly. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* evm: checking if removexattr is not a NULLDmitry Kasatkin2013-02-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a67adb997419fb53540d4a4f79c6471c60bc69b6 upstream. The following lines of code produce a kernel oops. fd = socket(PF_FILE, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); fchmod(fd, 0666); [ 139.922364] BUG: unable to handle kernel NULL pointer dereference at (null) [ 139.924982] IP: [< (null)>] (null) [ 139.924982] *pde = 00000000 [ 139.924982] Oops: 0000 [#5] SMP [ 139.924982] Modules linked in: fuse dm_crypt dm_mod i2c_piix4 serio_raw evdev binfmt_misc button [ 139.924982] Pid: 3070, comm: acpid Tainted: G D 3.8.0-rc2-kds+ #465 Bochs Bochs [ 139.924982] EIP: 0060:[<00000000>] EFLAGS: 00010246 CPU: 0 [ 139.924982] EIP is at 0x0 [ 139.924982] EAX: cf5ef000 EBX: cf5ef000 ECX: c143d600 EDX: c15225f2 [ 139.924982] ESI: cf4d2a1c EDI: cf4d2a1c EBP: cc02df10 ESP: cc02dee4 [ 139.924982] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 139.924982] CR0: 80050033 CR2: 00000000 CR3: 0c059000 CR4: 000006d0 [ 139.924982] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 139.924982] DR6: ffff0ff0 DR7: 00000400 [ 139.924982] Process acpid (pid: 3070, ti=cc02c000 task=d7705340 task.ti=cc02c000) [ 139.924982] Stack: [ 139.924982] c1203c88 00000000 cc02def4 cf4d2a1c ae21eefa 471b60d5 1083c1ba c26a5940 [ 139.924982] e891fb5e 00000041 00000004 cc02df1c c1203964 00000000 cc02df4c c10e20c3 [ 139.924982] 00000002 00000000 00000000 22222222 c1ff2222 cf5ef000 00000000 d76efb08 [ 139.924982] Call Trace: [ 139.924982] [<c1203c88>] ? evm_update_evmxattr+0x5b/0x62 [ 139.924982] [<c1203964>] evm_inode_post_setattr+0x22/0x26 [ 139.924982] [<c10e20c3>] notify_change+0x25f/0x281 [ 139.924982] [<c10cbf56>] chmod_common+0x59/0x76 [ 139.924982] [<c10e27a1>] ? put_unused_fd+0x33/0x33 [ 139.924982] [<c10cca09>] sys_fchmod+0x39/0x5c [ 139.924982] [<c13f4f30>] syscall_call+0x7/0xb [ 139.924982] Code: Bad EIP value. This happens because sockets do not define the removexattr operation. Before removing the xattr, verify the removexattr function pointer is not NULL. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* ima: fix Kconfig dependenciesFabio Estevam2012-04-021-1/+1
| | | | | | | | | | | | | | | commit f4a0391dfa91155bd961673b31eb42d9d45c799d upstream. Fix the following build warning: warning: (IMA) selects TCG_TPM which has unmet direct dependencies (HAS_IOMEM && EXPERIMENTAL) Suggested-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ima: fix invalid memory referenceRoberto Sassu2012-01-251-5/+11
| | | | | | | | | | | commit 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da upstream. Don't free a valid measurement entry on TPM PCR extend failure. Signed-off-by: Roberto Sassu <roberto.sassu@polito.it> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* ima: free duplicate measurement memoryRoberto Sassu2012-01-252-2/+3
| | | | | | | | | | | | | | | | commit 45fae7493970d7c45626ccd96d4a74f5f1eea5a9 upstream. Info about new measurements are cached in the iint for performance. When the inode is flushed from cache, the associated iint is flushed as well. Subsequent access to the inode will cause the inode to be re-measured and will attempt to add a duplicate entry to the measurement list. This patch frees the duplicate measurement memory, fixing a memory leak. Signed-off-by: Roberto Sassu <roberto.sassu@polito.it> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* evm: prevent racing during tfm allocationDmitry Kasatkin2011-12-201-0/+9
| | | | | | | | | There is a small chance of racing during tfm allocation. This patch fixes it. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* evm: key must be set once during initializationDmitry Kasatkin2011-12-201-4/+6
| | | | | | | | | | | On multi-core systems, setting of the key before every caclculation, causes invalid HMAC calculation for other tfm users, because internal state (ipad, opad) can be invalid before set key call returns. It needs to be set only once during initialization. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* Merge branch 'for-linus' of git://github.com/richardweinberger/linuxLinus Torvalds2011-11-021-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://github.com/richardweinberger/linux: (90 commits) um: fix ubd cow size um: Fix kmalloc argument order in um/vdso/vma.c um: switch to use of drivers/Kconfig UserModeLinux-HOWTO.txt: fix a typo UserModeLinux-HOWTO.txt: remove ^H characters um: we need sys/user.h only on i386 um: merge delay_{32,64}.c um: distribute exports to where exported stuff is defined um: kill system-um.h um: generic ftrace.h will do... um: segment.h is x86-only and needed only there um: asm/pda.h is not needed anymore um: hw_irq.h can go generic as well um: switch to generic-y um: clean Kconfig up a bit um: a couple of missing dependencies... um: kill useless argument of free_chan() and free_one_chan() um: unify ptrace_user.h um: unify KSTK_... um: fix gcov build breakage ...
| * um: switch to use of drivers/KconfigAl Viro2011-11-021-1/+1
| | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
* | evm: clean verification statusDmitry Kasatkin2011-09-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | When allocating from slab, initialization is done the first time in init_once() and subsequently on free. Because evm_status was not re-initialized on free, evm_verify_hmac() skipped verifications. This patch re-initializes evm_status. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
* | evm: permit mode bits to be updatedMimi Zohar2011-09-141-17/+13
| | | | | | | | | | | | | | | | | | | | | | Before permitting 'security.evm' to be updated, 'security.evm' must exist and be valid. In the case that there are no existing EVM protected xattrs, it is safe for posix acls to update the mode bits. To differentiate between no 'security.evm' xattr and no xattrs used to calculate 'security.evm', this patch defines INTEGRITY_NOXATTR. Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
* | evm: posix acls modify i_modeMimi Zohar2011-09-143-5/+46
| | | | | | | | | | | | | | | | | | | | The posix xattr acls are 'system' prefixed, which normally would not affect security.evm. An interesting side affect of writing posix xattr acls is their modifying of the i_mode, which is included in security.evm. This patch updates security.evm when posix xattr acls are written. Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
* | evm: limit verifying current security.evm integrityMimi Zohar2011-09-141-34/+24
| | | | | | | | | | | | | | | | | | 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>
* | evm: remove TCG_TPM dependencyMimi Zohar2011-09-141-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All tristates selected by EVM(boolean) are forced to be builtin, except in the TCG_TPM(tristate) dependency case. Arnaud Lacombe summarizes the Kconfig bug as, "So it would seem direct dependency state influence the state of reverse dependencies.." For a detailed explanation, refer to Arnaud Lacombe's posting http://lkml.org/lkml/2011/8/23/498. With the "encrypted-keys: remove trusted-keys dependency" patch, EVM can now be built without a dependency on TCG_TPM. The trusted-keys dependency requires trusted-keys to either be builtin or not selected. This dependency will prevent the boolean/tristate mismatch from occuring. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>, Randy Dunlap <rdunlap@xenotimenet> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
* | ima: sparse fix: include linux/ima.h in ima_main.cJames Morris2011-09-091-0/+1
| | | | | | | | | | | | | | | | | | | | Fixes sparse warnings: security/integrity/ima/ima_main.c:105:6: warning: symbol 'ima_file_free' was not declared. Should it be static? security/integrity/ima/ima_main.c:167:5: warning: symbol 'ima_file_mmap' was not declared. Should it be static? security/integrity/ima/ima_main.c:192:5: warning: symbol 'ima_bprm_check' was not declared. Should it be static? security/integrity/ima/ima_main.c:211:5: warning: symbol 'ima_file_check' was not declared. Should it be static? Signed-off-by: James Morris <jmorris@namei.org>
* | ima: sparse fix: make ima_open_policy staticJames Morris2011-09-091-1/+1
| | | | | | | | | | | | | | Fixes sparse warning: security/integrity/ima/ima_fs.c:290:5: warning: symbol 'ima_open_policy' was not declared. Should it be static? Signed-off-by: James Morris <jmorris@namei.org>
* | integrity: sparse fix: move iint_initialized to integrity.hJames Morris2011-09-092-1/+3
| | | | | | | | | | | | Sparse fix: move iint_initialized to integrity.h Signed-off-by: James Morris <jmorris@namei.org>
* | evm: add Kconfig TCG_TPM dependencyMimi Zohar2011-08-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although the EVM encrypted-key should be encrypted/decrypted using a trusted-key, a user-defined key could be used instead. When using a user- defined key, a TCG_TPM dependency should not be required. Unfortunately, the encrypted-key code needs to be refactored a bit in order to remove this dependency. This patch adds the TCG_TPM dependency. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>, Randy Dunlap <rdunlap@xenotimenet> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* | evm: fix evm_inode_init_security return codeMimi Zohar2011-08-111-1/+1
| | | | | | | | | | | | | | | | evm_inode_init_security() should return 0, when EVM is not enabled. (Returning an error is a remnant of evm_inode_post_init_security.) Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* | EVM: ensure trusted and encypted key symbols are available to EVMJames Morris2011-08-091-1/+3
| | | | | | | | | | | | | | | | | | Select trusted and encrypted keys if EVM is selected, to ensure the requisite symbols are available. Otherwise, these can be selected as modules while EVM is static, leading to a kernel build failure. Signed-off-by: James Morris <jmorris@namei.org>
* | Merge branch 'next-evm' of ↵James Morris2011-08-0916-199/+1022
|\ \ | |/ |/| | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/zohar/ima-2.6 into next Conflicts: fs/attr.c Resolve conflict manually. Signed-off-by: James Morris <jmorris@namei.org>
| * evm: add evm_inode_setattr to prevent updating an invalid security.evmMimi Zohar2011-07-181-0/+15
| | | | | | | | | | | | | | Permit changing of security.evm only when valid, unless in fixmode. Reported-by: Roberto Sassu <roberto.sassu@polito.it> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
| * evm: permit only valid security.evm xattrs to be updatedMimi Zohar2011-07-181-14/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | In addition to requiring CAP_SYS_ADMIN permission to modify/delete security.evm, prohibit invalid security.evm xattrs from changing, unless in fixmode. This patch prevents inadvertent 'fixing' of security.evm to reflect offline modifications. Changelog v7: - rename boot paramater 'evm_mode' to 'evm' Reported-by: Roberto Sassu <roberto.sassu@polito.it> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
| * evm: replace hmac_status with evm_statusDmitry Kasatkin2011-07-183-9/+9
| | | | | | | | | | | | | | We will use digital signatures in addtion to hmac. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
| * evm: evm_verify_hmac must not return INTEGRITY_UNKNOWNDmitry Kasatkin2011-07-181-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If EVM is not supported or enabled, evm_verify_hmac() returns INTEGRITY_UNKNOWN, which ima_appraise_measurement() ignores and sets the appraisal status based solely on the security.ima verification. evm_verify_hmac() also returns INTEGRITY_UNKNOWN for other failures, such as temporary failures like -ENOMEM, resulting in possible attack vectors. This patch changes the default return code for temporary/unexpected failures, like -ENOMEM, from INTEGRITY_UNKNOWN to INTEGRITY_FAIL, making evm_verify_hmac() fail safe. As a result, failures need to be re-evaluated in order to catch both temporary errors, such as the -ENOMEM, as well as errors that have been resolved in fix mode. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
| * evm: additional parameter to pass integrity cache entry 'iint'Dmitry Kasatkin2011-07-181-10/+8
| | | | | | | | | | | | | | Additional iint parameter allows to skip lookup in the cache. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
| * evm: crypto hash replaced by shashDmitry Kasatkin2011-07-183-45/+57
| | | | | | | | | | | | | | | | | | | | | | | | Using shash is more efficient, because the algorithm is allocated only once. Only the descriptor to store the hash state needs to be allocated for every operation. Changelog v6: - check for crypto_shash_setkey failure Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
| * evm: add evm_inode_init_security to initialize new filesMimi Zohar2011-07-183-0/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | Initialize 'security.evm' for new files. Changelog v7: - renamed evm_inode_post_init_security to evm_inode_init_security - moved struct xattr definition to earlier patch - allocate xattr name Changelog v6: - Use 'struct evm_ima_xattr_data' Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
| * security: imbed evm calls in security hooksMimi Zohar2011-07-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Imbed the evm calls evm_inode_setxattr(), evm_inode_post_setxattr(), evm_inode_removexattr() in the security hooks. evm_inode_setxattr() protects security.evm xattr. evm_inode_post_setxattr() and evm_inode_removexattr() updates the hmac associated with an inode. (Assumes an LSM module protects the setting/removing of xattr.) Changelog: - Don't define evm_verifyxattr(), unless CONFIG_INTEGRITY is enabled. - xattr_name is a 'const', value is 'void *' Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
| * evm: add support for different security.evm data typesDmitry Kasatkin2011-07-183-9/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | EVM protects a file's security extended attributes(xattrs) against integrity attacks. The current patchset maintains an HMAC-sha1 value across the security xattrs, storing the value as the extended attribute 'security.evm'. We anticipate other methods for protecting the security extended attributes. This patch reserves the first byte of 'security.evm' as a place holder for the type of method. Changelog v6: - move evm_ima_xattr_type definition to security/integrity/integrity.h - defined a structure for the EVM xattr called evm_ima_xattr_data (based on Serge Hallyn's suggestion) - removed unnecessary memset Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
| * evm: re-releaseMimi Zohar2011-07-1810-1/+632
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | EVM protects a file's security extended attributes(xattrs) against integrity attacks. This patchset provides the framework and an initial method. The initial method maintains an HMAC-sha1 value across the security extended attributes, storing the HMAC value as the extended attribute 'security.evm'. Other methods of validating the integrity of a file's metadata will be posted separately (eg. EVM-digital-signatures). While this patchset does authenticate the security xattrs, and cryptographically binds them to the inode, coming extensions will bind other directory and inode metadata for more complete protection. To help simplify the review and upstreaming process, each extension will be posted separately (eg. IMA-appraisal, IMA-appraisal-directory). For a general overview of the proposed Linux integrity subsystem, refer to Dave Safford's whitepaper: http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf. EVM depends on the Kernel Key Retention System to provide it with a trusted/encrypted key for the HMAC-sha1 operation. The key is loaded onto the root's keyring using keyctl. Until EVM receives notification that the key has been successfully loaded onto the keyring (echo 1 > <securityfs>/evm), EVM can not create or validate the 'security.evm' xattr, but returns INTEGRITY_UNKNOWN. Loading the key and signaling EVM should be done as early as possible. Normally this is done in the initramfs, which has already been measured as part of the trusted boot. For more information on creating and loading existing trusted/encrypted keys, refer to Documentation/keys-trusted-encrypted.txt. A sample dracut patch, which loads the trusted/encrypted key and enables EVM, is available from http://linux-ima.sourceforge.net/#EVM. Based on the LSMs enabled, the set of EVM protected security xattrs is defined at compile. EVM adds the following three calls to the existing security hooks: evm_inode_setxattr(), evm_inode_post_setxattr(), and evm_inode_removexattr. To initialize and update the 'security.evm' extended attribute, EVM defines three calls: evm_inode_post_init(), evm_inode_post_setattr() and evm_inode_post_removexattr() hooks. To verify the integrity of a security xattr, EVM exports evm_verifyxattr(). Changelog v7: - Fixed URL in EVM ABI documentation Changelog v6: (based on Serge Hallyn's review) - fix URL in patch description - remove evm_hmac_size definition - use SHA1_DIGEST_SIZE (removed both MAX_DIGEST_SIZE and evm_hmac_size) - moved linux include before other includes - test for crypto_hash_setkey failure - fail earlier for invalid key - clear entire encrypted key, even on failure - check xattr name length before comparing xattr names Changelog: - locking based on i_mutex, remove evm_mutex - using trusted/encrypted keys for storing the EVM key used in the HMAC-sha1 operation. - replaced crypto hash with shash (Dmitry Kasatkin) - support for additional methods of verifying the security xattrs (Dmitry Kasatkin) - iint not allocated for all regular files, but only for those appraised - Use cap_sys_admin in lieu of cap_mac_admin - Use __vfs_setxattr_noperm(), without permission checks, from EVM Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
| * integrity: move ima inode integrity data managementMimi Zohar2011-07-1810-199/+242
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the inode integrity data(iint) management up to the integrity directory in order to share the iint among the different integrity models. Changelog: - don't define MAX_DIGEST_SIZE - rename several globally visible 'ima_' prefixed functions, structs, locks, etc to 'integrity_' - replace '20' with SHA1_DIGEST_SIZE - reflect location change in appropriate Kconfig and Makefiles - remove unnecessary initialization of iint_initialized to 0 - rebased on current ima_iint.c - define integrity_iint_store/lock as static There should be no other functional changes. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
* | ima: fmode_t misspelled as mode_t...Al Viro2011-07-261-1/+1
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ima: remove unnecessary call to ima_must_measureMimi Zohar2011-02-233-15/+7
| | | | | | | | | | | | | | | | | | The original ima_must_measure() function based its results on cached iint information, which required an iint be allocated for all files. Currently, an iint is allocated only for files in policy. As a result, for those files in policy, ima_must_measure() is now called twice: once to determine if the inode is in the measurement policy and, the second time, to determine if it needs to be measured/re-measured. The second call to ima_must_measure() unnecessarily checks to see if the file is in policy. As we already know the file is in policy, this patch removes the second unnecessary call to ima_must_measure(), removes the vestige iint parameter, and just checks the iint directly to determine if the inode has been measured or needs to be measured/re-measured. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Eric Paris <eparis@redhat.com>
* IMA: remove IMA imbalance checkingMimi Zohar2011-02-102-104/+4
| | | | | | | | Now that i_readcount is maintained by the VFS layer, remove the imbalance checking in IMA. Cleans up the IMA code nicely. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Eric Paris <eparis@redhat.com>
* IMA: maintain i_readcount in the VFS layerMimi Zohar2011-02-102-19/+8
| | | | | | | | | | | | | ima_counts_get() updated the readcount and invalidated the PCR, as necessary. Only update the i_readcount in the VFS layer. Move the PCR invalidation checks to ima_file_check(), where it belongs. Maintaining the i_readcount in the VFS layer, will allow other subsystems to use i_readcount. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Eric Paris <eparis@redhat.com>
* IMA: convert i_readcount to atomicMimi Zohar2011-02-102-8/+10
| | | | | | | Convert the inode's i_readcount from an unsigned int to atomic. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Eric Paris <eparis@redhat.com>
* ima: fix add LSM rule bugMimi Zohar2011-01-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If security_filter_rule_init() doesn't return a rule, then not everything is as fine as the return code implies. This bug only occurs when the LSM (eg. SELinux) is disabled at runtime. Adding an empty LSM rule causes ima_match_rules() to always succeed, ignoring any remaining rules. default IMA TCB policy: # PROC_SUPER_MAGIC dont_measure fsmagic=0x9fa0 # SYSFS_MAGIC dont_measure fsmagic=0x62656572 # DEBUGFS_MAGIC dont_measure fsmagic=0x64626720 # TMPFS_MAGIC dont_measure fsmagic=0x01021994 # SECURITYFS_MAGIC dont_measure fsmagic=0x73636673 < LSM specific rule > dont_measure obj_type=var_log_t measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC measure func=FILE_CHECK mask=MAY_READ uid=0 Thus without the patch, with the boot parameters 'tcb selinux=0', adding the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB measurement policy, would result in nothing being measured. The patch prevents the default TCB policy from being replaced. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Cc: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: David Safford <safford@watson.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: fix the ToMToU logicEric Paris2010-10-261-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current logic looks like this: rc = ima_must_measure(NULL, inode, MAY_READ, FILE_CHECK); if (rc < 0) goto out; if (mode & FMODE_WRITE) { if (inode->i_readcount) send_tomtou = true; goto out; } if (atomic_read(&inode->i_writecount) > 0) send_writers = true; Lets assume we have a policy which states that all files opened for read by root must be measured. Lets assume the file has permissions 777. Lets assume that root has the given file open for read. Lets assume that a non-root process opens the file write. The non-root process will get to ima_counts_get() and will check the ima_must_measure(). Since it is not supposed to measure it will goto out. We should check the i_readcount no matter what since we might be causing a ToMToU voilation! This is close to correct, but still not quite perfect. The situation could have been that root, which was interested in the mesurement opened and closed the file and another process which is not interested in the measurement is the one holding the i_readcount ATM. This is just overly strict on ToMToU violations, which is better than not strict enough... Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: explicit IMA i_flag to remove global lock on inode_deleteEric Paris2010-10-262-5/+12
| | | | | | | | | | | Currently for every removed inode IMA must take a global lock and search the IMA rbtree looking for an associated integrity structure. Instead we explicitly mark an inode when we add an integrity structure so we only have to take the global lock and do the removal if it exists. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: drop refcnt from ima_iint_cache since it isn't neededEric Paris2010-10-263-30/+19
| | | | | | | | | | | | | Since finding a struct ima_iint_cache requires a valid struct inode, and the struct ima_iint_cache is supposed to have the same lifetime as a struct inode (technically they die together but don't need to be created at the same time) we don't have to worry about the ima_iint_cache outliving or dieing before the inode. So the refcnt isn't useful. Just get rid of it and free the structure when the inode is freed. Signed-off-by: Eric Paris <eapris@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: only allocate iint when neededEric Paris2010-10-261-30/+64
| | | | | | | | | | | | | IMA always allocates an integrity structure to hold information about every inode, but only needed this structure to track the number of readers and writers currently accessing a given inode. Since that information was moved into struct inode instead of the integrity struct this patch stops allocating the integrity stucture until it is needed. Thus greatly reducing memory usage. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: move read counter into struct inodeEric Paris2010-10-264-34/+17
| | | | | | | | | | | | | | | | | | | | | IMA currently allocated an inode integrity structure for every inode in core. This stucture is about 120 bytes long. Most files however (especially on a system which doesn't make use of IMA) will never need any of this space. The problem is that if IMA is enabled we need to know information about the number of readers and the number of writers for every inode on the box. At the moment we collect that information in the per inode iint structure and waste the rest of the space. This patch moves those counters into the struct inode so we can eventually stop allocating an IMA integrity structure except when absolutely needed. This patch does the minimum needed to move the location of the data. Further cleanups, especially the location of counter updates, may still be possible. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: use i_writecount rather than a private counterEric Paris2010-10-263-17/+6
| | | | | | | | | | | | | | | | | | | | | | | | | IMA tracks the number of struct files which are holding a given inode readonly and the number which are holding the inode write or r/w. It needs this information so when a new reader or writer comes in it can tell if this new file will be able to invalidate results it already made about existing files. aka if a task is holding a struct file open RO, IMA measured the file and recorded those measurements and then a task opens the file RW IMA needs to note in the logs that the old measurement may not be correct. It's called a "Time of Measure Time of Use" (ToMToU) issue. The same is true is a RO file is opened to an inode which has an open writer. We cannot, with any validity, measure the file in question since it could be changing. This patch attempts to use the i_writecount field to track writers. The i_writecount field actually embeds more information in it's value than IMA needs but it should work for our purposes and allow us to shrink the struct inode even more. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: use inode->i_lock to protect read and write countersEric Paris2010-10-262-34/+24
| | | | | | | | | | Currently IMA used the iint->mutex to protect the i_readcount and i_writecount. This patch uses the inode->i_lock since we are going to start using in inode objects and that is the most appropriate lock. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: convert internal flags from long to charEric Paris2010-10-261-2/+2
| | | | | | | | | | The IMA flags is an unsigned long but there is only 1 flag defined. Lets save a little space and make it a char. This packs nicely next to the array of u8's. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: use unsigned int instead of long for countersEric Paris2010-10-263-9/+14
| | | | | | | | | | | Currently IMA uses 2 longs in struct inode. To save space (and as it seems impossible to overflow 32 bits) we switch these to unsigned int. The switch to unsigned does require slightly different checks for underflow, but it isn't complex. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: drop the inode opencount since it isn't needed for operationEric Paris2010-10-263-14/+3
| | | | | | | | | | | | The opencount was used to help debugging to make sure that everything which created a struct file also correctly made the IMA calls. Since we moved all of that into the VFS this isn't as necessary. We should be able to get the same amount of debugging out of just the reader and write count. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IMA: use rbtree instead of radix tree for inode information cacheEric Paris2010-10-262-36/+75
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The IMA code needs to store the number of tasks which have an open fd granting permission to write a file even when IMA is not in use. It needs this information in order to be enabled at a later point in time without losing it's integrity garantees. At the moment that means we store a little bit of data about every inode in a cache. We use a radix tree key'd on the inode's memory address. Dave Chinner pointed out that a radix tree is a terrible data structure for such a sparse key space. This patch switches to using an rbtree which should be more efficient. Bug report from Dave: "I just noticed that slabtop was reporting an awfully high usage of radix tree nodes: OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 4200331 2778082 66% 0.55K 144839 29 2317424K radix_tree_node 2321500 2060290 88% 1.00K 72581 32 2322592K xfs_inode 2235648 2069791 92% 0.12K 69864 32 279456K iint_cache That is, 2.7M radix tree nodes are allocated, and the cache itself is consuming 2.3GB of RAM. I know that the XFS inodei caches are indexed by radix tree node, but for 2 million cached inodes that would mean a density of 1 inode per radix tree node, which for a system with 16M inodes in the filsystems is an impossibly low density. The worst I've seen in a production system like kernel.org is about 20-25% density, which would mean about 150-200k radix tree nodes for that many inodes. So it's not the inode cache. So I looked up what the iint_cache was. It appears to used for storing per-inode IMA information, and uses a radix tree for indexing. It uses the *address* of the struct inode as the indexing key. That means the key space is extremely sparse - for XFS the struct inode addresses are approximately 1000 bytes apart, which means the closest the radix tree index keys get is ~1000. Which means that there is a single entry per radix tree leaf node, so the radix tree is using roughly 550 bytes for every 120byte structure being cached. For the above example, it's probably wasting close to 1GB of RAM...." Reported-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.1 at 2024-05-27 15:03:58 +0000