kernel/security, branch linux-3.2.y

SELinux: security_load_policy: Silence frame-larger-than warning

2018-03-19T18:58:23Z

commit b5495b4217d3fa64deac479db83dbede149af7d8 upstream. Dynamically allocate a couple of the larger stack variables in order to reduce the stack footprint below 1024. gcc-4.8 security/selinux/ss/services.c: In function 'security_load_policy': security/selinux/ss/services.c:1964:1: warning: the frame size of 1104 bytes is larger than 1024 bytes [-Wframe-larger-than=] } Also silence a couple of checkpatch warnings at the same time. WARNING: sizeof policydb should be sizeof(policydb) + memcpy(oldpolicydb, &policydb, sizeof policydb); WARNING: sizeof policydb should be sizeof(policydb) + memcpy(&policydb, newpolicydb, sizeof policydb); Cc: Stephen Smalley Cc: James Morris Cc: Eric Paris Signed-off-by: Tim Gardner Signed-off-by: Paul Moore Signed-off-by: Ben Hutchings

KPTI: Rename to PAGE_TABLE_ISOLATION

2018-01-07T01:46:54Z

This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2] Signed-off-by: Ben Hutchings

x86/kaiser: Reenable PARAVIRT

2018-01-07T01:46:53Z

Now that the required bits have been addressed, reenable PARAVIRT. Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

KAISER: Kernel Address Isolation

2018-01-07T01:46:49Z

This patch introduces our implementation of KAISER (Kernel Address Isolation to have Side-channels Efficiently Removed), a kernel isolation technique to close hardware side channels on kernel address information. More information about the original patch can be found at: https://github.com/IAIK/KAISER http://marc.info/?l=linux-kernel&m=149390087310405&w=2 Daniel Gruss Richard Fellner Michael Schwarz That original was then developed further by Dave Hansen Hugh Dickins then others after this snapshot. This combined patch for 3.2.96 was derived from hughd's patches below for 3.18.72, in 2017-12-04's kaiser-3.18.72.tar; except for the last, which was sent in 2017-12-09's nokaiser-3.18.72.tar. They have been combined in order to minimize the effort of rebasing: most of the patches in the 3.18.72 series were small fixes and cleanups and enhancements to three large patches. About the only new work in this backport is a simple reimplementation of kaiser_remove_mapping(): since mm/pageattr.c changed a lot between 3.2 and 3.18, and the mods there for Kaiser never seemed necessary. KAISER: Kernel Address Isolation kaiser: merged update kaiser: do not set _PAGE_NX on pgd_none kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE kaiser: fix build and FIXME in alloc_ldt_struct() kaiser: KAISER depends on SMP kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER kaiser: fix perf crashes kaiser: ENOMEM if kaiser_pagetable_walk() NULL kaiser: tidied up asm/kaiser.h somewhat kaiser: tidied up kaiser_add/remove_mapping slightly kaiser: kaiser_remove_mapping() move along the pgd kaiser: align addition to x86/mm/Makefile kaiser: cleanups while trying for gold link kaiser: name that 0x1000 KAISER_SHADOW_PGD_OFFSET kaiser: delete KAISER_REAL_SWITCH option kaiser: vmstat show NR_KAISERTABLE as nr_overhead kaiser: enhanced by kernel and user PCIDs kaiser: load_new_mm_cr3() let SWITCH_USER_CR3 flush user kaiser: PCID 0 for kernel and 128 for user kaiser: x86_cr3_pcid_noflush and x86_cr3_pcid_user kaiser: paranoid_entry pass cr3 need to paranoid_exit kaiser: _pgd_alloc() without __GFP_REPEAT to avoid stalls kaiser: fix unlikely error in alloc_ldt_struct() kaiser: drop is_atomic arg to kaiser_pagetable_walk() Signed-off-by: Hugh Dickins [bwh: - Fixed the #undef in arch/x86/boot/compressed/misc.h - Add missing #include in arch/x86/mm/kaiser.c] Signed-off-by: Ben Hutchings

KEYS: add missing permission check for request_key() destination

2018-01-01T20:51:05Z

commit 4dca6ea1d9432052afb06baf2e3ae78188a4410b upstream. When the request_key() syscall is not passed a destination keyring, it links the requested key (if constructed) into the "default" request-key keyring. This should require Write permission to the keyring. However, there is actually no permission check. This can be abused to add keys to any keyring to which only Search permission is granted. This is because Search permission allows joining the keyring. keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_SESSION_KEYRING) then will set the default request-key keyring to the session keyring. Then, request_key() can be used to add keys to the keyring. Both negatively and positively instantiated keys can be added using this method. Adding negative keys is trivial. Adding a positive key is a bit trickier. It requires that either /sbin/request-key positively instantiates the key, or that another thread adds the key to the process keyring at just the right time, such that request_key() misses it initially but then finds it in construct_alloc_key(). Fix this bug by checking for Write permission to the keyring in construct_get_dest_keyring() when the default keyring is being used. We don't do the permission check for non-default keyrings because that was already done by the earlier call to lookup_user_key(). Also, request_key_and_link() is currently passed a 'struct key *' rather than a key_ref_t, so the "possessed" bit is unavailable. We also don't do the permission check for the "requestor keyring", to continue to support the use case described by commit 8bbf4976b59f ("KEYS: Alter use of key instantiation link-to-keyring argument") where /sbin/request-key recursively calls request_key() to add keys to the original requestor's destination keyring. (I don't know of any users who actually do that, though...) Fixes: 3e30148c3d52 ("[PATCH] Keys: Make request-key create an authorisation key") Signed-off-by: Eric Biggers Signed-off-by: David Howells [bwh: Backported to 3.2: - s/KEY_NEED_WRITE/KEY_WRITE/ - Adjust context] Signed-off-by: Ben Hutchings

security: Fix mode test in selinux_ptrace_access_check()

2018-01-01T20:51:04Z

Commit 1c8d42255f4c "ptrace: use fsuid, fsgid, effective creds for fs access checks" added flags to the ptrace mode which need to be ignored here. This change was made upstream in 3.3 as part of commit 69f594a38967 "ptrace: do not audit capability check when outputing /proc/pid/stat", but that's probably not suitable for stable due to its dependencies. Signed-off-by: Ben Hutchings

KEYS: trusted: fix writing past end of buffer in trusted_read()

2018-01-01T20:51:01Z

commit a3c812f7cfd80cf51e8f5b7034f7418f6beb56c1 upstream. When calling keyctl_read() on a key of type "trusted", if the user-supplied buffer was too small, the kernel ignored the buffer length and just wrote past the end of the buffer, potentially corrupting userspace memory. Fix it by instead returning the size required, as per the documentation for keyctl_read(). We also don't even fill the buffer at all in this case, as this is slightly easier to implement than doing a short read, and either behavior appears to be permitted. It also makes it match the behavior of the "encrypted" key type. Fixes: d00a1c72f7f4 ("keys: add new trusted key-type") Reported-by: Ben Hutchings Signed-off-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: Mimi Zohar Reviewed-by: James Morris Signed-off-by: James Morris Signed-off-by: Ben Hutchings

KEYS: trusted: sanitize all key material

2018-01-01T20:51:01Z

commit ee618b4619b72527aaed765f0f0b74072b281159 upstream. As the previous patch did for encrypted-keys, zero sensitive any potentially sensitive data related to the "trusted" key type before it is freed. Notably, we were not zeroing the tpm_buf structures in which the actual key is stored for TPM seal and unseal, nor were we zeroing the trusted_key_payload in certain error paths. Cc: Mimi Zohar Cc: David Safford Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris [bwh: Backported to 3.2: - Also use kzfree() in my_get_random() - Drop one unapplicable change - Adjust context] Signed-off-by: Ben Hutchings

KEYS: encrypted: fix dereference of NULL user_key_payload

2018-01-01T20:50:57Z

commit 13923d0865ca96312197962522e88bc0aedccd74 upstream. A key of type "encrypted" references a "master key" which is used to encrypt and decrypt the encrypted key's payload. However, when we accessed the master key's payload, we failed to handle the case where the master key has been revoked, which sets the payload pointer to NULL. Note that request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. This was an issue for master keys of type "user" only. Master keys can also be of type "trusted", but those cannot be revoked. Fixes: 7e70cb497850 ("keys: add new key-type encrypted") Reviewed-by: James Morris Cc: Mimi Zohar Cc: David Safford Signed-off-by: Eric Biggers Signed-off-by: David Howells [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

lsm: fix smack_inode_removexattr and xattr_getsecurity memleak

2018-01-01T20:50:56Z

commit 57e7ba04d422c3d41c8426380303ec9b7533ded9 upstream. security_inode_getsecurity() provides the text string value of a security attribute. It does not provide a "secctx". The code in xattr_getsecurity() that calls security_inode_getsecurity() and then calls security_release_secctx() happened to work because SElinux and Smack treat the attribute and the secctx the same way. It fails for cap_inode_getsecurity(), because that module has no secctx that ever needs releasing. It turns out that Smack is the one that's doing things wrong by not allocating memory when instructed to do so by the "alloc" parameter. The fix is simple enough. Change the security_release_secctx() to kfree() because it isn't a secctx being returned by security_inode_getsecurity(). Change Smack to allocate the string when told to do so. Note: this also fixes memory leaks for LSMs which implement inode_getsecurity but not release_secctx, such as capabilities. Signed-off-by: Casey Schaufler Reported-by: Konstantin Khlebnikov Signed-off-by: James Morris [bwh: Backported to 3.2: - s/isp->smk_known/isp/ - Adjust context] Signed-off-by: Ben Hutchings