From 385ce0ea4c078517fa51c261882c4e72fba53005 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Mon, 4 Dec 2017 15:08:03 +0100 Subject: x86/mm/pti: Add Kconfig Finally allow CONFIG_PAGE_TABLE_ISOLATION to be enabled. PARAVIRT generally requires that the kernel not manage its own page tables. It also means that the hypervisor and kernel must agree wholeheartedly about what format the page tables are in and what they contain. PAGE_TABLE_ISOLATION, unfortunately, changes the rules and they can not be used together. I've seen conflicting feedback from maintainers lately about whether they want the Kconfig magic to go first or last in a patch series. It's going last here because the partially-applied series leads to kernels that can not boot in a bunch of cases. I did a run through the entire series with CONFIG_PAGE_TABLE_ISOLATION=y to look for build errors, though. [ tglx: Removed SMP and !PARAVIRT dependencies as they not longer exist ] Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar --- security/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'security') diff --git a/security/Kconfig b/security/Kconfig index e8e449444e65..a623d13bf288 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -54,6 +54,16 @@ config SECURITY_NETWORK implement socket and networking access controls. If you are unsure how to answer this question, answer N. +config PAGE_TABLE_ISOLATION + bool "Remove the kernel mapping in user mode" + depends on X86_64 && !UML + help + This feature reduces the number of hardware side channels by + ensuring that the majority of kernel addresses are not mapped + into userspace. + + See Documentation/x86/pagetable-isolation.txt for more details. + config SECURITY_INFINIBAND bool "Infiniband Security Hooks" depends on SECURITY && INFINIBAND -- cgit v1.2.3 From dc32b5c3e6e2ef29cef76d9ce1b92d394446150e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 1 Jan 2018 09:28:31 -0600 Subject: capabilities: fix buffer overread on very short xattr If userspace attempted to set a "security.capability" xattr shorter than 4 bytes (e.g. 'setfattr -n security.capability -v x file'), then cap_convert_nscap() read past the end of the buffer containing the xattr value because it accessed the ->magic_etc field without verifying that the xattr value is long enough to contain that field. Fix it by validating the xattr value size first. This bug was found using syzkaller with KASAN. The KASAN report was as follows (cleaned up slightly): BUG: KASAN: slab-out-of-bounds in cap_convert_nscap+0x514/0x630 security/commoncap.c:498 Read of size 4 at addr ffff88002d8741c0 by task syz-executor1/2852 CPU: 0 PID: 2852 Comm: syz-executor1 Not tainted 4.15.0-rc6-00200-gcc0aac99d977 #253 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xe3/0x195 lib/dump_stack.c:53 print_address_description+0x73/0x260 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x235/0x350 mm/kasan/report.c:409 cap_convert_nscap+0x514/0x630 security/commoncap.c:498 setxattr+0x2bd/0x350 fs/xattr.c:446 path_setxattr+0x168/0x1b0 fs/xattr.c:472 SYSC_setxattr fs/xattr.c:487 [inline] SyS_setxattr+0x36/0x50 fs/xattr.c:483 entry_SYSCALL_64_fastpath+0x18/0x85 Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities") Cc: # v4.14+ Signed-off-by: Eric Biggers Reviewed-by: Serge Hallyn Signed-off-by: James Morris --- security/commoncap.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'security') diff --git a/security/commoncap.c b/security/commoncap.c index 4f8e09340956..48620c93d697 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -348,21 +348,18 @@ static __u32 sansflags(__u32 m) return m & ~VFS_CAP_FLAGS_EFFECTIVE; } -static bool is_v2header(size_t size, __le32 magic) +static bool is_v2header(size_t size, const struct vfs_cap_data *cap) { - __u32 m = le32_to_cpu(magic); if (size != XATTR_CAPS_SZ_2) return false; - return sansflags(m) == VFS_CAP_REVISION_2; + return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_2; } -static bool is_v3header(size_t size, __le32 magic) +static bool is_v3header(size_t size, const struct vfs_cap_data *cap) { - __u32 m = le32_to_cpu(magic); - if (size != XATTR_CAPS_SZ_3) return false; - return sansflags(m) == VFS_CAP_REVISION_3; + return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_3; } /* @@ -405,7 +402,7 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, fs_ns = inode->i_sb->s_user_ns; cap = (struct vfs_cap_data *) tmpbuf; - if (is_v2header((size_t) ret, cap->magic_etc)) { + if (is_v2header((size_t) ret, cap)) { /* If this is sizeof(vfs_cap_data) then we're ok with the * on-disk value, so return that. */ if (alloc) @@ -413,7 +410,7 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, else kfree(tmpbuf); return ret; - } else if (!is_v3header((size_t) ret, cap->magic_etc)) { + } else if (!is_v3header((size_t) ret, cap)) { kfree(tmpbuf); return -EINVAL; } @@ -470,9 +467,9 @@ static kuid_t rootid_from_xattr(const void *value, size_t size, return make_kuid(task_ns, rootid); } -static bool validheader(size_t size, __le32 magic) +static bool validheader(size_t size, const struct vfs_cap_data *cap) { - return is_v2header(size, magic) || is_v3header(size, magic); + return is_v2header(size, cap) || is_v3header(size, cap); } /* @@ -495,7 +492,7 @@ int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size) if (!*ivalue) return -EINVAL; - if (!validheader(size, cap->magic_etc)) + if (!validheader(size, cap)) return -EINVAL; if (!capable_wrt_inode_uidgid(inode, CAP_SETFCAP)) return -EPERM; -- cgit v1.2.3 From 87faa0d9b43b4755ff6963a22d1fd1bee1aa3b39 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 3 Jan 2018 15:18:44 +0100 Subject: x86/pti: Enable PTI by default This really want's to be enabled by default. Users who know what they are doing can disable it either in the config or on the kernel command line. Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- security/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'security') diff --git a/security/Kconfig b/security/Kconfig index a623d13bf288..3d4debd0257e 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -56,6 +56,7 @@ config SECURITY_NETWORK config PAGE_TABLE_ISOLATION bool "Remove the kernel mapping in user mode" + default y depends on X86_64 && !UML help This feature reduces the number of hardware side channels by -- cgit v1.2.3 From 5b9f57cf47b87f07210875d6a24776b4496b818d Mon Sep 17 00:00:00 2001 From: John Johansen Date: Thu, 7 Dec 2017 00:28:27 -0800 Subject: apparmor: fix regression in mount mediation when feature set is pinned MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the mount code was refactored for Labels it was not correctly updated to check whether policy supported mediation of the mount class. This causes a regression when the kernel feature set is reported as supporting mount and policy is pinned to a feature set that does not support mount mediation. BugLink: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=882697#41 Fixes: 2ea3ffb7782a ("apparmor: add mount mediation") Reported-by: Fabian Grünbichler Cc: Stable Signed-off-by: John Johansen --- security/apparmor/mount.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c index ed9b4d0f9f7e..8c558cbce930 100644 --- a/security/apparmor/mount.c +++ b/security/apparmor/mount.c @@ -329,6 +329,9 @@ static int match_mnt_path_str(struct aa_profile *profile, AA_BUG(!mntpath); AA_BUG(!buffer); + if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT)) + return 0; + error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer, &mntpnt, &info, profile->disconnected); if (error) @@ -380,6 +383,9 @@ static int match_mnt(struct aa_profile *profile, const struct path *path, AA_BUG(!profile); AA_BUG(devpath && !devbuffer); + if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT)) + return 0; + if (devpath) { error = aa_path_name(devpath, path_flags(profile, devpath), devbuffer, &devname, &info, @@ -558,6 +564,9 @@ static int profile_umount(struct aa_profile *profile, struct path *path, AA_BUG(!profile); AA_BUG(!path); + if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT)) + return 0; + error = aa_path_name(path, path_flags(profile, path), buffer, &name, &info, profile->disconnected); if (error) @@ -613,7 +622,8 @@ static struct aa_label *build_pivotroot(struct aa_profile *profile, AA_BUG(!new_path); AA_BUG(!old_path); - if (profile_unconfined(profile)) + if (profile_unconfined(profile) || + !PROFILE_MEDIATES(profile, AA_CLASS_MOUNT)) return aa_get_newest_label(&profile->label); error = aa_path_name(old_path, path_flags(profile, old_path), -- cgit v1.2.3