From fa34e4b39a0d27086a2e797b637d8a1b1df89784 Mon Sep 17 00:00:00 2001 From: Sona Sarmadi Date: Mon, 8 Feb 2016 14:29:42 +0100 Subject: kernel/fs-userns: CVE-2014-4014 Change inode_capable to capable_wrt_inode_uidgid Fixes privileges escalation in Linux kernel built with the user namespaces(CONFIG_USER_NS). References: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4014 http://www.openwall.com/lists/oss-security/2014/06/10/4 Upstream patch: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/ patch/?id= 2246a472bce19c0d373fb5488a0e612e3328ce0a Signed-off-by: Sona Sarmadi --- .../linux/files/fs-userns-CVE-2014-4014.patch | 211 +++++++++++++++++++++ recipes-kernel/linux/linux-qoriq_3.12.bb | 1 + 2 files changed, 212 insertions(+) create mode 100644 recipes-kernel/linux/files/fs-userns-CVE-2014-4014.patch diff --git a/recipes-kernel/linux/files/fs-userns-CVE-2014-4014.patch b/recipes-kernel/linux/files/fs-userns-CVE-2014-4014.patch new file mode 100644 index 0000000..d6e4132 --- /dev/null +++ b/recipes-kernel/linux/files/fs-userns-CVE-2014-4014.patch @@ -0,0 +1,211 @@ +From 2246a472bce19c0d373fb5488a0e612e3328ce0a Mon Sep 17 00:00:00 2001 +From: Andy Lutomirski +Date: Tue, 10 Jun 2014 12:45:42 -0700 +Subject: fs,userns: Change inode_capable to capable_wrt_inode_uidgid + +commit 23adbe12ef7d3d4195e80800ab36b37bee28cd03 upstream. + +The kernel has no concept of capabilities with respect to inodes; inodes +exist independently of namespaces. For example, inode_capable(inode, +CAP_LINUX_IMMUTABLE) would be nonsense. + +This patch changes inode_capable to check for uid and gid mappings and +renames it to capable_wrt_inode_uidgid, which should make it more +obvious what it does. + +Fixes CVE-2014-4014. + +Upstream-Status: Backport + +Cc: Theodore Ts'o +Cc: Serge Hallyn +Cc: "Eric W. Biederman" +Cc: Dave Chinner +Signed-off-by: Andy Lutomirski +Signed-off-by: Linus Torvalds +Signed-off-by: Jiri Slaby +Signed-off-by: Sona Sarmadi +--- + fs/attr.c | 8 ++++---- + fs/inode.c | 10 +++++++--- + fs/namei.c | 11 ++++++----- + fs/xfs/xfs_ioctl.c | 2 +- + include/linux/capability.h | 2 +- + kernel/capability.c | 20 ++++++++------------ + 6 files changed, 27 insertions(+), 26 deletions(-) + +diff --git a/fs/attr.c b/fs/attr.c +index 8dd5825..66fa625 100644 +--- a/fs/attr.c ++++ b/fs/attr.c +@@ -50,14 +50,14 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr) + if ((ia_valid & ATTR_UID) && + (!uid_eq(current_fsuid(), inode->i_uid) || + !uid_eq(attr->ia_uid, inode->i_uid)) && +- !inode_capable(inode, CAP_CHOWN)) ++ !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return -EPERM; + + /* Make sure caller can chgrp. */ + if ((ia_valid & ATTR_GID) && + (!uid_eq(current_fsuid(), inode->i_uid) || + (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) && +- !inode_capable(inode, CAP_CHOWN)) ++ !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return -EPERM; + + /* Make sure a caller can chmod. */ +@@ -67,7 +67,7 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr) + /* Also check the setgid bit! */ + if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : + inode->i_gid) && +- !inode_capable(inode, CAP_FSETID)) ++ !capable_wrt_inode_uidgid(inode, CAP_FSETID)) + attr->ia_mode &= ~S_ISGID; + } + +@@ -160,7 +160,7 @@ void setattr_copy(struct inode *inode, const struct iattr *attr) + umode_t mode = attr->ia_mode; + + if (!in_group_p(inode->i_gid) && +- !inode_capable(inode, CAP_FSETID)) ++ !capable_wrt_inode_uidgid(inode, CAP_FSETID)) + mode &= ~S_ISGID; + inode->i_mode = mode; + } +diff --git a/fs/inode.c b/fs/inode.c +index b33ba8e..1e6e846 100644 +--- a/fs/inode.c ++++ b/fs/inode.c +@@ -1808,14 +1808,18 @@ EXPORT_SYMBOL(inode_init_owner); + * inode_owner_or_capable - check current task permissions to inode + * @inode: inode being checked + * +- * Return true if current either has CAP_FOWNER to the inode, or +- * owns the file. ++ * Return true if current either has CAP_FOWNER in a namespace with the ++ * inode owner uid mapped, or owns the file. + */ + bool inode_owner_or_capable(const struct inode *inode) + { ++ struct user_namespace *ns; ++ + if (uid_eq(current_fsuid(), inode->i_uid)) + return true; +- if (inode_capable(inode, CAP_FOWNER)) ++ ++ ns = current_user_ns(); ++ if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) + return true; + return false; + } +diff --git a/fs/namei.c b/fs/namei.c +index 187cacf..338d08b 100644 +--- a/fs/namei.c ++++ b/fs/namei.c +@@ -321,10 +321,11 @@ int generic_permission(struct inode *inode, int mask) + + if (S_ISDIR(inode->i_mode)) { + /* DACs are overridable for directories */ +- if (inode_capable(inode, CAP_DAC_OVERRIDE)) ++ if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE)) + return 0; + if (!(mask & MAY_WRITE)) +- if (inode_capable(inode, CAP_DAC_READ_SEARCH)) ++ if (capable_wrt_inode_uidgid(inode, ++ CAP_DAC_READ_SEARCH)) + return 0; + return -EACCES; + } +@@ -334,7 +335,7 @@ int generic_permission(struct inode *inode, int mask) + * at least one exec bit set. + */ + if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO)) +- if (inode_capable(inode, CAP_DAC_OVERRIDE)) ++ if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE)) + return 0; + + /* +@@ -342,7 +343,7 @@ int generic_permission(struct inode *inode, int mask) + */ + mask &= MAY_READ | MAY_WRITE | MAY_EXEC; + if (mask == MAY_READ) +- if (inode_capable(inode, CAP_DAC_READ_SEARCH)) ++ if (capable_wrt_inode_uidgid(inode, CAP_DAC_READ_SEARCH)) + return 0; + + return -EACCES; +@@ -2404,7 +2405,7 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) + return 0; + if (uid_eq(dir->i_uid, fsuid)) + return 0; +- return !inode_capable(inode, CAP_FOWNER); ++ return !capable_wrt_inode_uidgid(inode, CAP_FOWNER); + } + + /* +diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c +index 8c8ef24..52b5375 100644 +--- a/fs/xfs/xfs_ioctl.c ++++ b/fs/xfs/xfs_ioctl.c +@@ -1133,7 +1133,7 @@ xfs_ioctl_setattr( + * cleared upon successful return from chown() + */ + if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) && +- !inode_capable(VFS_I(ip), CAP_FSETID)) ++ !capable_wrt_inode_uidgid(VFS_I(ip), CAP_FSETID)) + ip->i_d.di_mode &= ~(S_ISUID|S_ISGID); + + /* +diff --git a/include/linux/capability.h b/include/linux/capability.h +index a6ee1f9..84b13ad 100644 +--- a/include/linux/capability.h ++++ b/include/linux/capability.h +@@ -210,7 +210,7 @@ extern bool has_ns_capability_noaudit(struct task_struct *t, + struct user_namespace *ns, int cap); + extern bool capable(int cap); + extern bool ns_capable(struct user_namespace *ns, int cap); +-extern bool inode_capable(const struct inode *inode, int cap); ++extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); + extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); + + /* audit system wants to get cap info from files as well */ +diff --git a/kernel/capability.c b/kernel/capability.c +index 4e66bf9..788653b 100644 +--- a/kernel/capability.c ++++ b/kernel/capability.c +@@ -433,23 +433,19 @@ bool capable(int cap) + EXPORT_SYMBOL(capable); + + /** +- * inode_capable - Check superior capability over inode ++ * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped + * @inode: The inode in question + * @cap: The capability in question + * +- * Return true if the current task has the given superior capability +- * targeted at it's own user namespace and that the given inode is owned +- * by the current user namespace or a child namespace. +- * +- * Currently we check to see if an inode is owned by the current +- * user namespace by seeing if the inode's owner maps into the +- * current user namespace. +- * ++ * Return true if the current task has the given capability targeted at ++ * its own user namespace and that the given inode's uid and gid are ++ * mapped into the current user namespace. + */ +-bool inode_capable(const struct inode *inode, int cap) ++bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) + { + struct user_namespace *ns = current_user_ns(); + +- return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid); ++ return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && ++ kgid_has_mapping(ns, inode->i_gid); + } +-EXPORT_SYMBOL(inode_capable); ++EXPORT_SYMBOL(capable_wrt_inode_uidgid); +-- +cgit v0.11.2 + diff --git a/recipes-kernel/linux/linux-qoriq_3.12.bb b/recipes-kernel/linux/linux-qoriq_3.12.bb index 262a6c8..bcf2930 100644 --- a/recipes-kernel/linux/linux-qoriq_3.12.bb +++ b/recipes-kernel/linux/linux-qoriq_3.12.bb @@ -35,6 +35,7 @@ SRC_URI = "git://git.freescale.com/ppc/sdk/linux.git;nobranch=1 \ file://udp-CVE-2015-5364_CVE-2015-5366.patch \ file://net-CVE-2015-2041.patch \ file://media-CVE-2014-1739.patch \ + file://fs-userns-CVE-2014-4014.patch \ " SRCREV = "6619b8b55796cdf0cec04b66a71288edd3057229" -- cgit v1.2.3-54-g00ecf