Don't fetch fcaps when umount2 is called to avoid a process hang while it waits for the missing resource to (possibly never) re-appear. Note the comment above user_path_mountpoint_at(): * A umount is a special case for path walking. We're not actually interested * in the inode in this situation, and ESTALE errors can be a problem. We * simply want track down the dentry and vfsmount attached at the mountpoint * and avoid revalidating the last component. This can happen on ceph, cifs, 9p, lustre, fuse (gluster) or NFS. Please see the github issue tracker https://github.com/linux-audit/audit-kernel/issues/100 Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> --- fs/namei.c | 2 +- fs/namespace.c | 2 ++ include/linux/audit.h | 15 ++++++++++----- include/linux/namei.h | 3 +++ kernel/audit.c | 10 +++++++++- kernel/audit.h | 2 +- kernel/auditsc.c | 6 +++--- 7 files changed, 29 insertions(+), 11 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 914178cdbe94..87d7710a2e1d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2720,7 +2720,7 @@ int user_path_at_empty(int dfd, const char __user *name, unsigned flags, if (unlikely(error == -ESTALE)) error = path_mountpoint(&nd, flags | LOOKUP_REVAL, path); if (likely(!error)) - audit_inode(name, path->dentry, 0); + audit_inode(name, path->dentry, flags & LOOKUP_NO_EVAL); restore_nameidata(); putname(name); return error; diff --git a/fs/namespace.c b/fs/namespace.c index a677b59efd74..e5de0e372df2 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1640,6 +1640,8 @@ int ksys_umount(char __user *name, int flags) if (!(flags & UMOUNT_NOFOLLOW)) lookup_flags |= LOOKUP_FOLLOW; + lookup_flags |= LOOKUP_NO_EVAL; + retval = user_path_mountpoint_at(AT_FDCWD, name, lookup_flags, &path); if (retval) goto out; diff --git a/include/linux/audit.h b/include/linux/audit.h index a625c29a2ea2..5d914b534536 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -25,6 +25,7 @@ #include <linux/sched.h> #include <linux/ptrace.h> +#include <linux/namei.h> /* LOOKUP_* */ #include <uapi/linux/audit.h> #define AUDIT_INO_UNSET ((unsigned long)-1) @@ -225,6 +226,7 @@ extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, #define AUDIT_INODE_PARENT 1 /* dentry represents the parent */ #define AUDIT_INODE_HIDDEN 2 /* audit record should be hidden */ +#define AUDIT_INODE_NOEVAL 4 /* audit record incomplete */ extern void __audit_inode(struct filename *name, const struct dentry *dentry, unsigned int flags); extern void __audit_file(const struct file *); @@ -285,12 +287,15 @@ static inline void audit_getname(struct filename *name) } static inline void audit_inode(struct filename *name, const struct dentry *dentry, - unsigned int parent) { + unsigned int flags) { if (unlikely(!audit_dummy_context())) { - unsigned int flags = 0; - if (parent) - flags |= AUDIT_INODE_PARENT; - __audit_inode(name, dentry, flags); + unsigned int aflags = 0; + + if (flags & LOOKUP_PARENT) + aflags |= AUDIT_INODE_PARENT; + if (flags & LOOKUP_NO_EVAL) + aflags |= AUDIT_INODE_NOEVAL; + __audit_inode(name, dentry, aflags); } } static inline void audit_file(struct file *file) diff --git a/include/linux/namei.h b/include/linux/namei.h index a78606e8e3df..9138b4471dbf 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -24,6 +24,8 @@ * - internal "there are more path components" flag * - dentry cache is untrusted; force a real lookup * - suppress terminal automount + * - skip revalidation + * - don't fetch xattrs on audit_inode */ #define LOOKUP_FOLLOW 0x0001 #define LOOKUP_DIRECTORY 0x0002 @@ -33,6 +35,7 @@ #define LOOKUP_REVAL 0x0020 #define LOOKUP_RCU 0x0040 #define LOOKUP_NO_REVAL 0x0080 +#define LOOKUP_NO_EVAL 0x0100 /* * Intent data diff --git a/kernel/audit.c b/kernel/audit.c index ca55ccb46b76..45d5131943eb 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2081,6 +2081,10 @@ void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) { + if (name->fcap_ver == -1) { + audit_log_format(ab, " cap_fe=? cap_fver=? cap_fp=? cap_fi=?"); + return; + } audit_log_cap(ab, "cap_fp", &name->fcap.permitted); audit_log_cap(ab, "cap_fi", &name->fcap.inheritable); audit_log_format(ab, " cap_fe=%d cap_fver=%x", @@ -2111,7 +2115,7 @@ static inline int audit_copy_fcaps(struct audit_names *name, /* Copy inode data into an audit_names. */ void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, - struct inode *inode) + struct inode *inode, unsigned int flags) { name->ino = inode->i_ino; name->dev = inode->i_sb->s_dev; @@ -2120,6 +2124,10 @@ void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, name->gid = inode->i_gid; name->rdev = inode->i_rdev; security_inode_getsecid(inode, &name->osid); + if (flags & AUDIT_INODE_NOEVAL) { + name->fcap_ver = -1; + return; + } audit_copy_fcaps(name, dentry); } diff --git a/kernel/audit.h b/kernel/audit.h index 6ffb70575082..25ab276be8e5 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -214,7 +214,7 @@ struct audit_context { extern void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, - struct inode *inode); + struct inode *inode, unsigned int flags); extern void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap); extern void audit_log_name(struct audit_context *context, diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3d05d5fc6240..9a1257afc4d4 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1853,7 +1853,7 @@ void __audit_inode(struct filename *name, const struct dentry *dentry, n->type = AUDIT_TYPE_NORMAL; } handle_path(dentry); - audit_copy_inode(n, dentry, inode); + audit_copy_inode(n, dentry, inode, flags & AUDIT_INODE_NOEVAL); } void __audit_file(const struct file *file) @@ -1952,7 +1952,7 @@ void __audit_inode_child(struct inode *parent, n = audit_alloc_name(context, AUDIT_TYPE_PARENT); if (!n) return; - audit_copy_inode(n, NULL, parent); + audit_copy_inode(n, NULL, parent, 0); } if (!found_child) { @@ -1971,7 +1971,7 @@ void __audit_inode_child(struct inode *parent, } if (inode) - audit_copy_inode(found_child, dentry, inode); + audit_copy_inode(found_child, dentry, inode, 0); else found_child->ino = AUDIT_INO_UNSET; } -- 1.8.3.1
