On Wed, Jan 23, 2019 at 01:35:00PM -0500, Richard Guy Briggs wrote: > 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) { I don't know if this has been reported or if I am missing something but on next-20190201, this line causes an error with arm allyesconfig (as CONFIG_AUDITSYCALL doesn't get selected): $ make -j$(nproc) ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- allyesconfig kernel/audit.o HOSTCC scripts/basic/fixdep HOSTCC scripts/kconfig/confdata.o HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/expr.o YACC scripts/kconfig/parser.tab.h YACC scripts/kconfig/parser.tab.c LEX scripts/kconfig/lexer.lex.c HOSTCC scripts/kconfig/symbol.o HOSTCC scripts/kconfig/preprocess.o HOSTCC scripts/kconfig/parser.tab.o HOSTCC scripts/kconfig/lexer.lex.o HOSTLD scripts/kconfig/conf scripts/kconfig/conf --allyesconfig Kconfig # # configuration written to .config # SYSHDR arch/arm/include/generated/uapi/asm/unistd-common.h SYSHDR arch/arm/include/generated/uapi/asm/unistd-oabi.h SYSHDR arch/arm/include/generated/uapi/asm/unistd-eabi.h WRAP arch/arm/include/generated/uapi/asm/bitsperlong.h WRAP arch/arm/include/generated/uapi/asm/ipcbuf.h WRAP arch/arm/include/generated/uapi/asm/bpf_perf_event.h WRAP arch/arm/include/generated/uapi/asm/errno.h WRAP arch/arm/include/generated/uapi/asm/msgbuf.h WRAP arch/arm/include/generated/uapi/asm/ioctl.h WRAP arch/arm/include/generated/uapi/asm/sembuf.h WRAP arch/arm/include/generated/uapi/asm/shmbuf.h WRAP arch/arm/include/generated/uapi/asm/param.h WRAP arch/arm/include/generated/uapi/asm/poll.h WRAP arch/arm/include/generated/uapi/asm/resource.h WRAP arch/arm/include/generated/uapi/asm/siginfo.h WRAP arch/arm/include/generated/uapi/asm/termbits.h WRAP arch/arm/include/generated/uapi/asm/socket.h WRAP arch/arm/include/generated/uapi/asm/sockios.h WRAP arch/arm/include/generated/uapi/asm/termios.h UPD include/generated/uapi/linux/version.h WRAP arch/arm/include/generated/asm/current.h WRAP arch/arm/include/generated/asm/compat.h WRAP arch/arm/include/generated/asm/emergency-restart.h WRAP arch/arm/include/generated/asm/early_ioremap.h WRAP arch/arm/include/generated/asm/exec.h WRAP arch/arm/include/generated/asm/irq_regs.h WRAP arch/arm/include/generated/asm/extable.h WRAP arch/arm/include/generated/asm/kdebug.h WRAP arch/arm/include/generated/asm/local64.h WRAP arch/arm/include/generated/asm/msi.h WRAP arch/arm/include/generated/asm/parport.h WRAP arch/arm/include/generated/asm/local.h WRAP arch/arm/include/generated/asm/segment.h WRAP arch/arm/include/generated/asm/mm-arch-hooks.h WRAP arch/arm/include/generated/asm/preempt.h WRAP arch/arm/include/generated/asm/simd.h WRAP arch/arm/include/generated/asm/rwsem.h WRAP arch/arm/include/generated/asm/seccomp.h WRAP arch/arm/include/generated/asm/serial.h WRAP arch/arm/include/generated/asm/timex.h WRAP arch/arm/include/generated/asm/trace_clock.h WRAP arch/arm/include/generated/asm/sizes.h HOSTCC scripts/dtc/dtc.o HOSTCC scripts/dtc/fstree.o HOSTCC scripts/dtc/flattree.o HOSTCC scripts/dtc/data.o HOSTCC scripts/dtc/livetree.o HOSTCC scripts/dtc/treesource.o HOSTCC scripts/dtc/srcpos.o HOSTCC scripts/dtc/util.o HOSTCC scripts/dtc/checks.o LEX scripts/dtc/dtc-lexer.lex.c YACC scripts/dtc/dtc-parser.tab.h YACC scripts/dtc/dtc-parser.tab.c HOSTCC scripts/dtc/yamltree.o UPD include/config/kernel.release UPD include/generated/utsrelease.h HOSTCC scripts/dtc/dtc-parser.tab.o HOSTCC scripts/dtc/dtc-lexer.lex.o HOSTLD scripts/dtc/dtc HOSTCC scripts/bin2c HOSTCC scripts/kallsyms HOSTCC scripts/pnmtologo HOSTCC scripts/conmakehash HOSTCC scripts/recordmcount HOSTCC scripts/sortextable HOSTCC scripts/sign-file HOSTCC scripts/asn1_compiler HOSTCC scripts/extract-cert HOSTCC scripts/insert-sys-cert HOSTCC scripts/genksyms/genksyms.o YACC scripts/genksyms/parse.tab.c YACC scripts/genksyms/parse.tab.h LEX scripts/genksyms/lex.lex.c HOSTCXX -fPIC scripts/gcc-plugins/latent_entropy_plugin.o HOSTCXX -fPIC scripts/gcc-plugins/structleak_plugin.o GENSEED scripts/gcc-plugins/randomize_layout_seed.h HOSTCC scripts/selinux/genheaders/genheaders HOSTCXX -fPIC scripts/gcc-plugins/arm_ssp_per_task_plugin.o HOSTCC scripts/selinux/mdp/mdp HOSTCC scripts/genksyms/parse.tab.o HOSTCC scripts/genksyms/lex.lex.o HOSTLD scripts/genksyms/genksyms HOSTCXX -fPIC scripts/gcc-plugins/randomize_layout_plugin.o HOSTLLD -shared scripts/gcc-plugins/structleak_plugin.so HOSTLLD -shared scripts/gcc-plugins/latent_entropy_plugin.so HOSTLLD -shared scripts/gcc-plugins/arm_ssp_per_task_plugin.so HOSTLLD -shared scripts/gcc-plugins/randomize_layout_plugin.so GEN arch/arm/include/generated/asm/mach-types.h SYSNR arch/arm/include/generated/asm/unistd-nr.h SYSTBL arch/arm/include/generated/calls-oabi.S SYSTBL arch/arm/include/generated/calls-eabi.S HOSTCC scripts/mod/mk_elfconfig CC scripts/mod/devicetable-offsets.s CC scripts/mod/empty.o UPD scripts/mod/devicetable-offsets.h MKELF scripts/mod/elfconfig.h HOSTCC scripts/mod/modpost.o HOSTCC scripts/mod/sumversion.o HOSTCC scripts/mod/file2alias.o HOSTLD scripts/mod/modpost CC kernel/bounds.s CALL scripts/atomic/check-atomics.sh UPD include/generated/timeconst.h UPD include/generated/bounds.h CC arch/arm/kernel/asm-offsets.s UPD include/generated/asm-offsets.h CALL scripts/checksyscalls.sh <stdin>:1469:2: warning: #warning syscall pidfd_send_signal not implemented [-Wcpp] CC kernel/audit.o kernel/audit.c: In function 'audit_copy_inode': kernel/audit.c:2130:14: error: 'AUDIT_INODE_NOEVAL' undeclared (first use in this function); did you mean 'AUDIT_TYPE_NORMAL'? if (flags & AUDIT_INODE_NOEVAL) { ^~~~~~~~~~~~~~~~~~ AUDIT_TYPE_NORMAL kernel/audit.c:2130:14: note: each undeclared identifier is reported only once for each function it appears in make[2]: *** [scripts/Makefile.build:277: kernel/audit.o] Error 1 make[1]: *** [Makefile:1699: kernel/audit.o] Error 2 make: *** [Makefile:296: __build_one_by_one] Error 2 > + 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 >
