1. 23 9月, 2009 1 次提交
    • J
      getrusage: fill ru_maxrss value · 1f10206c
      Jiri Pirko 提交于
      Make ->ru_maxrss value in struct rusage filled accordingly to rss hiwater
      mark.  This struct is filled as a parameter to getrusage syscall.
      ->ru_maxrss value is set to KBs which is the way it is done in BSD
      systems.  /usr/bin/time (gnu time) application converts ->ru_maxrss to KBs
      which seems to be incorrect behavior.  Maintainer of this util was
      notified by me with the patch which corrects it and cc'ed.
      
      To make this happen we extend struct signal_struct by two fields.  The
      first one is ->maxrss which we use to store rss hiwater of the task.  The
      second one is ->cmaxrss which we use to store highest rss hiwater of all
      task childs.  These values are used in k_getrusage() to actually fill
      ->ru_maxrss.  k_getrusage() uses current rss hiwater value directly if mm
      struct exists.
      
      Note:
      exec() clear mm->hiwater_rss, but doesn't clear sig->maxrss.
      it is intetionally behavior. *BSD getrusage have exec() inheriting.
      
      test programs
      ========================================================
      
      getrusage.c
      ===========
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <sys/types.h>
       #include <sys/time.h>
       #include <sys/resource.h>
       #include <sys/types.h>
       #include <sys/wait.h>
       #include <unistd.h>
       #include <signal.h>
       #include <sys/mman.h>
      
       #include "common.h"
      
       #define err(str) perror(str), exit(1)
      
      int main(int argc, char** argv)
      {
      	int status;
      
      	printf("allocate 100MB\n");
      	consume(100);
      
      	printf("testcase1: fork inherit? \n");
      	printf("  expect: initial.self ~= child.self\n");
      	show_rusage("initial");
      	if (__fork()) {
      		wait(&status);
      	} else {
      		show_rusage("fork child");
      		_exit(0);
      	}
      	printf("\n");
      
      	printf("testcase2: fork inherit? (cont.) \n");
      	printf("  expect: initial.children ~= 100MB, but child.children = 0\n");
      	show_rusage("initial");
      	if (__fork()) {
      		wait(&status);
      	} else {
      		show_rusage("child");
      		_exit(0);
      	}
      	printf("\n");
      
      	printf("testcase3: fork + malloc \n");
      	printf("  expect: child.self ~= initial.self + 50MB\n");
      	show_rusage("initial");
      	if (__fork()) {
      		wait(&status);
      	} else {
      		printf("allocate +50MB\n");
      		consume(50);
      		show_rusage("fork child");
      		_exit(0);
      	}
      	printf("\n");
      
      	printf("testcase4: grandchild maxrss\n");
      	printf("  expect: post_wait.children ~= 300MB\n");
      	show_rusage("initial");
      	if (__fork()) {
      		wait(&status);
      		show_rusage("post_wait");
      	} else {
      		system("./child -n 0 -g 300");
      		_exit(0);
      	}
      	printf("\n");
      
      	printf("testcase5: zombie\n");
      	printf("  expect: pre_wait ~= initial, IOW the zombie process is not accounted.\n");
      	printf("          post_wait ~= 400MB, IOW wait() collect child's max_rss. \n");
      	show_rusage("initial");
      	if (__fork()) {
      		sleep(1); /* children become zombie */
      		show_rusage("pre_wait");
      		wait(&status);
      		show_rusage("post_wait");
      	} else {
      		system("./child -n 400");
      		_exit(0);
      	}
      	printf("\n");
      
      	printf("testcase6: SIG_IGN\n");
      	printf("  expect: initial ~= after_zombie (child's 500MB alloc should be ignored).\n");
      	show_rusage("initial");
      	signal(SIGCHLD, SIG_IGN);
      	if (__fork()) {
      		sleep(1); /* children become zombie */
      		show_rusage("after_zombie");
      	} else {
      		system("./child -n 500");
      		_exit(0);
      	}
      	printf("\n");
      	signal(SIGCHLD, SIG_DFL);
      
      	printf("testcase7: exec (without fork) \n");
      	printf("  expect: initial ~= exec \n");
      	show_rusage("initial");
      	execl("./child", "child", "-v", NULL);
      
      	return 0;
      }
      
      child.c
      =======
       #include <sys/types.h>
       #include <unistd.h>
       #include <sys/types.h>
       #include <sys/wait.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <sys/types.h>
       #include <sys/time.h>
       #include <sys/resource.h>
      
       #include "common.h"
      
      int main(int argc, char** argv)
      {
      	int status;
      	int c;
      	long consume_size = 0;
      	long grandchild_consume_size = 0;
      	int show = 0;
      
      	while ((c = getopt(argc, argv, "n:g:v")) != -1) {
      		switch (c) {
      		case 'n':
      			consume_size = atol(optarg);
      			break;
      		case 'v':
      			show = 1;
      			break;
      		case 'g':
      
      			grandchild_consume_size = atol(optarg);
      			break;
      		default:
      			break;
      		}
      	}
      
      	if (show)
      		show_rusage("exec");
      
      	if (consume_size) {
      		printf("child alloc %ldMB\n", consume_size);
      		consume(consume_size);
      	}
      
      	if (grandchild_consume_size) {
      		if (fork()) {
      			wait(&status);
      		} else {
      			printf("grandchild alloc %ldMB\n", grandchild_consume_size);
      			consume(grandchild_consume_size);
      
      			exit(0);
      		}
      	}
      
      	return 0;
      }
      
      common.c
      ========
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <sys/types.h>
       #include <sys/time.h>
       #include <sys/resource.h>
       #include <sys/types.h>
       #include <sys/wait.h>
       #include <unistd.h>
       #include <signal.h>
       #include <sys/mman.h>
      
       #include "common.h"
       #define err(str) perror(str), exit(1)
      
      void show_rusage(char *prefix)
      {
          	int err, err2;
          	struct rusage rusage_self;
          	struct rusage rusage_children;
      
          	printf("%s: ", prefix);
          	err = getrusage(RUSAGE_SELF, &rusage_self);
          	if (!err)
          		printf("self %ld ", rusage_self.ru_maxrss);
          	err2 = getrusage(RUSAGE_CHILDREN, &rusage_children);
          	if (!err2)
          		printf("children %ld ", rusage_children.ru_maxrss);
      
          	printf("\n");
      }
      
      /* Some buggy OS need this worthless CPU waste. */
      void make_pagefault(void)
      {
      	void *addr;
      	int size = getpagesize();
      	int i;
      
      	for (i=0; i<1000; i++) {
      		addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
      		if (addr == MAP_FAILED)
      			err("make_pagefault");
      		memset(addr, 0, size);
      		munmap(addr, size);
      	}
      }
      
      void consume(int mega)
      {
          	size_t sz = mega * 1024 * 1024;
          	void *ptr;
      
          	ptr = malloc(sz);
          	memset(ptr, 0, sz);
      	make_pagefault();
      }
      
      pid_t __fork(void)
      {
      	pid_t pid;
      
      	pid = fork();
      	make_pagefault();
      
      	return pid;
      }
      
      common.h
      ========
      void show_rusage(char *prefix);
      void make_pagefault(void);
      void consume(int mega);
      pid_t __fork(void);
      
      FreeBSD result (expected result)
      ========================================================
      allocate 100MB
      testcase1: fork inherit?
        expect: initial.self ~= child.self
      initial: self 103492 children 0
      fork child: self 103540 children 0
      
      testcase2: fork inherit? (cont.)
        expect: initial.children ~= 100MB, but child.children = 0
      initial: self 103540 children 103540
      child: self 103564 children 0
      
      testcase3: fork + malloc
        expect: child.self ~= initial.self + 50MB
      initial: self 103564 children 103564
      allocate +50MB
      fork child: self 154860 children 0
      
      testcase4: grandchild maxrss
        expect: post_wait.children ~= 300MB
      initial: self 103564 children 154860
      grandchild alloc 300MB
      post_wait: self 103564 children 308720
      
      testcase5: zombie
        expect: pre_wait ~= initial, IOW the zombie process is not accounted.
                post_wait ~= 400MB, IOW wait() collect child's max_rss.
      initial: self 103564 children 308720
      child alloc 400MB
      pre_wait: self 103564 children 308720
      post_wait: self 103564 children 411312
      
      testcase6: SIG_IGN
        expect: initial ~= after_zombie (child's 500MB alloc should be ignored).
      initial: self 103564 children 411312
      child alloc 500MB
      after_zombie: self 103624 children 411312
      
      testcase7: exec (without fork)
        expect: initial ~= exec
      initial: self 103624 children 411312
      exec: self 103624 children 411312
      
      Linux result (actual test result)
      ========================================================
      allocate 100MB
      testcase1: fork inherit?
        expect: initial.self ~= child.self
      initial: self 102848 children 0
      fork child: self 102572 children 0
      
      testcase2: fork inherit? (cont.)
        expect: initial.children ~= 100MB, but child.children = 0
      initial: self 102876 children 102644
      child: self 102572 children 0
      
      testcase3: fork + malloc
        expect: child.self ~= initial.self + 50MB
      initial: self 102876 children 102644
      allocate +50MB
      fork child: self 153804 children 0
      
      testcase4: grandchild maxrss
        expect: post_wait.children ~= 300MB
      initial: self 102876 children 153864
      grandchild alloc 300MB
      post_wait: self 102876 children 307536
      
      testcase5: zombie
        expect: pre_wait ~= initial, IOW the zombie process is not accounted.
                post_wait ~= 400MB, IOW wait() collect child's max_rss.
      initial: self 102876 children 307536
      child alloc 400MB
      pre_wait: self 102876 children 307536
      post_wait: self 102876 children 410076
      
      testcase6: SIG_IGN
        expect: initial ~= after_zombie (child's 500MB alloc should be ignored).
      initial: self 102876 children 410076
      child alloc 500MB
      after_zombie: self 102880 children 410076
      
      testcase7: exec (without fork)
        expect: initial ~= exec
      initial: self 102880 children 410076
      exec: self 102880 children 410076
      Signed-off-by: NJiri Pirko <jpirko@redhat.com>
      Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1f10206c
  2. 21 9月, 2009 1 次提交
    • I
      perf: Do the big rename: Performance Counters -> Performance Events · cdd6c482
      Ingo Molnar 提交于
      Bye-bye Performance Counters, welcome Performance Events!
      
      In the past few months the perfcounters subsystem has grown out its
      initial role of counting hardware events, and has become (and is
      becoming) a much broader generic event enumeration, reporting, logging,
      monitoring, analysis facility.
      
      Naming its core object 'perf_counter' and naming the subsystem
      'perfcounters' has become more and more of a misnomer. With pending
      code like hw-breakpoints support the 'counter' name is less and
      less appropriate.
      
      All in one, we've decided to rename the subsystem to 'performance
      events' and to propagate this rename through all fields, variables
      and API names. (in an ABI compatible fashion)
      
      The word 'event' is also a bit shorter than 'counter' - which makes
      it slightly more convenient to write/handle as well.
      
      Thanks goes to Stephane Eranian who first observed this misnomer and
      suggested a rename.
      
      User-space tooling and ABI compatibility is not affected - this patch
      should be function-invariant. (Also, defconfigs were not touched to
      keep the size down.)
      
      This patch has been generated via the following script:
      
        FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
      
        sed -i \
          -e 's/PERF_EVENT_/PERF_RECORD_/g' \
          -e 's/PERF_COUNTER/PERF_EVENT/g' \
          -e 's/perf_counter/perf_event/g' \
          -e 's/nb_counters/nb_events/g' \
          -e 's/swcounter/swevent/g' \
          -e 's/tpcounter_event/tp_event/g' \
          $FILES
      
        for N in $(find . -name perf_counter.[ch]); do
          M=$(echo $N | sed 's/perf_counter/perf_event/g')
          mv $N $M
        done
      
        FILES=$(find . -name perf_event.*)
      
        sed -i \
          -e 's/COUNTER_MASK/REG_MASK/g' \
          -e 's/COUNTER/EVENT/g' \
          -e 's/\<event\>/event_id/g' \
          -e 's/counter/event/g' \
          -e 's/Counter/Event/g' \
          $FILES
      
      ... to keep it as correct as possible. This script can also be
      used by anyone who has pending perfcounters patches - it converts
      a Linux kernel tree over to the new naming. We tried to time this
      change to the point in time where the amount of pending patches
      is the smallest: the end of the merge window.
      
      Namespace clashes were fixed up in a preparatory patch - and some
      stylistic fallout will be fixed up in a subsequent patch.
      
      ( NOTE: 'counters' are still the proper terminology when we deal
        with hardware registers - and these sed scripts are a bit
        over-eager in renaming them. I've undone some of that, but
        in case there's something left where 'counter' would be
        better than 'event' we can undo that on an individual basis
        instead of touching an otherwise nicely automated patch. )
      Suggested-by: NStephane Eranian <eranian@google.com>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NPaul Mackerras <paulus@samba.org>
      Reviewed-by: NArjan van de Ven <arjan@linux.intel.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Kyle McMartin <kyle@mcmartin.ca>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: <linux-arch@vger.kernel.org>
      LKML-Reference: <new-submission>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      cdd6c482
  3. 06 9月, 2009 1 次提交
    • O
      exec: do not sleep in TASK_TRACED under ->cred_guard_mutex · a2a8474c
      Oleg Nesterov 提交于
      Tom Horsley reports that his debugger hangs when it tries to read
      /proc/pid_of_tracee/maps, this happens since
      
      	"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
      	04b836cbf19e885f8366bccb2e4b0474346c02d
      
      commit in 2.6.31.
      
      But the root of the problem lies in the fact that do_execve() path calls
      tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.
      
      The tracee must not sleep in TASK_TRACED holding this mutex.  Even if we
      remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
      another task doing PTRACE_ATTACH should not hang until it is killed or the
      tracee resumes.
      
      With this patch do_execve() does not use ->cred_guard_mutex directly and
      we do not hold it throughout, instead:
      
      	- introduce prepare_bprm_creds() helper, it locks the mutex
      	  and calls prepare_exec_creds() to initialize bprm->cred.
      
      	- install_exec_creds() drops the mutex after commit_creds(),
      	  and thus before tracehook_report_exec()->ptrace_stop().
      
      	  or, if exec fails,
      
      	  free_bprm() drops this mutex when bprm->cred != NULL which
      	  indicates install_exec_creds() was not called.
      Reported-by: NTom Horsley <tom.horsley@att.net>
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Acked-by: NDavid Howells <dhowells@redhat.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: James Morris <jmorris@namei.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a2a8474c
  4. 24 8月, 2009 1 次提交
  5. 07 7月, 2009 1 次提交
  6. 22 5月, 2009 1 次提交
  7. 11 5月, 2009 1 次提交
  8. 09 5月, 2009 2 次提交
  9. 03 5月, 2009 1 次提交
    • I
      alpha: binfmt_aout fix · 74641f58
      Ivan Kokshaysky 提交于
      This fixes the problem introduced by commit 3bfacef4 (get rid of
      special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults
      when binfmt_aout built as module.  That happens because aout binary
      handler gets on the top of the binfmt list due to late registration, and
      kernel attempts to execute the binary without preparatory work that must
      be done by binfmt_loader.
      
      Fixed by changing the registration order of the default binfmt handlers
      using list_add_tail() and introducing insert_binfmt() function which
      places new handler on the top of the binfmt list.  This might be generally
      useful for installing arch-specific frontends for default handlers or just
      for overriding them.
      Signed-off-by: NIvan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Al Viro <viro@ZenIV.linux.org.uk>
      Cc: Richard Henderson <rth@twiddle.net
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      74641f58
  10. 24 4月, 2009 2 次提交
    • O
      check_unsafe_exec: s/lock_task_sighand/rcu_read_lock/ · 437f7fdb
      Oleg Nesterov 提交于
      write_lock(&current->fs->lock) guarantees we can't wrongly miss
      LSM_UNSAFE_SHARE, this is what we care about. Use rcu_read_lock()
      instead of ->siglock to iterate over the sub-threads. We must see
      all CLONE_THREAD|CLONE_FS threads which didn't pass exit_fs(), it
      takes fs->lock too.
      
      With or without this patch we can miss the freshly cloned thread
      and set LSM_UNSAFE_SHARE, we don't care.
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Acked-by: NRoland McGrath <roland@redhat.com>
      [ Fixed lock/unlock typo  - Hugh ]
      Acked-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      437f7fdb
    • O
      do_execve() must not clear fs->in_exec if it was set by another thread · 8c652f96
      Oleg Nesterov 提交于
      If do_execve() fails after check_unsafe_exec(), it clears fs->in_exec
      unconditionally. This is wrong if we race with our sub-thread which
      also does do_execve:
      
      	Two threads T1 and T2 and another process P, all share the same
      	->fs.
      
      	T1 starts do_execve(BAD_FILE). It calls check_unsafe_exec(), since
      	->fs is shared, we set LSM_UNSAFE but not ->in_exec.
      
      	P exits and decrements fs->users.
      
      	T2 starts do_execve(), calls check_unsafe_exec(), now ->fs is not
      	shared, we set fs->in_exec.
      
      	T1 continues, open_exec(BAD_FILE) fails, we clear ->in_exec and
      	return to the user-space.
      
      	T1 does clone(CLONE_FS /* without CLONE_THREAD */).
      
      	T2 continues without LSM_UNSAFE_SHARE while ->fs is shared with
      	another process.
      
      Change check_unsafe_exec() to return res = 1 if we set ->in_exec, and change
      do_execve() to clear ->in_exec depending on res.
      
      When do_execve() suceeds, it is safe to clear ->in_exec unconditionally.
      It can be set only if we don't share ->fs with another process, and since
      we already killed all sub-threads either ->in_exec == 0 or we are the
      only user of this ->fs.
      
      Also, we do not need fs->lock to clear fs->in_exec.
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Acked-by: NRoland McGrath <roland@redhat.com>
      Acked-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8c652f96
  11. 09 4月, 2009 1 次提交
  12. 01 4月, 2009 3 次提交
  13. 29 3月, 2009 1 次提交
    • H
      fix setuid sometimes doesn't · e426b64c
      Hugh Dickins 提交于
      Joe Malicki reports that setuid sometimes doesn't: very rarely,
      a setuid root program does not get root euid; and, by the way,
      they have a health check running lsof every few minutes.
      
      Right, check_unsafe_exec() notes whether the files_struct is being
      shared by more threads than will get killed by the exec, and if so
      sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
      But /proc/<pid>/fd and /proc/<pid>/fdinfo lookups make transient
      use of get_files_struct(), which also raises that sharing count.
      
      There's a rather simple fix for this: exec's check on files->count
      has been redundant ever since 2.6.1 made it unshare_files() (except
      while compat_do_execve() omitted to do so) - just remove that check.
      
      [Note to -stable: this patch will not apply before 2.6.29: earlier
      releases should just remove the files->count line from unsafe_exec().]
      Reported-by: NJoe Malicki <jmalicki@metacarta.com>
      Narrowed-down-by: NMichael Itz <mitz@metacarta.com>
      Tested-by: NJoe Malicki <jmalicki@metacarta.com>
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Cc: stable@kernel.org
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e426b64c
  14. 12 2月, 2009 1 次提交
  15. 07 2月, 2009 1 次提交
    • D
      CRED: Fix SUID exec regression · 0bf2f3ae
      David Howells 提交于
      The patch:
      
      	commit a6f76f23
      	CRED: Make execve() take advantage of copy-on-write credentials
      
      moved the place in which the 'safeness' of a SUID/SGID exec was performed to
      before de_thread() was called.  This means that LSM_UNSAFE_SHARE is now
      calculated incorrectly.  This flag is set if any of the usage counts for
      fs_struct, files_struct and sighand_struct are greater than 1 at the time the
      determination is made.  All of which are true for threads created by the
      pthread library.
      
      However, since we wish to make the security calculation before irrevocably
      damaging the process so that we can return it an error code in the case where
      we decide we want to reject the exec request on this basis, we have to make the
      determination before calling de_thread().
      
      So, instead, we count up the number of threads (CLONE_THREAD) that are sharing
      our fs_struct (CLONE_FS), files_struct (CLONE_FILES) and sighand_structs
      (CLONE_SIGHAND/CLONE_THREAD) with us.  These will be killed by de_thread() and
      so can be discounted by check_unsafe_exec().
      
      We do have to be careful because CLONE_THREAD does not imply FS or FILES.
      
      We _assume_ that there will be no extra references to these structs held by the
      threads we're going to kill.
      
      This can be tested with the attached pair of programs.  Build the two programs
      using the Makefile supplied, and run ./test1 as a non-root user.  If
      successful, you should see something like:
      
      	[dhowells@andromeda tmp]$ ./test1
      	--TEST1--
      	uid=4043, euid=4043 suid=4043
      	exec ./test2
      	--TEST2--
      	uid=4043, euid=0 suid=0
      	SUCCESS - Correct effective user ID
      
      and if unsuccessful, something like:
      
      	[dhowells@andromeda tmp]$ ./test1
      	--TEST1--
      	uid=4043, euid=4043 suid=4043
      	exec ./test2
      	--TEST2--
      	uid=4043, euid=4043 suid=4043
      	ERROR - Incorrect effective user ID!
      
      The non-root user ID you see will depend on the user you run as.
      
      [test1.c]
      #include <stdio.h>
      #include <stdlib.h>
      #include <unistd.h>
      #include <pthread.h>
      
      static void *thread_func(void *arg)
      {
      	while (1) {}
      }
      
      int main(int argc, char **argv)
      {
      	pthread_t tid;
      	uid_t uid, euid, suid;
      
      	printf("--TEST1--\n");
      	getresuid(&uid, &euid, &suid);
      	printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);
      
      	if (pthread_create(&tid, NULL, thread_func, NULL) < 0) {
      		perror("pthread_create");
      		exit(1);
      	}
      
      	printf("exec ./test2\n");
      	execlp("./test2", "test2", NULL);
      	perror("./test2");
      	_exit(1);
      }
      
      [test2.c]
      #include <stdio.h>
      #include <stdlib.h>
      #include <unistd.h>
      
      int main(int argc, char **argv)
      {
      	uid_t uid, euid, suid;
      
      	getresuid(&uid, &euid, &suid);
      	printf("--TEST2--\n");
      	printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);
      
      	if (euid != 0) {
      		fprintf(stderr, "ERROR - Incorrect effective user ID!\n");
      		exit(1);
      	}
      	printf("SUCCESS - Correct effective user ID\n");
      	exit(0);
      }
      
      [Makefile]
      CFLAGS = -D_GNU_SOURCE -Wall -Werror -Wunused
      all: test1 test2
      
      test1: test1.c
      	gcc $(CFLAGS) -o test1 test1.c -lpthread
      
      test2: test2.c
      	gcc $(CFLAGS) -o test2 test2.c
      	sudo chown root.root test2
      	sudo chmod +s test2
      Reported-by: NDavid Smith <dsmith@redhat.com>
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NDavid Smith <dsmith@redhat.com>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      0bf2f3ae
  16. 06 2月, 2009 1 次提交
  17. 14 1月, 2009 1 次提交
  18. 07 1月, 2009 3 次提交
  19. 06 1月, 2009 1 次提交
  20. 04 1月, 2009 1 次提交
  21. 01 1月, 2009 1 次提交
  22. 16 12月, 2008 1 次提交
  23. 13 12月, 2008 1 次提交
  24. 10 12月, 2008 1 次提交
    • R
      tracehook: exec double-reporting fix · 85f33466
      Roland McGrath 提交于
      The patch 6341c393 "tracehook: exec" introduced a small regression in
      2.6.27 regarding binfmt_misc exec event reporting.  Since the reporting
      is now done in the common search_binary_handler() function, an exec
      of a misc binary will result in two (or possibly multiple) exec events
      being reported, instead of just a single one, because the misc handler
      contains a recursive call to search_binary_handler.
      
      To add to the confusion, if PTRACE_O_TRACEEXEC is not active, the multiple
      SIGTRAP signals will in fact cause only a single ptrace intercept, as the
      signals are not queued.  However, if PTRACE_O_TRACEEXEC is on, the debugger
      will actually see multiple ptrace intercepts (PTRACE_EVENT_EXEC).
      
      The test program included below demonstrates the problem.
      
      This change fixes the bug by calling tracehook_report_exec() only in the
      outermost search_binary_handler() call (bprm->recursion_depth == 0).
      
      The additional change to restore bprm->recursion_depth after each binfmt
      load_binary call is actually superfluous for this bug, since we test the
      value saved on entry to search_binary_handler().  But it keeps the use of
      of the depth count to its most obvious expected meaning.  Depending on what
      binfmt handlers do in certain cases, there could have been false-positive
      tests for recursion limits before this change.
      
          /* Test program using PTRACE_O_TRACEEXEC.
             This forks and exec's the first argument with the rest of the arguments,
             while ptrace'ing.  It expects to see one PTRACE_EVENT_EXEC stop and
             then a successful exit, with no other signals or events in between.
      
             Test for kernel doing two PTRACE_EVENT_EXEC stops for a binfmt_misc exec:
      
             $ gcc -g traceexec.c -o traceexec
             $ sudo sh -c 'echo :test:M::foobar::/bin/cat: > /proc/sys/fs/binfmt_misc/register'
             $ echo 'foobar test' > ./foobar
             $ chmod +x ./foobar
             $ ./traceexec ./foobar; echo $?
             ==> good <==
             foobar test
             0
             $
             ==> bad <==
             foobar test
             unexpected status 0x4057f != 0
             3
             $
      
          */
      
          #include <stdio.h>
          #include <sys/types.h>
          #include <sys/wait.h>
          #include <sys/ptrace.h>
          #include <unistd.h>
          #include <signal.h>
          #include <stdlib.h>
      
          static void
          wait_for (pid_t child, int expect)
          {
            int status;
            pid_t p = wait (&status);
            if (p != child)
      	{
      	  perror ("wait");
      	  exit (2);
      	}
            if (status != expect)
      	{
      	  fprintf (stderr, "unexpected status %#x != %#x\n", status, expect);
      	  exit (3);
      	}
          }
      
          int
          main (int argc, char **argv)
          {
            pid_t child = fork ();
      
            if (child < 0)
      	{
      	  perror ("fork");
      	  return 127;
      	}
            else if (child == 0)
      	{
      	  ptrace (PTRACE_TRACEME);
      	  raise (SIGUSR1);
      	  execv (argv[1], &argv[1]);
      	  perror ("execve");
      	  _exit (127);
      	}
      
            wait_for (child, W_STOPCODE (SIGUSR1));
      
            if (ptrace (PTRACE_SETOPTIONS, child,
      		  0L, (void *) (long) PTRACE_O_TRACEEXEC) != 0)
      	{
      	  perror ("PTRACE_SETOPTIONS");
      	  return 4;
      	}
      
            if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
      	{
      	  perror ("PTRACE_CONT");
      	  return 5;
      	}
      
            wait_for (child, W_STOPCODE (SIGTRAP | (PTRACE_EVENT_EXEC << 8)));
      
            if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
      	{
      	  perror ("PTRACE_CONT");
      	  return 6;
      	}
      
            wait_for (child, W_EXITCODE (0, 0));
      
            return 0;
          }
      Reported-by: NArnd Bergmann <arnd@arndb.de>
      CC: Ulrich Weigand <ulrich.weigand@de.ibm.com>
      Signed-off-by: NRoland McGrath <roland@redhat.com>
      85f33466
  25. 14 11月, 2008 5 次提交
    • D
      CRED: Make execve() take advantage of copy-on-write credentials · a6f76f23
      David Howells 提交于
      Make execve() take advantage of copy-on-write credentials, allowing it to set
      up the credentials in advance, and then commit the whole lot after the point
      of no return.
      
      This patch and the preceding patches have been tested with the LTP SELinux
      testsuite.
      
      This patch makes several logical sets of alteration:
      
       (1) execve().
      
           The credential bits from struct linux_binprm are, for the most part,
           replaced with a single credentials pointer (bprm->cred).  This means that
           all the creds can be calculated in advance and then applied at the point
           of no return with no possibility of failure.
      
           I would like to replace bprm->cap_effective with:
      
      	cap_isclear(bprm->cap_effective)
      
           but this seems impossible due to special behaviour for processes of pid 1
           (they always retain their parent's capability masks where normally they'd
           be changed - see cap_bprm_set_creds()).
      
           The following sequence of events now happens:
      
           (a) At the start of do_execve, the current task's cred_exec_mutex is
           	 locked to prevent PTRACE_ATTACH from obsoleting the calculation of
           	 creds that we make.
      
           (a) prepare_exec_creds() is then called to make a copy of the current
           	 task's credentials and prepare it.  This copy is then assigned to
           	 bprm->cred.
      
        	 This renders security_bprm_alloc() and security_bprm_free()
           	 unnecessary, and so they've been removed.
      
           (b) The determination of unsafe execution is now performed immediately
           	 after (a) rather than later on in the code.  The result is stored in
           	 bprm->unsafe for future reference.
      
           (c) prepare_binprm() is called, possibly multiple times.
      
           	 (i) This applies the result of set[ug]id binaries to the new creds
           	     attached to bprm->cred.  Personality bit clearance is recorded,
           	     but now deferred on the basis that the exec procedure may yet
           	     fail.
      
               (ii) This then calls the new security_bprm_set_creds().  This should
      	     calculate the new LSM and capability credentials into *bprm->cred.
      
      	     This folds together security_bprm_set() and parts of
      	     security_bprm_apply_creds() (these two have been removed).
      	     Anything that might fail must be done at this point.
      
               (iii) bprm->cred_prepared is set to 1.
      
      	     bprm->cred_prepared is 0 on the first pass of the security
      	     calculations, and 1 on all subsequent passes.  This allows SELinux
      	     in (ii) to base its calculations only on the initial script and
      	     not on the interpreter.
      
           (d) flush_old_exec() is called to commit the task to execution.  This
           	 performs the following steps with regard to credentials:
      
      	 (i) Clear pdeath_signal and set dumpable on certain circumstances that
      	     may not be covered by commit_creds().
      
               (ii) Clear any bits in current->personality that were deferred from
                   (c.i).
      
           (e) install_exec_creds() [compute_creds() as was] is called to install the
           	 new credentials.  This performs the following steps with regard to
           	 credentials:
      
               (i) Calls security_bprm_committing_creds() to apply any security
                   requirements, such as flushing unauthorised files in SELinux, that
                   must be done before the credentials are changed.
      
      	     This is made up of bits of security_bprm_apply_creds() and
      	     security_bprm_post_apply_creds(), both of which have been removed.
      	     This function is not allowed to fail; anything that might fail
      	     must have been done in (c.ii).
      
               (ii) Calls commit_creds() to apply the new credentials in a single
                   assignment (more or less).  Possibly pdeath_signal and dumpable
                   should be part of struct creds.
      
      	 (iii) Unlocks the task's cred_replace_mutex, thus allowing
      	     PTRACE_ATTACH to take place.
      
               (iv) Clears The bprm->cred pointer as the credentials it was holding
                   are now immutable.
      
               (v) Calls security_bprm_committed_creds() to apply any security
                   alterations that must be done after the creds have been changed.
                   SELinux uses this to flush signals and signal handlers.
      
           (f) If an error occurs before (d.i), bprm_free() will call abort_creds()
           	 to destroy the proposed new credentials and will then unlock
           	 cred_replace_mutex.  No changes to the credentials will have been
           	 made.
      
       (2) LSM interface.
      
           A number of functions have been changed, added or removed:
      
           (*) security_bprm_alloc(), ->bprm_alloc_security()
           (*) security_bprm_free(), ->bprm_free_security()
      
           	 Removed in favour of preparing new credentials and modifying those.
      
           (*) security_bprm_apply_creds(), ->bprm_apply_creds()
           (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
      
           	 Removed; split between security_bprm_set_creds(),
           	 security_bprm_committing_creds() and security_bprm_committed_creds().
      
           (*) security_bprm_set(), ->bprm_set_security()
      
           	 Removed; folded into security_bprm_set_creds().
      
           (*) security_bprm_set_creds(), ->bprm_set_creds()
      
           	 New.  The new credentials in bprm->creds should be checked and set up
           	 as appropriate.  bprm->cred_prepared is 0 on the first call, 1 on the
           	 second and subsequent calls.
      
           (*) security_bprm_committing_creds(), ->bprm_committing_creds()
           (*) security_bprm_committed_creds(), ->bprm_committed_creds()
      
           	 New.  Apply the security effects of the new credentials.  This
           	 includes closing unauthorised files in SELinux.  This function may not
           	 fail.  When the former is called, the creds haven't yet been applied
           	 to the process; when the latter is called, they have.
      
       	 The former may access bprm->cred, the latter may not.
      
       (3) SELinux.
      
           SELinux has a number of changes, in addition to those to support the LSM
           interface changes mentioned above:
      
           (a) The bprm_security_struct struct has been removed in favour of using
           	 the credentials-under-construction approach.
      
           (c) flush_unauthorized_files() now takes a cred pointer and passes it on
           	 to inode_has_perm(), file_has_perm() and dentry_open().
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NJames Morris <jmorris@namei.org>
      Acked-by: NSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      a6f76f23
    • D
      CRED: Inaugurate COW credentials · d84f4f99
      David Howells 提交于
      Inaugurate copy-on-write credentials management.  This uses RCU to manage the
      credentials pointer in the task_struct with respect to accesses by other tasks.
      A process may only modify its own credentials, and so does not need locking to
      access or modify its own credentials.
      
      A mutex (cred_replace_mutex) is added to the task_struct to control the effect
      of PTRACE_ATTACHED on credential calculations, particularly with respect to
      execve().
      
      With this patch, the contents of an active credentials struct may not be
      changed directly; rather a new set of credentials must be prepared, modified
      and committed using something like the following sequence of events:
      
      	struct cred *new = prepare_creds();
      	int ret = blah(new);
      	if (ret < 0) {
      		abort_creds(new);
      		return ret;
      	}
      	return commit_creds(new);
      
      There are some exceptions to this rule: the keyrings pointed to by the active
      credentials may be instantiated - keyrings violate the COW rule as managing
      COW keyrings is tricky, given that it is possible for a task to directly alter
      the keys in a keyring in use by another task.
      
      To help enforce this, various pointers to sets of credentials, such as those in
      the task_struct, are declared const.  The purpose of this is compile-time
      discouragement of altering credentials through those pointers.  Once a set of
      credentials has been made public through one of these pointers, it may not be
      modified, except under special circumstances:
      
        (1) Its reference count may incremented and decremented.
      
        (2) The keyrings to which it points may be modified, but not replaced.
      
      The only safe way to modify anything else is to create a replacement and commit
      using the functions described in Documentation/credentials.txt (which will be
      added by a later patch).
      
      This patch and the preceding patches have been tested with the LTP SELinux
      testsuite.
      
      This patch makes several logical sets of alteration:
      
       (1) execve().
      
           This now prepares and commits credentials in various places in the
           security code rather than altering the current creds directly.
      
       (2) Temporary credential overrides.
      
           do_coredump() and sys_faccessat() now prepare their own credentials and
           temporarily override the ones currently on the acting thread, whilst
           preventing interference from other threads by holding cred_replace_mutex
           on the thread being dumped.
      
           This will be replaced in a future patch by something that hands down the
           credentials directly to the functions being called, rather than altering
           the task's objective credentials.
      
       (3) LSM interface.
      
           A number of functions have been changed, added or removed:
      
           (*) security_capset_check(), ->capset_check()
           (*) security_capset_set(), ->capset_set()
      
           	 Removed in favour of security_capset().
      
           (*) security_capset(), ->capset()
      
           	 New.  This is passed a pointer to the new creds, a pointer to the old
           	 creds and the proposed capability sets.  It should fill in the new
           	 creds or return an error.  All pointers, barring the pointer to the
           	 new creds, are now const.
      
           (*) security_bprm_apply_creds(), ->bprm_apply_creds()
      
           	 Changed; now returns a value, which will cause the process to be
           	 killed if it's an error.
      
           (*) security_task_alloc(), ->task_alloc_security()
      
           	 Removed in favour of security_prepare_creds().
      
           (*) security_cred_free(), ->cred_free()
      
           	 New.  Free security data attached to cred->security.
      
           (*) security_prepare_creds(), ->cred_prepare()
      
           	 New. Duplicate any security data attached to cred->security.
      
           (*) security_commit_creds(), ->cred_commit()
      
           	 New. Apply any security effects for the upcoming installation of new
           	 security by commit_creds().
      
           (*) security_task_post_setuid(), ->task_post_setuid()
      
           	 Removed in favour of security_task_fix_setuid().
      
           (*) security_task_fix_setuid(), ->task_fix_setuid()
      
           	 Fix up the proposed new credentials for setuid().  This is used by
           	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
           	 setuid() changes.  Changes are made to the new credentials, rather
           	 than the task itself as in security_task_post_setuid().
      
           (*) security_task_reparent_to_init(), ->task_reparent_to_init()
      
           	 Removed.  Instead the task being reparented to init is referred
           	 directly to init's credentials.
      
      	 NOTE!  This results in the loss of some state: SELinux's osid no
      	 longer records the sid of the thread that forked it.
      
           (*) security_key_alloc(), ->key_alloc()
           (*) security_key_permission(), ->key_permission()
      
           	 Changed.  These now take cred pointers rather than task pointers to
           	 refer to the security context.
      
       (4) sys_capset().
      
           This has been simplified and uses less locking.  The LSM functions it
           calls have been merged.
      
       (5) reparent_to_kthreadd().
      
           This gives the current thread the same credentials as init by simply using
           commit_thread() to point that way.
      
       (6) __sigqueue_alloc() and switch_uid()
      
           __sigqueue_alloc() can't stop the target task from changing its creds
           beneath it, so this function gets a reference to the currently applicable
           user_struct which it then passes into the sigqueue struct it returns if
           successful.
      
           switch_uid() is now called from commit_creds(), and possibly should be
           folded into that.  commit_creds() should take care of protecting
           __sigqueue_alloc().
      
       (7) [sg]et[ug]id() and co and [sg]et_current_groups.
      
           The set functions now all use prepare_creds(), commit_creds() and
           abort_creds() to build and check a new set of credentials before applying
           it.
      
           security_task_set[ug]id() is called inside the prepared section.  This
           guarantees that nothing else will affect the creds until we've finished.
      
           The calling of set_dumpable() has been moved into commit_creds().
      
           Much of the functionality of set_user() has been moved into
           commit_creds().
      
           The get functions all simply access the data directly.
      
       (8) security_task_prctl() and cap_task_prctl().
      
           security_task_prctl() has been modified to return -ENOSYS if it doesn't
           want to handle a function, or otherwise return the return value directly
           rather than through an argument.
      
           Additionally, cap_task_prctl() now prepares a new set of credentials, even
           if it doesn't end up using it.
      
       (9) Keyrings.
      
           A number of changes have been made to the keyrings code:
      
           (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
           	 all been dropped and built in to the credentials functions directly.
           	 They may want separating out again later.
      
           (b) key_alloc() and search_process_keyrings() now take a cred pointer
           	 rather than a task pointer to specify the security context.
      
           (c) copy_creds() gives a new thread within the same thread group a new
           	 thread keyring if its parent had one, otherwise it discards the thread
           	 keyring.
      
           (d) The authorisation key now points directly to the credentials to extend
           	 the search into rather pointing to the task that carries them.
      
           (e) Installing thread, process or session keyrings causes a new set of
           	 credentials to be created, even though it's not strictly necessary for
           	 process or session keyrings (they're shared).
      
      (10) Usermode helper.
      
           The usermode helper code now carries a cred struct pointer in its
           subprocess_info struct instead of a new session keyring pointer.  This set
           of credentials is derived from init_cred and installed on the new process
           after it has been cloned.
      
           call_usermodehelper_setup() allocates the new credentials and
           call_usermodehelper_freeinfo() discards them if they haven't been used.  A
           special cred function (prepare_usermodeinfo_creds()) is provided
           specifically for call_usermodehelper_setup() to call.
      
           call_usermodehelper_setkeys() adjusts the credentials to sport the
           supplied keyring as the new session keyring.
      
      (11) SELinux.
      
           SELinux has a number of changes, in addition to those to support the LSM
           interface changes mentioned above:
      
           (a) selinux_setprocattr() no longer does its check for whether the
           	 current ptracer can access processes with the new SID inside the lock
           	 that covers getting the ptracer's SID.  Whilst this lock ensures that
           	 the check is done with the ptracer pinned, the result is only valid
           	 until the lock is released, so there's no point doing it inside the
           	 lock.
      
      (12) is_single_threaded().
      
           This function has been extracted from selinux_setprocattr() and put into
           a file of its own in the lib/ directory as join_session_keyring() now
           wants to use it too.
      
           The code in SELinux just checked to see whether a task shared mm_structs
           with other tasks (CLONE_VM), but that isn't good enough.  We really want
           to know if they're part of the same thread group (CLONE_THREAD).
      
      (13) nfsd.
      
           The NFS server daemon now has to use the COW credentials to set the
           credentials it is going to use.  It really needs to pass the credentials
           down to the functions it calls, but it can't do that until other patches
           in this series have been applied.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NJames Morris <jmorris@namei.org>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      d84f4f99
    • D
      CRED: Wrap current->cred and a few other accessors · 86a264ab
      David Howells 提交于
      Wrap current->cred and a few other accessors to hide their actual
      implementation.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NJames Morris <jmorris@namei.org>
      Acked-by: NSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      86a264ab
    • D
      CRED: Separate task security context from task_struct · b6dff3ec
      David Howells 提交于
      Separate the task security context from task_struct.  At this point, the
      security data is temporarily embedded in the task_struct with two pointers
      pointing to it.
      
      Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
      entry.S via asm-offsets.
      
      With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NJames Morris <jmorris@namei.org>
      Acked-by: NSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      b6dff3ec
    • D
      CRED: Wrap task credential accesses in the filesystem subsystem · da9592ed
      David Howells 提交于
      Wrap access to task credentials so that they can be separated more easily from
      the task_struct during the introduction of COW creds.
      
      Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
      
      Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
      sense to use RCU directly rather than a convenient wrapper; these will be
      addressed by later patches.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Reviewed-by: NJames Morris <jmorris@namei.org>
      Acked-by: NSerge Hallyn <serue@us.ibm.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: NJames Morris <jmorris@namei.org>
      da9592ed
  26. 20 10月, 2008 1 次提交
  27. 17 10月, 2008 3 次提交
  28. 16 10月, 2008 1 次提交