linux.git/fs/exec.c, branch v2.6.31

exec: do not sleep in TASK_TRACED under ->cred_guard_mutex

2009-09-05T18:30:42+00:00

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: Tom Horsley 
Signed-off-by: Oleg Nesterov 
Acked-by: David Howells 
Cc: Roland McGrath 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel_read: redefine offset type

2009-08-24T04:58:23+00:00

vfs_read() offset is defined as loff_t, but kernel_read()
offset is only defined as unsigned long. Redefine
kernel_read() offset as loff_t.

Cc: stable@kernel.org
Signed-off-by: Mimi Zohar 
Signed-off-by: James Morris

cred_guard_mutex: do not return -EINTR to user-space

2009-07-06T20:57:04+00:00

do_execve() and ptrace_attach() return -EINTR if
mutex_lock_interruptible(->cred_guard_mutex) fails.

This is not right, change the code to return ERESTARTNOINTR.

Perhaps we should also change proc_pid_attr_write().

Signed-off-by: Oleg Nesterov 
Cc: David Howells 
Acked-by: Roland McGrath 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-06-11T21:01:07+00:00

* 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (574 commits)
  perf_counter: Turn off by default
  perf_counter: Add counter->id to the throttle event
  perf_counter: Better align code
  perf_counter: Rename L2 to LL cache
  perf_counter: Standardize event names
  perf_counter: Rename enums
  perf_counter tools: Clean up u64 usage
  perf_counter: Rename perf_counter_limit sysctl
  perf_counter: More paranoia settings
  perf_counter: powerpc: Implement generalized cache events for POWER processors
  perf_counters: powerpc: Add support for POWER7 processors
  perf_counter: Accurate period data
  perf_counter: Introduce struct for sample data
  perf_counter tools: Normalize data using per sample period data
  perf_counter: Annotate exit ctx recursion
  perf_counter tools: Propagate signals properly
  perf_counter tools: Small frequency related fixes
  perf_counter: More aggressive frequency adjustment
  perf_counter/x86: Fix the model number of Intel Core2 processors
  perf_counter, x86: Correct some event and umask values for Intel processors
  ...

Merge branch 'master' into next

2009-05-22T08:40:59+00:00

Conflicts:
	fs/exec.c

Removed IMA changes (the IMA checks are now performed via may_open()).

Signed-off-by: James Morris

integrity: path_check update

2009-05-21T23:43:41+00:00

- Add support in ima_path_check() for integrity checking without
incrementing the counts. (Required for nfsd.)
- rename and export opencount_get to ima_counts_get
- replace ima_shm_check calls with ima_counts_get
- export ima_path_check

Signed-off-by: Mimi Zohar 
Signed-off-by: James Morris

Merge commit 'v2.6.30-rc6' into perfcounters/core

2009-05-18T05:37:49+00:00

Merge reason: this branch was on an -rc4 base, merge it up to -rc6
              to get the latest upstream fixes.

Signed-off-by: Ingo Molnar

CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace

2009-05-10T22:15:36+00:00

Rename cred_exec_mutex to reflect that it's a guard against foreign
intervention on a process's credential state, such as is made by ptrace().  The
attachment of a debugger to a process affects execve()'s calculation of the new
credential state - _and_ also setprocattr()'s calculation of that state.

Signed-off-by: David Howells 
Signed-off-by: James Morris

Switch open_exec() and sys_uselib() to do_open_filp()

2009-05-09T14:49:42+00:00

... and make path_lookup_open() static

Signed-off-by: Al Viro

Make open_exec() and sys_uselib() use may_open(), instead of duplicating its parts

2009-05-09T14:49:42+00:00

Signed-off-by: Al Viro