Messages in this thread Patch in this message | | | Subject | [PATCH 1/2] Fix pollution of task->ptrace if PTRACE_SETOPTIONS fails. | From | Denys Vlasenko <> | Date | Mon, 05 Sep 2011 18:51:03 +0200 |
| |
> A crude patch is below. It rolls points 1-4 from above into a single > new option, PTRACE_O_TRACESTOP.
For easier review, split it into two parts. Part 1 follows. (It is still not even compile-tested). -- vda
Fix pollution of task->ptrace if PTRACE_SETOPTIONS fails.
If PTRACE_SETOPTIONS fails, options should not be affected.
While at it, simplified ptrace_setoptions():
Exchanged PT_TRACESYSGOOD and PT_PTRACE_CAP bit positions, which made PT_option bits contiguous and therefore made ptrace_setoptions much simpler.
PT_EVENT_FLAG_SHIFT was not particularly useful, PT_OPT_FLAG_SHIFT with value of PT_EVENT_FLAG_SHIFT-1 is easier to use.
PT_TRACE_MASK constant is nuked, the only its use is replaced by (PTRACE_O_MASK << PT_OPT_FLAG_SHIFT).
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 800f113..9aa669c 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -88,13 +88,12 @@ #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */ #define PT_PTRACED 0x00000001 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ -#define PT_TRACESYSGOOD 0x00000004 -#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */ +#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */ +#define PT_OPT_FLAG_SHIFT 3 +#define PT_TRACESYSGOOD 0x00000008 /* must be directly before PT_TRACE_event bits! */ /* PT_TRACE_* event enable flags */ -#define PT_EVENT_FLAG_SHIFT 4 -#define PT_EVENT_FLAG(event) (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1)) - +#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event))) #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) @@ -102,8 +101,6 @@ #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) -#define PT_TRACE_MASK 0x000003f4 - /* single stepping state bits (used on ARM and PA-RISC) */ #define PT_SINGLESTEP_BIT 31 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) @@ -228,7 +225,7 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace) child->ptrace = current->ptrace; __ptrace_link(child, current->parent); - if (child->ptrace & PT_SEIZED) + if (child->ptrace & PTRACE_EVENT_STOP) task_set_jobctl_pending(child, JOBCTL_TRAP_STOP); else sigaddset(&child->pending.signal, SIGSTOP); diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 9de3ecf..9c3536d 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -219,19 +219,23 @@ static int ptrace_attach(struct task_struct *task, long request, /* * SEIZE will enable new ptrace behaviors which will be implemented - * gradually. SEIZE_DEVEL is used to prevent applications + * gradually. SEIZE_DEVEL bit is used to prevent applications * expecting full SEIZE behaviors trapping on kernel commits which * are still in the process of implementing them. * * Only test programs for new ptrace behaviors being implemented * should set SEIZE_DEVEL. If unset, SEIZE will fail with -EIO. * - * Once SEIZE behaviors are completely implemented, this flag and - * the following test will be removed. + * Once SEIZE behaviors are completely implemented, this flag + * will be removed. */ retval = -EIO; - if (seize && !(flags & PTRACE_SEIZE_DEVEL)) - goto out; + if (seize) { + if ((flags & ~(long)PTRACE_O_MASK) != PTRACE_SEIZE_DEVEL) + goto out; + flags &= ~PTRACE_SEIZE_DEVEL; + } else + flags = 0; audit_ptrace(task); @@ -243,7 +247,7 @@ static int ptrace_attach(struct task_struct *task, long request, /* * Protect exec's credential calculations against our interference; - * interference; SUID, SGID and LSM creds get determined differently + * SUID, SGID and LSM creds get determined differently * under ptrace. */ retval = -ERESTARTNOINTR; @@ -509,30 +513,13 @@ int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long ds static int ptrace_setoptions(struct task_struct *child, unsigned long data) { - child->ptrace &= ~PT_TRACE_MASK; - - if (data & PTRACE_O_TRACESYSGOOD) - child->ptrace |= PT_TRACESYSGOOD; - - if (data & PTRACE_O_TRACEFORK) - child->ptrace |= PT_TRACE_FORK; - - if (data & PTRACE_O_TRACEVFORK) - child->ptrace |= PT_TRACE_VFORK; - - if (data & PTRACE_O_TRACECLONE) - child->ptrace |= PT_TRACE_CLONE; - - if (data & PTRACE_O_TRACEEXEC) - child->ptrace |= PT_TRACE_EXEC; - - if (data & PTRACE_O_TRACEVFORKDONE) - child->ptrace |= PT_TRACE_VFORK_DONE; + if (data & ~(long)PTRACE_O_MASK) + return -EINVAL; - if (data & PTRACE_O_TRACEEXIT) - child->ptrace |= PT_TRACE_EXIT; + child->ptrace &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); + child->ptrace |= (data << PT_OPT_FLAG_SHIFT); - return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; + return 0; } static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
| |