From 9c1a125921d146f22cf28ff366ff69fd602a0e9b Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Wed, 26 May 2010 14:42:52 -0700 Subject: ptrace: unify FDPIC implementations The Blackfin/FRV/SuperH guys all have the same exact FDPIC ptrace code in their arch handlers (since they were probably copied & pasted). Since these ptrace interfaces are an arch independent aspect of the FDPIC code, unify them in the common ptrace code so new FDPIC ports don't need to copy and paste this fundamental stuff yet again. Signed-off-by: Mike Frysinger Acked-by: Roland McGrath Acked-by: David Howells Acked-by: Paul Mundt Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/ptrace.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel/ptrace.c') diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 6af9cdd558b7..4b4f72084d1b 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -594,6 +594,26 @@ int ptrace_request(struct task_struct *child, long request, ret = ptrace_detach(child, data); break; +#ifdef CONFIG_BINFMT_ELF_FDPIC + case PTRACE_GETFDPIC: { + unsigned long tmp = 0; + + switch (addr) { + case PTRACE_GETFDPIC_EXEC: + tmp = child->mm->context.exec_fdpic_loadmap; + break; + case PTRACE_GETFDPIC_INTERP: + tmp = child->mm->context.interp_fdpic_loadmap; + break; + default: + break; + } + + ret = put_user(tmp, (unsigned long __user *) data); + break; + } +#endif + #ifdef PTRACE_SINGLESTEP case PTRACE_SINGLESTEP: #endif -- cgit v1.2.3 From e0129ef91ed758c06b6557c36124acfb2e1c7305 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 26 May 2010 14:42:53 -0700 Subject: ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Now that Mike Frysinger unified the FDPIC ptrace code, we can fix the unsafe usage of child->mm in ptrace_request(PTRACE_GETFDPIC). We have the reference to task_struct, and ptrace_check_attach() verified the tracee is stopped. But nothing can protect from SIGKILL after that, we must not assume child->mm != NULL. Signed-off-by: Oleg Nesterov Acked-by: Mike Frysinger Acked-by: David Howells Cc: Paul Mundt Cc: Greg Ungerer Acked-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/ptrace.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel/ptrace.c') diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 4b4f72084d1b..74a3d693c196 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -596,18 +596,24 @@ int ptrace_request(struct task_struct *child, long request, #ifdef CONFIG_BINFMT_ELF_FDPIC case PTRACE_GETFDPIC: { + struct mm_struct *mm = get_task_mm(child); unsigned long tmp = 0; + ret = -ESRCH; + if (!mm) + break; + switch (addr) { case PTRACE_GETFDPIC_EXEC: - tmp = child->mm->context.exec_fdpic_loadmap; + tmp = mm->context.exec_fdpic_loadmap; break; case PTRACE_GETFDPIC_INTERP: - tmp = child->mm->context.interp_fdpic_loadmap; + tmp = mm->context.interp_fdpic_loadmap; break; default: break; } + mmput(mm); ret = put_user(tmp, (unsigned long __user *) data); break; -- cgit v1.2.3