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authorBodo Stroesser <bstroesser@fujitsu-siemens.com>2005-09-03 15:57:13 -0700
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 00:06:19 -0700
commit94c80b2598dbd2b8a6fe5f5c2c3af1beb37f66c7 (patch)
tree7e4221c42418898084961f66670c7f66042f164c
parent08b178ebf37bbfb78329e0ae6ea688b103d205bf (diff)
[PATCH] Ptrace/i386: fix "syscall audit" interaction with singlestep
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Avoid giving two traps for singlestep instead of one, when syscall auditing is enabled. In fact no singlestep trap is sent on syscall entry, only on syscall exit, as can be seen in entry.S: # Note that in this mask _TIF_SINGLESTEP is not tested !!! <<<<<<<<<<<<<< testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),TI_flags(%ebp) jnz syscall_trace_entry ... syscall_trace_entry: ... call do_syscall_trace But auditing a SINGLESTEP'ed process causes do_syscall_trace to be called, so the tracer will get one more trap on the syscall entry path, which it shouldn't. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Roland McGrath <roland@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/ptrace.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
index 0da59b42843c..5ee9e1d60653 100644
--- a/arch/i386/kernel/ptrace.c
+++ b/arch/i386/kernel/ptrace.c
@@ -683,8 +683,19 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit)
/* do the secure computing check first */
secure_computing(regs->orig_eax);
- if (unlikely(current->audit_context) && entryexit)
- audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
+ if (unlikely(current->audit_context)) {
+ if (entryexit)
+ audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
+
+ /* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
+ * on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
+ * not used, entry.S will call us only on syscall exit, not
+ * entry ; so when TIF_SYSCALL_AUDIT is used we must avoid
+ * calling send_sigtrap() on syscall entry.
+ */
+ else if (is_singlestep)
+ goto out;
+ }
if (!(current->ptrace & PT_PTRACED))
goto out;