[sanitizer] Ptrace syscall handler.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@193633 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 49 insertions, 2 deletions

diff --git a/lib/msan/lit_tests/Linux/syscalls.cc b/lib/msan/lit_tests/Linux/syscalls.cc
index 962fba3e..797832d8 100644
--- a/lib/msan/lit_tests/Linux/syscalls.cc
+++ b/lib/msan/lit_tests/Linux/syscalls.cc
@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include <sys/ptrace.h>
 #include <sys/stat.h>
 
 #include <sanitizer/linux_syscall_hooks.h>
@@ -76,6 +77,10 @@ int main(int argc, char *argv[]) {
   __sanitizer_syscall_post_mq_timedreceive(kFortyTwo, 5, buf, sizeof(buf), &prio, 0);
   assert(__msan_test_shadow(buf, sizeof(buf)) == kFortyTwo);
   assert(__msan_test_shadow(&prio, sizeof(prio)) == -1);
+
+  __msan_poison(buf, sizeof(buf));
+  __sanitizer_syscall_post_ptrace(0, PTRACE_PEEKUSER, kFortyTwo, 0xABCD, buf);
+  assert(__msan_test_shadow(buf, sizeof(buf)) == sizeof(void *));
   
   return 0;
 }
diff --git a/lib/sanitizer_common/sanitizer_common_syscalls.inc b/lib/sanitizer_common/sanitizer_common_syscalls.inc
index 0f500d63..baa1d5be 100644
--- a/lib/sanitizer_common/sanitizer_common_syscalls.inc
+++ b/lib/sanitizer_common/sanitizer_common_syscalls.inc
@@ -2218,9 +2218,45 @@ PRE_SYSCALL(ni_syscall)() {}
 
 POST_SYSCALL(ni_syscall)(long res) {}
 
-PRE_SYSCALL(ptrace)(long request, long pid, long addr, long data) {}
+PRE_SYSCALL(ptrace)(long request, long pid, long addr, long data) {
+  if (data) {
+    if (request == ptrace_setregs) {
+      PRE_READ((void *)data, struct_user_regs_struct_sz);
+    } else if (request == ptrace_setfpregs) {
+      PRE_READ((void *)data, struct_user_fpregs_struct_sz);
+    } else if (request == ptrace_setfpxregs) {
+      PRE_READ((void *)data, struct_user_fpxregs_struct_sz);
+    } else if (request == ptrace_setsiginfo) {
+      PRE_READ((void *)data, siginfo_t_sz);
+    } else if (request == ptrace_setregset) {
+      __sanitizer_iovec *iov = (__sanitizer_iovec *)data;
+      PRE_READ(iov->iov_base, iov->iov_len);
+    }
+  }
+}
 
-POST_SYSCALL(ptrace)(long res, long request, long pid, long addr, long data) {}
+POST_SYSCALL(ptrace)(long res, long request, long pid, long addr, long data) {
+  if (res >= 0 && data) {
+    // Note that this is different from the interceptor in
+    // sanitizer_common_interceptors.inc.
+    // PEEK* requests return resulting values through data pointer.
+    if (request == ptrace_getregs) {
+      POST_WRITE((void *)data, struct_user_regs_struct_sz);
+    } else if (request == ptrace_getfpregs) {
+      POST_WRITE((void *)data, struct_user_fpregs_struct_sz);
+    } else if (request == ptrace_getfpxregs) {
+      POST_WRITE((void *)data, struct_user_fpxregs_struct_sz);
+    } else if (request == ptrace_getsiginfo) {
+      POST_WRITE((void *)data, siginfo_t_sz);
+    } else if (request == ptrace_getregset) {
+      __sanitizer_iovec *iov = (__sanitizer_iovec *)data;
+      POST_WRITE(iov->iov_base, iov->iov_len);
+    } else if (request == ptrace_peekdata || request == ptrace_peektext ||
+               request == ptrace_peekuser) {
+      POST_WRITE((void *)data, sizeof(void *));
+    }
+  }
+}
 
 PRE_SYSCALL(add_key)(const void *_type, const void *_description,
                      const void *_payload, long plen, long destringid) {
diff --git a/lib/sanitizer_common/sanitizer_platform_limits_posix.cc b/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
index fb932bc1..8276a969 100644
--- a/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -218,6 +218,9 @@ namespace __sanitizer {
   unsigned struct_user_fpxregs_struct_sz = sizeof(struct user_fpxregs_struct);
 #endif
 
+  int ptrace_peektext = PTRACE_PEEKTEXT;
+  int ptrace_peekdata = PTRACE_PEEKDATA;
+  int ptrace_peekuser = PTRACE_PEEKUSER;
   int ptrace_getregs = PTRACE_GETREGS;
   int ptrace_setregs = PTRACE_SETREGS;
   int ptrace_getfpregs = PTRACE_GETFPREGS;
diff --git a/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/lib/sanitizer_common/sanitizer_platform_limits_posix.h
index 0b38d158..6f27ba44 100644
--- a/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -379,6 +379,9 @@ namespace __sanitizer {
   extern unsigned struct_user_fpregs_struct_sz;
   extern unsigned struct_user_fpxregs_struct_sz;
 
+  extern int ptrace_peektext;
+  extern int ptrace_peekdata;
+  extern int ptrace_peekuser;
   extern int ptrace_getregs;
   extern int ptrace_setregs;
   extern int ptrace_getfpregs;