[PATCH v3 06/10] socket: Improve fortify with clang

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

It improve fortify checks recv, recvfrom, poll, and ppoll.  The compile
and runtime hecks have similar coverage as with GCC.

Checked on aarch64, armhf, x86_64, and i686.
---
 io/bits/poll2.h       | 29 +++++++++++++++++++++--------
 socket/bits/socket2.h | 20 ++++++++++++++++----
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/io/bits/poll2.h b/io/bits/poll2.h
index 6152a8c5e4..24ec1056eb 100644
--- a/io/bits/poll2.h
+++ b/io/bits/poll2.h
@@ -33,8 +33,13 @@ extern int __REDIRECT (__poll_chk_warn, (struct pollfd *__fds, nfds_t __nfds,
 		       __poll_chk)
   __warnattr ("poll called with fds buffer too small file nfds entries");
 
-__fortify_function __fortified_attr_access (__write_only__, 1, 2) int
-poll (struct pollfd *__fds, nfds_t __nfds, int __timeout)
+__fortify_function __fortified_attr_access (__write_only__, 1, 2)
+__attribute_overloadable__ int
+poll (__fortify_clang_overload_arg (struct pollfd *, ,__fds), nfds_t __nfds,
+      int __timeout)
+     __fortify_clang_warning_only_if_bos_lt2 (__nfds, __fds, sizeof (*__fds),
+					      "poll called with fds buffer "
+					      "too small file nfds entries")
 {
   return __glibc_fortify (poll, __nfds, sizeof (*__fds),
 			  __glibc_objsize (__fds),
@@ -58,9 +63,13 @@ extern int __REDIRECT (__ppoll64_chk_warn, (struct pollfd *__fds, nfds_t __n,
 		       __ppoll64_chk)
   __warnattr ("ppoll called with fds buffer too small file nfds entries");
 
-__fortify_function __fortified_attr_access (__write_only__, 1, 2) int
-ppoll (struct pollfd *__fds, nfds_t __nfds, const struct timespec *__timeout,
-       const __sigset_t *__ss)
+__fortify_function __fortified_attr_access (__write_only__, 1, 2)
+__attribute_overloadable__ int
+ppoll (__fortify_clang_overload_arg (struct pollfd *, ,__fds), nfds_t __nfds,
+       const struct timespec *__timeout, const __sigset_t *__ss)
+     __fortify_clang_warning_only_if_bos_lt2 (__nfds, __fds, sizeof (*__fds),
+					      "ppoll called with fds buffer "
+					      "too small file nfds entries")
 {
   return __glibc_fortify (ppoll64, __nfds, sizeof (*__fds),
 			  __glibc_objsize (__fds),
@@ -81,9 +90,13 @@ extern int __REDIRECT (__ppoll_chk_warn, (struct pollfd *__fds, nfds_t __nfds,
 		       __ppoll_chk)
   __warnattr ("ppoll called with fds buffer too small file nfds entries");
 
-__fortify_function __fortified_attr_access (__write_only__, 1, 2) int
-ppoll (struct pollfd *__fds, nfds_t __nfds, const struct timespec *__timeout,
-       const __sigset_t *__ss)
+__fortify_function __fortified_attr_access (__write_only__, 1, 2)
+__attribute_overloadable__ int
+ppoll (__fortify_clang_overload_arg (struct pollfd *, ,__fds), nfds_t __nfds,
+       const struct timespec *__timeout, const __sigset_t *__ss)
+     __fortify_clang_warning_only_if_bos_lt2 (__nfds, __fds, sizeof (*__fds),
+					      "ppoll called with fds buffer "
+					      "too small file nfds entries")
 {
   return __glibc_fortify (ppoll, __nfds, sizeof (*__fds),
 			  __glibc_objsize (__fds),
diff --git a/socket/bits/socket2.h b/socket/bits/socket2.h
index a88cb64370..04780f320e 100644
--- a/socket/bits/socket2.h
+++ b/socket/bits/socket2.h
@@ -30,14 +30,20 @@ extern ssize_t __REDIRECT (__recv_chk_warn,
      __warnattr ("recv called with bigger length than size of destination "
 		 "buffer");
 
-__fortify_function ssize_t
-recv (int __fd, void *__buf, size_t __n, int __flags)
+__fortify_function __attribute_overloadable__ ssize_t
+recv (int __fd, __fortify_clang_overload_arg0 (void *, ,__buf), size_t __n,
+      int __flags)
+     __fortify_clang_warning_only_if_bos0_lt (__n, __buf,
+					      "recv called with bigger length than "
+					      "size of destination buffer")
 {
   size_t sz = __glibc_objsize0 (__buf);
   if (__glibc_safe_or_unknown_len (__n, sizeof (char), sz))
     return __recv_alias (__fd, __buf, __n, __flags);
+#if !__fortify_use_clang
   if (__glibc_unsafe_len (__n, sizeof (char), sz))
     return __recv_chk_warn (__fd, __buf, __n, sz, __flags);
+#endif
   return __recv_chk (__fd, __buf, __n, sz, __flags);
 }
 
@@ -57,15 +63,21 @@ extern ssize_t __REDIRECT (__recvfrom_chk_warn,
      __warnattr ("recvfrom called with bigger length than size of "
 		 "destination buffer");
 
-__fortify_function ssize_t
-recvfrom (int __fd, void *__restrict __buf, size_t __n, int __flags,
+__fortify_function __attribute_overloadable__ ssize_t
+recvfrom (int __fd, __fortify_clang_overload_arg0 (void *, __restrict, __buf),
+	  size_t __n, int __flags,
 	  __SOCKADDR_ARG __addr, socklen_t *__restrict __addr_len)
+     __fortify_clang_warning_only_if_bos0_lt (__n, __buf,
+					      "recvfrom called with bigger length "
+					      "than size of destination buffer")
 {
   size_t sz = __glibc_objsize0 (__buf);
   if (__glibc_safe_or_unknown_len (__n, sizeof (char), sz))
     return __recvfrom_alias (__fd, __buf, __n, __flags, __addr, __addr_len);
+#if !__fortify_use_clang
   if (__glibc_unsafe_len (__n, sizeof (char), sz))
     return __recvfrom_chk_warn (__fd, __buf, __n, sz, __flags, __addr,
 				__addr_len);
+#endif
   return __recvfrom_chk (__fd, __buf, __n, sz, __flags, __addr, __addr_len);
 }
-- 
2.34.1