[PATCH 2/5] __FD_ELT: Implement correct buffer overflow check

[KOSAKI Motohiro]

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
---
 ChangeLog                 |   14 ++++++++++++++
 bits/select.h             |    6 +++---
 debug/Versions            |    3 +++
 debug/fdelt_chk.c         |   11 +++++++++++
 misc/bits/select2.h       |   23 +++++++++++++----------
 misc/sys/select.h         |    2 +-
 sysdeps/x86/bits/select.h |    6 +++---
 7 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5311919..36bac6a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2013-04-13  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* misc/sys/select.h (__FD_ELT): Add fdset new argument.
+	* bits/select.h (__FD_SET, __FD_CLR, __FD_ISSET): Adapt
+	an above change.
+	* sysdeps/x86/bits/select.h (__FD_SET, __FD_CLR, __FD_ISSET):
+	Likewise.
+
+	* debug/fdelt_chk.c (__fdelt_buffer_chk): New.
+	* misc/bits/select2.h (__FD_ELT): Implement correct buffer
+	overflow check instead of hardcoded FD_SET_SIZE.
+
+	* debug/Versions: Added __fdelt_buffer_chk and __fdelt_buffer_warn.
+
 2013-03-25  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* debug/fdelt_chk.c (__fdelt_chk): Removed range check
diff --git a/bits/select.h b/bits/select.h
index ca87676..a10e18a 100644
--- a/bits/select.h
+++ b/bits/select.h
@@ -30,8 +30,8 @@
       __FDS_BITS (__arr)[__i] = 0;					      \
   } while (0)
 #define __FD_SET(d, s) \
-  ((void) (__FDS_BITS (s)[__FD_ELT(d)] |= __FD_MASK(d)))
+  ((void) (__FDS_BITS (s)[__FD_ELT(d, s)] |= __FD_MASK(d)))
 #define __FD_CLR(d, s) \
-  ((void) (__FDS_BITS (s)[__FD_ELT(d)] &= ~__FD_MASK(d)))
+  ((void) (__FDS_BITS (s)[__FD_ELT(d, s)] &= ~__FD_MASK(d)))
 #define __FD_ISSET(d, s) \
-  ((__FDS_BITS (s)[__FD_ELT (d)] & __FD_MASK (d)) != 0)
+  ((__FDS_BITS (s)[__FD_ELT (d, s)] & __FD_MASK (d)) != 0)
diff --git a/debug/Versions b/debug/Versions
index c1722fa..1ef2994 100644
--- a/debug/Versions
+++ b/debug/Versions
@@ -55,6 +55,9 @@ libc {
   GLIBC_2.16 {
     __poll_chk; __ppoll_chk;
   }
+  GLIBC_2.18 {
+    __fdelt_buffer_chk; __fdelt_buffer_warn;
+  }
   GLIBC_PRIVATE {
     __fortify_fail;
   }
diff --git a/debug/fdelt_chk.c b/debug/fdelt_chk.c
index 6588be0..8e16dc5 100644
--- a/debug/fdelt_chk.c
+++ b/debug/fdelt_chk.c
@@ -15,6 +15,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <sys/types.h>
 #include <sys/select.h>
 
 
@@ -25,3 +26,13 @@ __fdelt_nochk (long int d)
 }
 strong_alias (__fdelt_nochk, __fdelt_chk)
 strong_alias (__fdelt_nochk, __fdelt_warn)
+
+long int
+__fdelt_buffer_chk (long int fd, size_t buflen)
+{
+  if (fd / 8 >= buflen)
+    __chk_fail ();
+
+  return fd / __NFDBITS;;
+}
+strong_alias (__fdelt_buffer_chk, __fdelt_buffer_warn)
diff --git a/misc/bits/select2.h b/misc/bits/select2.h
index 03558c9..a0ffbb7 100644
--- a/misc/bits/select2.h
+++ b/misc/bits/select2.h
@@ -21,15 +21,18 @@
 #endif
 
 /* Helper functions to issue warnings and errors when needed.  */
-extern long int __fdelt_chk (long int __d);
-extern long int __fdelt_warn (long int __d)
+extern long int __fdelt_buffer_chk (long int __d, size_t buflen);
+extern long int __fdelt_buffer_warn (long int __d, size_t buflen)
   __warnattr ("bit outside of fd_set selected");
+
 #undef __FD_ELT
-#define	__FD_ELT(d) \
-  __extension__								    \
-  ({ long int __d = (d);						    \
-     (__builtin_constant_p (__d)					    \
-      ? (0 <= __d && __d < __FD_SETSIZE					    \
-	 ? (__d / __NFDBITS)						    \
-	 : __fdelt_warn (__d))						    \
-      : __fdelt_chk (__d)); })
+#define	__FD_ELT(d, s)							\
+  __extension__								\
+  ({									\
+    long int __d = (d);							\
+    (__bos0 (s) != (size_t) -1)						\
+      ? (__builtin_constant_p (__d) && ((__d / 8) >= __bos0 (s)))	\
+	? __fdelt_buffer_warn(__d, __bos0 (s))				\
+	: __fdelt_buffer_chk(__d, __bos0 (s))				\
+      : __d / __NFDBITS;						\
+  })
diff --git a/misc/sys/select.h b/misc/sys/select.h
index 21351fe..341190c 100644
--- a/misc/sys/select.h
+++ b/misc/sys/select.h
@@ -57,7 +57,7 @@ typedef long int __fd_mask;
 #undef	__NFDBITS
 /* It's easier to assume 8-bit bytes than to get CHAR_BIT.  */
 #define __NFDBITS	(8 * (int) sizeof (__fd_mask))
-#define	__FD_ELT(d)	((d) / __NFDBITS)
+#define	__FD_ELT(d, s)	((d) / __NFDBITS)
 #define	__FD_MASK(d)	((__fd_mask) 1 << ((d) % __NFDBITS))
 
 /* fd_set for select and pselect.  */
diff --git a/sysdeps/x86/bits/select.h b/sysdeps/x86/bits/select.h
index 8b87188..b29f301 100644
--- a/sysdeps/x86/bits/select.h
+++ b/sysdeps/x86/bits/select.h
@@ -56,8 +56,8 @@
 #endif	/* GNU CC */
 
 #define __FD_SET(d, set) \
-  ((void) (__FDS_BITS (set)[__FD_ELT (d)] |= __FD_MASK (d)))
+  ((void) (__FDS_BITS (set)[__FD_ELT (d, set)] |= __FD_MASK (d)))
 #define __FD_CLR(d, set) \
-  ((void) (__FDS_BITS (set)[__FD_ELT (d)] &= ~__FD_MASK (d)))
+  ((void) (__FDS_BITS (set)[__FD_ELT (d, set)] &= ~__FD_MASK (d)))
 #define __FD_ISSET(d, set) \
-  ((__FDS_BITS (set)[__FD_ELT (d)] & __FD_MASK (d)) != 0)
+  ((__FDS_BITS (set)[__FD_ELT (d, set)] & __FD_MASK (d)) != 0)
-- 
1.7.1