improve out-of-bounds checking with GCC 10 attribute access [BZ #25219]

Adds the access attribute newly introduced in GCC 10 to the subset of
function declarations that are already covered by _FORTIFY_SOURCE and
that don't have corresponding GCC built-in equivalents.

Reviewed-by: DJ Delorie <dj@redhat.com>

1 files changed, 35 insertions, 23 deletions

diff --git a/posix/bits/unistd.h b/posix/bits/unistd.h
index b8a8211..725a83e 100644
--- a/posix/bits/unistd.h
+++ b/posix/bits/unistd.h
@@ -21,9 +21,11 @@
 #endif
 
 extern ssize_t __read_chk (int __fd, void *__buf, size_t __nbytes,
-			   size_t __buflen) __wur;
+			   size_t __buflen)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT (__read_alias, (int __fd, void *__buf,
-					  size_t __nbytes), read) __wur;
+					  size_t __nbytes), read)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT (__read_chk_warn,
 			   (int __fd, void *__buf, size_t __nbytes,
 			    size_t __buflen), __read_chk)
@@ -46,15 +48,19 @@ read (int __fd, void *__buf, size_t __nbytes)
 
 #ifdef __USE_UNIX98
 extern ssize_t __pread_chk (int __fd, void *__buf, size_t __nbytes,
-			    __off_t __offset, size_t __bufsize) __wur;
+			    __off_t __offset, size_t __bufsize)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __pread64_chk (int __fd, void *__buf, size_t __nbytes,
-			      __off64_t __offset, size_t __bufsize) __wur;
+			      __off64_t __offset, size_t __bufsize)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT (__pread_alias,
 			   (int __fd, void *__buf, size_t __nbytes,
-			    __off_t __offset), pread) __wur;
+			    __off_t __offset), pread)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT (__pread64_alias,
 			   (int __fd, void *__buf, size_t __nbytes,
-			    __off64_t __offset), pread64) __wur;
+			    __off64_t __offset), pread64)
+  __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT (__pread_chk_warn,
 			   (int __fd, void *__buf, size_t __nbytes,
 			    __off_t __offset, size_t __bufsize), __pread_chk)
@@ -123,11 +129,11 @@ pread64 (int __fd, void *__buf, size_t __nbytes, __off64_t __offset)
 extern ssize_t __readlink_chk (const char *__restrict __path,
 			       char *__restrict __buf, size_t __len,
 			       size_t __buflen)
-     __THROW __nonnull ((1, 2)) __wur;
+     __THROW __nonnull ((1, 2)) __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT_NTH (__readlink_alias,
 			       (const char *__restrict __path,
 				char *__restrict __buf, size_t __len), readlink)
-     __nonnull ((1, 2)) __wur;
+     __nonnull ((1, 2)) __wur __attr_access ((__write_only__, 2, 3));
 extern ssize_t __REDIRECT_NTH (__readlink_chk_warn,
 			       (const char *__restrict __path,
 				char *__restrict __buf, size_t __len,
@@ -155,12 +161,12 @@ __NTH (readlink (const char *__restrict __path, char *__restrict __buf,
 extern ssize_t __readlinkat_chk (int __fd, const char *__restrict __path,
 				 char *__restrict __buf, size_t __len,
 				 size_t __buflen)
-     __THROW __nonnull ((2, 3)) __wur;
+     __THROW __nonnull ((2, 3)) __wur __attr_access ((__write_only__, 3, 4));
 extern ssize_t __REDIRECT_NTH (__readlinkat_alias,
 			       (int __fd, const char *__restrict __path,
 				char *__restrict __buf, size_t __len),
 			       readlinkat)
-     __nonnull ((2, 3)) __wur;
+     __nonnull ((2, 3)) __wur __attr_access ((__write_only__, 3, 4));
 extern ssize_t __REDIRECT_NTH (__readlinkat_chk_warn,
 			       (int __fd, const char *__restrict __path,
 				char *__restrict __buf, size_t __len,
@@ -187,9 +193,10 @@ __NTH (readlinkat (int __fd, const char *__restrict __path,
 #endif
 
 extern char *__getcwd_chk (char *__buf, size_t __size, size_t __buflen)
-     __THROW __wur;
+     __THROW __wur __attr_access ((__write_only__, 1, 2));
 extern char *__REDIRECT_NTH (__getcwd_alias,
-			     (char *__buf, size_t __size), getcwd) __wur;
+			     (char *__buf, size_t __size), getcwd)
+  __wur __attr_access ((__write_only__, 1, 2));
 extern char *__REDIRECT_NTH (__getcwd_chk_warn,
 			     (char *__buf, size_t __size, size_t __buflen),
 			     __getcwd_chk)
@@ -212,7 +219,7 @@ __NTH (getcwd (char *__buf, size_t __size))
 
 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 extern char *__getwd_chk (char *__buf, size_t buflen)
-     __THROW __nonnull ((1)) __wur;
+     __THROW __nonnull ((1)) __wur __attr_access ((__write_only__, 1, 2));
 extern char *__REDIRECT_NTH (__getwd_warn, (char *__buf), getwd)
      __nonnull ((1)) __wur __warnattr ("please use getcwd instead, as getwd "
 				       "doesn't specify buffer size");
@@ -227,9 +234,11 @@ __NTH (getwd (char *__buf))
 #endif
 
 extern size_t __confstr_chk (int __name, char *__buf, size_t __len,
-			     size_t __buflen) __THROW;
+			     size_t __buflen) __THROW
+  __attr_access ((__write_only__, 2, 3));
 extern size_t __REDIRECT_NTH (__confstr_alias, (int __name, char *__buf,
-						size_t __len), confstr);
+						size_t __len), confstr)
+   __attr_access ((__write_only__, 2, 3));
 extern size_t __REDIRECT_NTH (__confstr_chk_warn,
 			      (int __name, char *__buf, size_t __len,
 			       size_t __buflen), __confstr_chk)
@@ -252,9 +261,9 @@ __NTH (confstr (int __name, char *__buf, size_t __len))
 
 
 extern int __getgroups_chk (int __size, __gid_t __list[], size_t __listlen)
-     __THROW __wur;
+  __THROW __wur __attr_access ((__write_only__, 2, 1));
 extern int __REDIRECT_NTH (__getgroups_alias, (int __size, __gid_t __list[]),
-			   getgroups) __wur;
+			   getgroups) __wur __attr_access ((__write_only__, 2, 1));
 extern int __REDIRECT_NTH (__getgroups_chk_warn,
 			   (int __size, __gid_t __list[], size_t __listlen),
 			   __getgroups_chk)
@@ -277,7 +286,8 @@ __NTH (getgroups (int __size, __gid_t __list[]))
 
 
 extern int __ttyname_r_chk (int __fd, char *__buf, size_t __buflen,
-			    size_t __nreal) __THROW __nonnull ((2));
+			    size_t __nreal) __THROW __nonnull ((2))
+   __attr_access ((__write_only__, 2, 3));
 extern int __REDIRECT_NTH (__ttyname_r_alias, (int __fd, char *__buf,
 					       size_t __buflen), ttyname_r)
      __nonnull ((2));
@@ -304,7 +314,7 @@ __NTH (ttyname_r (int __fd, char *__buf, size_t __buflen))
 
 #ifdef __USE_POSIX199506
 extern int __getlogin_r_chk (char *__buf, size_t __buflen, size_t __nreal)
-     __nonnull ((1));
+     __nonnull ((1)) __attr_access ((__write_only__, 1, 2));
 extern int __REDIRECT (__getlogin_r_alias, (char *__buf, size_t __buflen),
 		       getlogin_r) __nonnull ((1));
 extern int __REDIRECT (__getlogin_r_chk_warn,
@@ -331,9 +341,10 @@ getlogin_r (char *__buf, size_t __buflen)
 
 #if defined __USE_MISC || defined __USE_UNIX98
 extern int __gethostname_chk (char *__buf, size_t __buflen, size_t __nreal)
-     __THROW __nonnull ((1));
+     __THROW __nonnull ((1)) __attr_access ((__write_only__, 1, 2));
 extern int __REDIRECT_NTH (__gethostname_alias, (char *__buf, size_t __buflen),
-			   gethostname) __nonnull ((1));
+			   gethostname)
+  __nonnull ((1)) __attr_access ((__write_only__, 1, 2));
 extern int __REDIRECT_NTH (__gethostname_chk_warn,
 			   (char *__buf, size_t __buflen, size_t __nreal),
 			   __gethostname_chk)
@@ -358,10 +369,11 @@ __NTH (gethostname (char *__buf, size_t __buflen))
 
 #if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_UNIX98)
 extern int __getdomainname_chk (char *__buf, size_t __buflen, size_t __nreal)
-     __THROW __nonnull ((1)) __wur;
+     __THROW __nonnull ((1)) __wur __attr_access ((__write_only__, 1, 2));
 extern int __REDIRECT_NTH (__getdomainname_alias, (char *__buf,
 						   size_t __buflen),
-			   getdomainname) __nonnull ((1)) __wur;
+			   getdomainname) __nonnull ((1))
+  __wur __attr_access ((__write_only__, 1, 2));
 extern int __REDIRECT_NTH (__getdomainname_chk_warn,
 			   (char *__buf, size_t __buflen, size_t __nreal),
 			   __getdomainname_chk)