Add pread() and pwrite() checks

1 files changed, 34 insertions, 0 deletions

diff --git a/include/unistd.h b/include/unistd.h
index 4f0439b..205e31c 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -8,6 +8,36 @@
 
 #define __errordecl(name, msg) extern void name(void) __attribute__((__error__(msg)))
 
+__errordecl(__pread_error, "pread: buffer overflow detected");
+static inline __attribute__ ((always_inline))
+ssize_t
+__fortify_pread(int fd, void *buf, size_t n, off_t offset)
+{
+        size_t bos = __builtin_object_size(buf, 0);
+
+        if (__builtin_constant_p(n) && n > bos)
+                __pread_error();
+
+        if (n > bos)
+                __builtin_trap();
+        return pread(fd, buf, n, offset);
+}
+
+__errordecl(__pwrite_error, "pwrite: buffer overflow detected");
+static inline __attribute__ ((always_inline))
+ssize_t
+__fortify_pwrite(int fd, void *buf, size_t n, off_t offset)
+{
+        size_t bos = __builtin_object_size(buf, 0);
+
+        if (__builtin_constant_p(n) && n > bos)
+                __pwrite_error();
+
+        if (n > bos)
+                __builtin_trap();
+        return pwrite(fd, buf, n, offset);
+}
+
 __errordecl(__read_error, "read: buffer overflow detected");
 static inline __attribute__ ((always_inline))
 ssize_t
@@ -38,6 +68,10 @@ __fortify_write(int fd, void *buf, size_t n)
         return write(fd, buf, n);
 }
 
+#undef pread
+#define pread(fd, buf, n, offset) __fortify_pread(fd, buf, n, offset)
+#undef pwrite
+#define pwrite(fd, buf, n, offset) __fortify_pwrite(fd, buf, n, offset)
 #undef read
 #define read(fd, buf, n) __fortify_read(fd, buf, n)
 #undef write