Create a Makefile; fix memory-overwrite bug when file_len > requested_len

3 files changed, 57 insertions, 11 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..a44be9f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,45 @@
+TEST     = teststore test_mmap ftrunctest
+SONAME   = libobjstore.so.0
+VERSION  = 0.0.1
+OBJSTORE = libobjstore.so libobjstore.a
+
+OSOBJ	 = objstore.o
+OSPICOBJ = $(patsubst %.o,%.pic.o,$(OSOBJ))
+
+CC	 = gcc
+CFLAGS	 = -O2 -g
+PICFLAGS = $(CFLAGS) -fPIC
+SOFLAGS	 = -shared
+
+AR	 = ar cq
+RANLIB	 = ranlib
+
+all: $(OBJSTORE) $(TEST)
+
+clean:
+	rm -f *.o *~ core $(OBJSTORE) $(TEST)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -o $@ -c $<
+
+%.pic.o: %.c
+	$(CC) $(PICFLAGS) -o $@ -c $<
+
+libobjstore.so: $(OSPICOBJ)
+	$(CC) $(SOFLAGS) -Wl,-soname,$(SONAME) -o libobjstore.so.$(VERSION) $(OSPICOBJ)
+	ln -sf libobjstore.so.$(VERSION) $(SONAME)
+	ln -sf libobjstore.so.$(VERSION) libobjstore.so
+
+libobjstore.a: $(OSOBJ)
+	rm -f libobjstore.a
+	$(AR) libobjstore.a $(OSOBJ)
+	$(RANLIB) libobjstore.a
+
+teststore: teststore.o libobjstore.a
+	$(CC) $(LDFLAGS) -o $@ $< libobjstore.a
+
+test_mmap: test_mmap.o
+	$(CC) $(LDFLAGS) -o $@ $<
+
+ftrunctest: ftrunctest.o
+	$(CC) $(LDFLAGS) -o $@ $<
diff --git a/arena.c b/arena.c
index d7d3c1b..10df925 100644
--- a/arena.c
+++ b/arena.c
@@ -105,7 +105,7 @@ static void objstore_sigsegv(int signal, siginfo_t *siginfo, void *ptr)
 {
   struct ObjStore *os = objstore_os_struct;
   void *page;
-  off_t offset;
+  uintptr_t npage, offset;
   char *pageinfo;
   struct flock lock;
   int old_errno = errno;
@@ -127,23 +127,24 @@ static void objstore_sigsegv(int signal, siginfo_t *siginfo, void *ptr)
 # endif /* __i386__ */
 #endif /* __linux__ */
 
+  page = (void *)((uintptr_t)siginfo->si_addr & ~(os->pagesize-1));
+  offset = (uintptr_t)page - (uintptr_t)os->arena;
+  npage = (offset >> os->pageshift);
+  pageinfo = os->pageinfo + npage;
+
   if ( signal != SIGSEGV || siginfo->si_code != SEGV_ACCERR ||
-       ((uintptr_t)siginfo->si_addr - (uintptr_t)os->arena) >= os->arena_len ) {
+       offset >= os->arena_len ) {
     struct sigaction dfl;
-
+    
     dfl.sa_handler = SIG_DFL;
     sigemptyset(&dfl.sa_mask);
     dfl.sa_flags = SA_ONESHOT;
     sigaction(SIGSEGV, &dfl, NULL);
-
+    
     errno = old_errno;
     return;			/* Re-take fault */
   }
-
-  page = (void *)((uintptr_t)siginfo->si_addr & ~(os->pagesize-1));
-  offset = (uintptr_t)page - (uintptr_t)os->arena;
-  pageinfo = os->pageinfo + (offset >> os->pageshift);
-
+  
   mprotect(page, os->pagesize, PROT_READ|PROT_WRITE);
 
   switch ( (enum page_status) *pageinfo ) {
@@ -350,7 +351,7 @@ void *objstore_init(char *main_file, char *log_file, size_t *arena_len)
   lock.l_len    = 0;
   while ( fcntl(os->main_fd, F_SETLKW, &lock) == -1 && errno == EINTR );
   file_len = lseek(os->main_fd, 0, SEEK_END);
-  if ( len == 0 ) {
+  if ( len < file_len ) {
     len = file_len;
   }
   len = (len + os->pagesize - 1) & ~(os->pagesize - 1);
diff --git a/system.h b/system.h
index 9d74409..4a3e5c1 100644
--- a/system.h
+++ b/system.h
@@ -23,7 +23,7 @@
 /* These constants are appropriate for Linux/i386 */
 
 /* This is where we map the database file - must be constant */
-#define ARENA_ADDRESS	((void *)0x60000000)
+#define ARENA_ADDRESS	((void *)0x60000000UL)
 
 #endif /* SYSTEM_H */