Blob Blame Raw
Short description: Work ld.so --verify crash on debuginfo files.
Author(s): Fedora glibc team <glibc@lists.fedoraproject.org>
Origin: PATCH
Bug-RHEL: #741105, #767146
Upstream status: not-needed

This change is designed to work around running ld.so on a debuginfo
file. This is the wrong fix for this problem and should be dropped.
The correct solution is to mark debuginfo files as new types of
ELF files.

Index: glibc-2.22-386-g95e8397/elf/dl-load.c
===================================================================
--- glibc-2.22-386-g95e8397.orig/elf/dl-load.c
+++ glibc-2.22-386-g95e8397/elf/dl-load.c
@@ -881,7 +881,8 @@ _dl_map_object_from_fd (const char *name
 
   /* Get file information.  */
   struct r_file_id id;
-  if (__glibc_unlikely (!_dl_get_file_id (fd, &id)))
+  struct stat64 st;
+  if (__glibc_unlikely (!_dl_get_file_id (fd, &id, &st)))
     {
       errstring = N_("cannot stat shared object");
     call_lose_errno:
@@ -1076,6 +1077,16 @@ _dl_map_object_from_fd (const char *name
 		= N_("ELF load command address/offset not properly aligned");
 	      goto call_lose;
 	    }
+	  if (__glibc_unlikely (ph->p_offset + ph->p_filesz > st.st_size))
+	    {
+	      /* If the segment requires zeroing of part of its last
+		 page, we'll crash when accessing the unmapped page.
+		 There's still a possibility of a race, if the shared
+		 object is truncated between the fxstat above and the
+		 memset below.  */
+	      errstring = N_("ELF load command past end of file");
+	      goto call_lose;
+	    }
 
 	  struct loadcmd *c = &loadcmds[nloadcmds++];
 	  c->mapstart = ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize));
Index: glibc-2.22-386-g95e8397/sysdeps/generic/dl-fileid.h
===================================================================
--- glibc-2.22-386-g95e8397.orig/sysdeps/generic/dl-fileid.h
+++ glibc-2.22-386-g95e8397/sysdeps/generic/dl-fileid.h
@@ -29,7 +29,8 @@ struct r_file_id
    On error, returns false, with errno set.  */
 static inline bool
 _dl_get_file_id (int fd __attribute__ ((unused)),
-		 struct r_file_id *id __attribute__ ((unused)))
+		 struct r_file_id *id __attribute__ ((unused)),
+		 struct stat64_t *st __attribute__((unused)))
 {
   return true;
 }
Index: glibc-2.22-386-g95e8397/sysdeps/posix/dl-fileid.h
===================================================================
--- glibc-2.22-386-g95e8397.orig/sysdeps/posix/dl-fileid.h
+++ glibc-2.22-386-g95e8397/sysdeps/posix/dl-fileid.h
@@ -27,18 +27,16 @@ struct r_file_id
     ino64_t ino;
   };
 
-/* Sample FD to fill in *ID.  Returns true on success.
+/* Sample FD to fill in *ID and *ST.  Returns true on success.
    On error, returns false, with errno set.  */
 static inline bool
-_dl_get_file_id (int fd, struct r_file_id *id)
+_dl_get_file_id (int fd, struct r_file_id *id, struct stat64 *st)
 {
-  struct stat64 st;
-
-  if (__glibc_unlikely (__fxstat64 (_STAT_VER, fd, &st) < 0))
+  if (__glibc_unlikely (__fxstat64 (_STAT_VER, fd, st) < 0))
     return false;
 
-  id->dev = st.st_dev;
-  id->ino = st.st_ino;
+  id->dev = st->st_dev;
+  id->ino = st->st_ino;
   return true;
 }