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authorMatthew Fortune <matthew.fortune@imgtec.com>2014-10-01 17:08:51 +0100
committerMatthew Fortune <matthew.fortune@imgtec.com>2014-10-31 22:19:23 +0000
commitd6f373d21b19565838cb9848c15b8070f2fe1305 (patch)
treeccbe085a65f298929ae132d09daf1786533a29d0
parent67c379871ed04c4494f3fb01b012504d6cf63f6e (diff)
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Add a hook to enable load-time inspection of program headers
This hook can be used to perform additional compatibility checks between shared libraries by inspecting custom program header information. * elf/dl-machine-reject-phdr.h: New file. * elf/dl-load.c: #include that. (open_verify): Call elf_machine_reject_phdr_p and ignore the file if that returned true.
-rw-r--r--ChangeLog7
-rw-r--r--elf/dl-load.c6
-rw-r--r--elf/dl-machine-reject-phdr.h34
3 files changed, 47 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index 2f7e6f62b5..fac4138f5b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-10-31 Matthew Fortune <matthew.fortune@imgtec.com>
+
+ * elf/dl-machine-reject-phdr.h: New file.
+ * elf/dl-load.c: #include that.
+ (open_verify): Call elf_machine_reject_phdr_p and ignore the file
+ if that returned true.
+
2014-10-31 Roland McGrath <roland@hack.frob.com>
[BZ #17496]
diff --git a/elf/dl-load.c b/elf/dl-load.c
index ce5b626b26..7a03ccfd2a 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -41,6 +41,7 @@
#include <dl-load.h>
#include <dl-map-segments.h>
#include <dl-unmap-segments.h>
+#include <dl-machine-reject-phdr.h>
#include <endian.h>
@@ -1683,6 +1684,11 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader,
}
}
+ if (__glibc_unlikely (elf_machine_reject_phdr_p
+ (phdr, ehdr->e_phnum, fbp->buf, fbp->len,
+ loader, fd)))
+ goto close_and_out;
+
/* Check .note.ABI-tag if present. */
for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph)
if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && ph->p_align >= 4)
diff --git a/elf/dl-machine-reject-phdr.h b/elf/dl-machine-reject-phdr.h
new file mode 100644
index 0000000000..d110a32023
--- /dev/null
+++ b/elf/dl-machine-reject-phdr.h
@@ -0,0 +1,34 @@
+/* Machine-dependent program header inspection for the ELF loader.
+ Copyright (C) 2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _DL_MACHINE_REJECT_PHDR_H
+#define _DL_MACHINE_REJECT_PHDR_H 1
+
+#include <stdbool.h>
+
+/* Return true iff ELF program headers are incompatible with the running
+ host. */
+static inline bool
+elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, uint_fast16_t phnum,
+ const char *buf, size_t len, struct link_map *map,
+ int fd)
+{
+ return false;
+}
+
+#endif /* dl-machine-reject-phdr.h */