[PATCH] Require mmap handler for a.out executables
Files supported by fs/proc/base.c, i.e. /proc/<pid>/*, are not capable of
meeting the validity checks in ELF load_elf_*() handling because they have
no mmap handler which is required by ELF. In order to stop a.out
executables being used as part of an exploit attack against /proc-related
vulnerabilities, we make a.out executables depend on ->mmap() existing.
Signed-off-by: Eugene Teo <eteo@redhat.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index f312103..517e111 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -278,6 +278,13 @@
return -ENOEXEC;
}
+ /*
+ * Requires a mmap handler. This prevents people from using a.out
+ * as part of an exploit attack against /proc-related vulnerabilities.
+ */
+ if (!bprm->file->f_op || !bprm->file->f_op->mmap)
+ return -ENOEXEC;
+
fd_offset = N_TXTOFF(ex);
/* Check initial limits. This avoids letting people circumvent
@@ -476,6 +483,13 @@
goto out;
}
+ /*
+ * Requires a mmap handler. This prevents people from using a.out
+ * as part of an exploit attack against /proc-related vulnerabilities.
+ */
+ if (!file->f_op || !file->f_op->mmap)
+ goto out;
+
if (N_FLAGS(ex))
goto out;