In grub_file_open the file handle returned by file filters has no file->name
set which leads to segmentation fault later referenced by grub_elf_file. We
move the file->name value assignment after file filters to make sure it will be
set and returned.
The stack backtrace for reference.
gdb --args ./grub-file --is-x86_64-xen-domu /boot/vmlinux-4.1.12-1-default.gz
(gdb) bt
#0 0x000000000047597e in grub_strlen (s=0x0) at ../grub-core/kern/misc.c:558
#1 0x00000000004757e2 in grub_strdup (s=0x0) at ../grub-core/kern/misc.c:463
#2 0x0000000000406418 in grub_elf_file (file=0x6dfb50, filename=0x0) at
../grub-core/kern/elf.c:89
#3 0x00000000004043b3 in grub_xen_file (file=0x6dfb50) at
../grub-core/loader/i386/xen_file.c:29
#4 0x0000000000403930 in grub_cmd_file (ctxt=0x7fffffffe120, argc=1,
args=0x6dfa00) at ../grub-core/commands/file.c:425
#5 0x000000000047e178 in grub_extcmd_dispatcher (cmd=0x6df730, argc=2,
args=0x6ddfb0, script=0x0) at ../grub-core/commands/extcmd.c:54
#6 0x000000000047e1d7 in grub_extcmd_dispatch (cmd=0x6df730, argc=2,
args=0x6ddfb0) at ../grub-core/commands/extcmd.c:67
#7 0x0000000000402945 in main (argc=3, argv=0x7fffffffe2e8) at
../util/grub-file.c:102
(gdb) frame 3
#3 0x00000000004043b3 in grub_xen_file (file=0x6dfb50) at
../grub-core/loader/i386/xen_file.c:29
29 elf = grub_elf_file (file, file->name);
---
grub-core/kern/file.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/grub-core/kern/file.c b/grub-core/kern/file.c
index 668f893..44047d7 100644
--- a/grub-core/kern/file.c
+++ b/grub-core/kern/file.c
@@ -111,9 +111,6 @@ grub_file_open (const char *name)
if ((file->fs->open) (file, file_name) != GRUB_ERR_NONE)
goto fail;
- file->name = grub_strdup (name);
- grub_errno = GRUB_ERR_NONE;
-
for (filter = 0; file && filter < ARRAY_SIZE (grub_file_filters_enabled);
filter++)
if (grub_file_filters_enabled[filter])
@@ -123,7 +120,12 @@ grub_file_open (const char *name)
}
if (!file)
grub_file_close (last_file);
-
+ else
+ {
+ file->name = grub_strdup (name);
+ grub_errno = GRUB_ERR_NONE;
+ }
+
grub_memcpy (grub_file_filters_enabled, grub_file_filters_all,
sizeof (grub_file_filters_enabled));
--
2.6.2
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