On 4/23/20 10:20 PM, Peter Maydell wrote:
Calling g_mapped_file_unref() on a NULL pointer is not valid, and
glib will assert if you try it.
$ qemu-system-arm -M virt -display none -device loader,file=/tmp/bad.elf
qemu-system-arm: -device loader,file=/tmp/bad.elf: GLib: g_mapped_file_unref:
assertion 'file != NULL' failed
(One way to produce an ELF file that fails like this is to copy just
the first 16 bytes of a valid ELF file; this is sufficient to fool
the code in load_elf_ram_sym() into thinking it's an ELF file and
calling load_elf32() or load_elf64().)
The failure-exit path in load_elf can be reached from various points
in execution, and for some of those we haven't yet called
g_mapped_file_new_from_fd(). Add a condition to the unref call so we
only call it if we successfully created the GMappedFile to start with.
This will fix the assertion; for the specific case of the generic
loader it will then fall back from "guess this is an ELF file" to
"maybe it's a uImage or a hex file" and eventually to "just load as
a raw data file".
Reported-by: Randy Yates <ya...@ieee.org>
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
include/hw/elf_ops.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
index e0bb47bb678..398a4a2c85b 100644
--- a/include/hw/elf_ops.h
+++ b/include/hw/elf_ops.h
@@ -606,7 +606,9 @@ static int glue(load_elf, SZ)(const char *name, int fd,
*highaddr = (uint64_t)(elf_sword)high;
ret = total_size;
fail:
- g_mapped_file_unref(mapped_file);
+ if (mapped_file) {
+ g_mapped_file_unref(mapped_file);
+ }
g_free(phdr);
return ret;
}
