diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2018-03-14 17:46:38 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-03-21 15:13:25 +0100 |
| commit | b17a9054a0652a1481be48a6729e972abf02412f (patch) | |
| tree | e133947847afce6366b2ee2ede1059e08161b6f8 /hw/i386 | |
| parent | f1a63fcfcd92c88be8942b5ae71aef9749a4f135 (diff) | |
| download | qemu-b17a9054a0652a1481be48a6729e972abf02412f.zip | |
multiboot: Reject kernels exceeding the address space
The code path where mh_load_end_addr is non-zero in the Multiboot
header checks that mh_load_end_addr >= mh_load_addr and so
mb_load_size is checked. However, mb_load_size is not checked when
calculated from the file size, when mh_load_end_addr is 0.
If the kernel binary size is larger than can fit in the address space
after load_addr, we ended up with a kernel_size that is smaller than
load_size, which means that we read the file into a too small buffer.
Add a check to reject kernel files with such Multiboot headers.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jack Schwartz <jack.schwartz@oracle.com>
Diffstat (limited to 'hw/i386')
| -rw-r--r-- | hw/i386/multiboot.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c index b9064264d8..1e215bf8d3 100644 --- a/hw/i386/multiboot.c +++ b/hw/i386/multiboot.c @@ -247,6 +247,10 @@ int load_multiboot(FWCfgState *fw_cfg, } mb_load_size = kernel_file_size - mb_kernel_text_offset; } + if (mb_load_size > UINT32_MAX - mh_load_addr) { + error_report("kernel does not fit in address space"); + exit(1); + } if (mh_bss_end_addr) { if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) { error_report("invalid bss_end_addr address"); |