+-- On Thu, 21 Dec 2017, Jack Schwartz wrote --+ | The multiboot spec (https://www.gnu.org/software/grub/manual/multiboot/), | section 3.1.3, allows for bss_end_addr to be zero. | | A zero bss_end_addr signifies there is no .bss section. | | Suggested-by: Daniel Kiper <daniel.ki...@oracle.com> | Signed-off-by: Jack Schwartz <jack.schwa...@oracle.com> | Reviewed-by: Daniel Kiper <daniel.ki...@oracle.com> | --- | hw/i386/multiboot.c | 18 ++++++++++-------- | 1 file changed, 10 insertions(+), 8 deletions(-) | | diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c | index c7b70c9..ff2733d 100644 | --- a/hw/i386/multiboot.c | +++ b/hw/i386/multiboot.c | @@ -233,12 +233,6 @@ int load_multiboot(FWCfgState *fw_cfg, | mh_entry_addr = ldl_p(header+i+28); | | if (mh_load_end_addr) { | - if (mh_bss_end_addr < mh_load_addr) { | - fprintf(stderr, "invalid mh_bss_end_addr address\n"); | - exit(1); | - } | - mb_kernel_size = mh_bss_end_addr - mh_load_addr; | - | if (mh_load_end_addr < mh_load_addr) { | fprintf(stderr, "invalid mh_load_end_addr address\n"); | exit(1); | @@ -249,8 +243,16 @@ int load_multiboot(FWCfgState *fw_cfg, | fprintf(stderr, "invalid kernel_file_size\n"); | exit(1); | } | - mb_kernel_size = kernel_file_size - mb_kernel_text_offset; | - mb_load_size = mb_kernel_size; | + mb_load_size = kernel_file_size - mb_kernel_text_offset; | + } | + if (mh_bss_end_addr) { | + if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) { | + fprintf(stderr, "invalid mh_bss_end_addr address\n"); | + exit(1); | + } | + mb_kernel_size = mh_bss_end_addr - mh_load_addr; | + } else { | + mb_kernel_size = mb_load_size; | } | | /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.
Looks good. Reviewed-by: Prasad J Pandit <p...@fedoraproject.org> Thank you. -- Prasad J Pandit / Red Hat Product Security Team 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
