| Message ID | 20170907063256.7418-1-ppandit@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] multiboot: validate multiboot header address values | expand |
On 07/09/2017 08:32, P J P wrote: > From: Prasad J Pandit <pjp@fedoraproject.org> > > While loading kernel via multiboot-v1 image, (flags & 0x00010000) > indicates that multiboot header contains valid addresses to load > the kernel image. These addresses are used to compute kernel > size and kernel text offset in the OS image. Validate these > address values to avoid an OOB access issue. > > This is CVE-2017-14167. > > Reported-by: Thomas Garnier <thgarnie@google.com> > Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> > --- > hw/i386/multiboot.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > Update: add CVE-ID to the commit message. > > diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c > index 6001f4caa2..c7b70c91d5 100644 > --- a/hw/i386/multiboot.c > +++ b/hw/i386/multiboot.c > @@ -221,15 +221,34 @@ int load_multiboot(FWCfgState *fw_cfg, > uint32_t mh_header_addr = ldl_p(header+i+12); > uint32_t mh_load_end_addr = ldl_p(header+i+20); > uint32_t mh_bss_end_addr = ldl_p(header+i+24); > + > mh_load_addr = ldl_p(header+i+16); > + if (mh_header_addr < mh_load_addr) { > + fprintf(stderr, "invalid mh_load_addr address\n"); > + exit(1); > + } > + > uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr); > uint32_t mb_load_size = 0; > 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); > + } > mb_load_size = mh_load_end_addr - mh_load_addr; > } else { > + if (kernel_file_size < mb_kernel_text_offset) { > + 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; > } > Queued, thanks. Paolo
diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c index 6001f4caa2..c7b70c91d5 100644 --- a/hw/i386/multiboot.c +++ b/hw/i386/multiboot.c @@ -221,15 +221,34 @@ int load_multiboot(FWCfgState *fw_cfg, uint32_t mh_header_addr = ldl_p(header+i+12); uint32_t mh_load_end_addr = ldl_p(header+i+20); uint32_t mh_bss_end_addr = ldl_p(header+i+24); + mh_load_addr = ldl_p(header+i+16); + if (mh_header_addr < mh_load_addr) { + fprintf(stderr, "invalid mh_load_addr address\n"); + exit(1); + } + uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr); uint32_t mb_load_size = 0; 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); + } mb_load_size = mh_load_end_addr - mh_load_addr; } else { + if (kernel_file_size < mb_kernel_text_offset) { + 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; }