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Ignore mad MBR partitions which extend outside of medium size

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This commit is contained in:
Thomas Schmitt 2021-02-28 16:16:18 +01:00
parent 98aea0c18a
commit 7d248c46e1
1 changed files with 30 additions and 4 deletions
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34
libisofs/fs_image.c
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@ -3800,17 +3800,18 @@ void iso_get_hc_sh(uint8_t *matches, uint32_t iso_image_size,
}
static
int iso_analyze_mbr_ptable(IsoImage *image, int flag)
int iso_analyze_mbr_ptable(IsoImage *image, IsoDataSource *src, int flag)
{
int i, j, ret, cyl_align_mode, part_after_image = 0;
int i, j, ret, cyl_align_mode, part_after_image = 0, ignore_part;
uint32_t start_h, start_s, start_c, end_h, end_s, end_c, sph = 0, hpc = 0;
uint32_t start_lba, num_blocks, end_chs_lba, image_size, lba, cyl_size;
uint8_t *data, pstatus, ptype, *hc_sh = NULL;
uint8_t *data, pstatus, ptype, *hc_sh = NULL, *buf = NULL;
struct iso_imported_sys_area *sai;
/* Bitmap for finding head_per_cyl and sectors_per_head. */
LIBISO_ALLOC_MEM(hc_sh, uint8_t, 32 * 63);
memset(hc_sh, 0xff, 32 * 63);
LIBISO_ALLOC_MEM(buf, uint8_t, 2048);
sai = image->imported_sa_info;
image_size = sai->image_size;
@ -3833,6 +3834,30 @@ int iso_analyze_mbr_ptable(IsoImage *image, int flag)
num_blocks = iso_read_lsb(data + 12, 4);
if (num_blocks <= 0)
continue;
/* Check whether the partition fits into size of medium */
ignore_part= ((off_t) num_blocks + (off_t) start_lba - (off_t) 1 >
(off_t) 0xffffffff);
if (!ignore_part) {
ret= src->read_block(src, start_lba / 4, buf);
if (ret != 1)
ignore_part = 1;
}
if (!ignore_part) {
lba = (start_lba + num_blocks - 1) / 4;
/* make sure not to ignore because of incomplete last 2048 block */
if (lba > 0 && (off_t) lba * (off_t) 4 + (off_t) 3 !=
(off_t) (start_lba + num_blocks - 1))
lba--;
ret= src->read_block(src, lba, buf);
if (ret != 1)
ignore_part = 1;
}
if (ignore_part) {
iso_msg_submit(image->id, ISO_GENERAL_NOTE, 0,
"Ignored non-empty MBR partition outside of medium capacity");
continue;
}
if (sph > 0) {
if (end_s != sph)
sph = 0xffffffff;
@ -3902,6 +3927,7 @@ int iso_analyze_mbr_ptable(IsoImage *image, int flag)
sai->system_area_options |= (cyl_align_mode << 8);
ret = 1;
ex:
LIBISO_FREE_MEM(buf);
LIBISO_FREE_MEM(hc_sh);
return ret;
@ -4016,7 +4042,7 @@ int iso_analyze_mbr(IsoImage *image, IsoDataSource *src, int flag)
((unsigned char *) sad)[511] != 0xaa)
{ret = 0; goto ex;}
ret = iso_analyze_mbr_ptable(image, 0);
ret = iso_analyze_mbr_ptable(image, src, 0);
if (ret <= 0)
goto ex;