Lots of the following warnings fixed, where all originated to self_pte()
that can return NULL.
libfdisk/src/dos.c:1850:25: warning: potential null pointer dereference
[-Wnull-dereference]
struct dos_partition *p = pe->pt_entry;
Signed-off-by: Sami Kerola <kerolasa@xxxxxx>
---
libfdisk/src/dos.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 55 insertions(+), 6 deletions(-)
diff --git a/libfdisk/src/dos.c b/libfdisk/src/dos.c
index 11946b38c..8b9ff464c 100644
--- a/libfdisk/src/dos.c
+++ b/libfdisk/src/dos.c
@@ -311,6 +311,8 @@ static void dos_init(struct fdisk_context *cxt)
for (i = 0; i < 4; i++) {
struct pte *pe = self_pte(cxt, i);
+ if (pe == NULL)
+ return;
pe->pt_entry = mbr_get_partition(cxt->firstsector, i);
pe->ex_entry = NULL;
pe->offset = 0;
@@ -502,6 +504,8 @@ static void read_extended(struct fdisk_context *cxt, size_t ext)
l->ext_index = ext;
pex = self_pte(cxt, ext);
+ if (pex == NULL)
+ return;
pex->ex_entry = pex->pt_entry;
p = pex->pt_entry;
@@ -515,12 +519,16 @@ static void read_extended(struct fdisk_context *cxt, size_t ext)
while (IS_EXTENDED (p->sys_ind)) {
pe = self_pte(cxt, cxt->label->nparts_max);
+ if (pe == NULL)
+ return;
if (cxt->label->nparts_max >= MAXIMUM_PARTS) {
/* This is not a Linux restriction, but
this program uses arrays of size MAXIMUM_PARTS.
Do not try to `improve' this test. */
struct pte *pre = self_pte(cxt,
cxt->label->nparts_max - 1);
+ if (pre == NULL)
+ return;
fdisk_warnx(cxt,
_("Omitting partitions after #%zu. They will be deleted "
"if you save this partition table."),
@@ -596,6 +604,8 @@ static void read_extended(struct fdisk_context *cxt, size_t ext)
/* remove last empty EBR */
pe = self_pte(cxt, cxt->label->nparts_max - 1);
+ if (pe == NULL)
+ return;
if (is_cleared_partition(pe->ex_entry) &&
is_cleared_partition(pe->pt_entry)) {
DBG(LABEL, ul_debug("DOS: EBR[offset=%ju]: empty, remove", (uintmax_t) pe->offset));
@@ -610,6 +620,8 @@ static void read_extended(struct fdisk_context *cxt, size_t ext)
for (i = 4; i < cxt->label->nparts_max; i++) {
p = self_partition(cxt, i);
+ if (p == NULL)
+ continue;
if (!dos_partition_get_size(p) &&
(cxt->label->nparts_max > 5 || q->sys_ind)) {
fdisk_info(cxt, _("omitting empty partition (%zu)"), i+1);
@@ -798,6 +810,8 @@ static int dos_probe_label(struct fdisk_context *cxt)
for (i = 0; i < 4; i++) {
struct pte *pe = self_pte(cxt, i);
+ if (pe == NULL)
+ return -1;
if (is_used_partition(pe->pt_entry))
cxt->label->nparts_cur++;
@@ -884,6 +898,8 @@ static fdisk_sector_t get_unused_start(struct fdisk_context *cxt,
fdisk_sector_t lastplusoff;
struct pte *pe = self_pte(cxt, i);
+ if (pe == NULL)
+ return UINT64_MAX;
if (start == pe->offset)
start += cxt->first_lba;
lastplusoff = last[i] + ((part_n < 4) ? 0 : cxt->first_lba);
@@ -1007,6 +1023,8 @@ static fdisk_sector_t get_unused_last(struct fdisk_context *cxt, size_t n,
for (i = 0; i < cxt->label->nparts_max; i++) {
struct pte *pe = self_pte(cxt, i);
+ if (pe == NULL)
+ return 0;
if (start < pe->offset && limit >= pe->offset)
limit = pe->offset - 1;
if (start < first[i] && limit >= first[i])
@@ -1087,6 +1105,8 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
temp = start;
dflt = start = get_unused_start(cxt, n, start, first, last);
+ if (start == UINT64_MAX)
+ continue;
if (n >= 4 && pa && fdisk_partition_has_start(pa) && cxt->script
&& cxt->first_lba > 1
@@ -1133,6 +1153,8 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
/* The second (and another) EBR */
struct pte *pe = self_pte(cxt, n);
+ if (pe == NULL)
+ return -EINVAL;
pe->offset = start - cxt->first_lba;
if (pe->offset == l->ext_offset) { /* must be corrected */
pe->offset++;
@@ -1235,6 +1257,11 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
set_partition(cxt, n, 0, start, stop, sys, fdisk_partition_is_bootable(pa));
if (n > 4) {
struct pte *pe = self_pte(cxt, n);
+
+ if (pe == NULL) {
+ rc = 1;
+ goto done;
+ }
set_partition(cxt, n - 1, 1, pe->offset, stop,
MBR_DOS_EXTENDED_PARTITION, 0);
}
@@ -1251,6 +1278,10 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
if (IS_EXTENDED(sys)) {
struct pte *pen = self_pte(cxt, n);
+ if (pen == NULL) {
+ rc = 1;
+ goto done;
+ }
l->ext_index = n;
l->ext_offset = start;
pen->ex_entry = p;
@@ -1278,6 +1309,8 @@ static int add_logical(struct fdisk_context *cxt,
DBG(LABEL, ul_debug("DOS: nparts max: %zu", cxt->label->nparts_max));
pe = self_pte(cxt, cxt->label->nparts_max);
+ if (pe == NULL)
+ return -1;
if (!pe->sectorbuffer) {
pe->sectorbuffer = calloc(1, cxt->sector_size);
if (!pe->sectorbuffer)
@@ -1476,6 +1509,8 @@ static int dos_verify_disklabel(struct fdisk_context *cxt)
total++;
p = self_partition(cxt, i);
+ if (p == NULL)
+ continue;
if (!p->sys_ind) {
if (i != 4 || i + 1 < cxt->label->nparts_max)
fdisk_warnx(cxt,
@@ -1759,7 +1794,8 @@ static int dos_write_disklabel(struct fdisk_context *cxt)
if (!mbr_changed) {
for (i = 0; i < 4; i++) {
struct pte *pe = self_pte(cxt, i);
- if (pe->changed)
+
+ if (pe && pe->changed)
mbr_changed = 1;
}
}
@@ -1788,7 +1824,7 @@ static int dos_write_disklabel(struct fdisk_context *cxt)
for (i = 4; i < cxt->label->nparts_max; i++) {
struct pte *pe = self_pte(cxt, i);
- if (!pe->changed || !pe->offset || !pe->sectorbuffer)
+ if (!pe || !pe->changed || !pe->offset || !pe->sectorbuffer)
continue;
mbr_set_magic(pe->sectorbuffer);
@@ -1847,7 +1883,7 @@ static int wrong_p_order(struct fdisk_context *cxt, size_t *prev)
for (i = 0 ; i < cxt->label->nparts_max; i++) {
struct pte *pe = self_pte(cxt, i);
- struct dos_partition *p = pe->pt_entry;
+ struct dos_partition *p = pe ? pe->pt_entry : NULL;
if (i == 4) {
last_i = 4;
@@ -1913,6 +1949,8 @@ static int dos_get_partition(struct fdisk_context *cxt, size_t n,
lb = self_label(cxt);
pe = self_pte(cxt, n);
+ if (pe == NULL)
+ return -EINVAL;
p = pe->pt_entry;
pa->used = !is_cleared_partition(p);
if (!pa->used)
@@ -2058,6 +2096,8 @@ static void print_chain_of_logicals(struct fdisk_context *cxt)
for (i = 4; i < cxt->label->nparts_max; i++) {
struct pte *pe = self_pte(cxt, i);
+ if (pe == NULL)
+ return;
fprintf(stderr, "#%02zu EBR [%10ju], "
"data[start=%10ju (%10ju), size=%10ju], "
"link[start=%10ju (%10ju), size=%10ju]\n",
@@ -2140,9 +2180,12 @@ again:
for (i = 4; i < cxt->label->nparts_max - 1; i++) {
struct pte *cur = self_pte(cxt, i),
*nxt = self_pte(cxt, i + 1);
+ fdisk_sector_t noff, ooff;
- fdisk_sector_t noff = nxt->offset - l->ext_offset,
- ooff = dos_partition_get_start(cur->ex_entry);
+ if (cur == NULL || nxt == NULL)
+ continue;
+ noff = nxt->offset - l->ext_offset;
+ ooff = dos_partition_get_start(cur->ex_entry);
if (noff == ooff)
continue;
@@ -2182,6 +2225,8 @@ static int dos_reorder(struct fdisk_context *cxt)
struct dos_partition *pi, *pk, *pe, pbuf;
pei = self_pte(cxt, i);
pek = self_pte(cxt, k);
+ if (pei == NULL || pek == NULL)
+ return -1;
pe = pei->ex_entry;
pei->ex_entry = pek->ex_entry;
@@ -2218,6 +2263,10 @@ int fdisk_dos_move_begin(struct fdisk_context *cxt, size_t i)
assert(fdisk_is_label(cxt, DOS));
pe = self_pte(cxt, i);
+ if (pe == NULL) {
+ fdisk_warnx(cxt, _("Partition %zu: no pte_label."), i + 1);
+ return 0;
+ }
p = pe->pt_entry;
if (!is_used_partition(p) || IS_EXTENDED (p->sys_ind)) {
@@ -2236,7 +2285,7 @@ int fdisk_dos_move_begin(struct fdisk_context *cxt, size_t i)
for (x = 0; x < cxt->label->nparts_max; x++) {
unsigned int end;
struct pte *prev_pe = self_pte(cxt, x);
- struct dos_partition *prev_p = prev_pe->pt_entry;
+ struct dos_partition *prev_p = prev_pe ? prev_pe->pt_entry : NULL;
if (!prev_p)
continue;
--
2.12.0
--
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