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Check overflows in disked(8). 

Also ensure that an strtoimax(3) failure in parse_disk_quantity is handled.
This commit is contained in:
Nicholas De Nova 2017-03-12 17:30:45 -05:00
parent ef2e478607
commit 955406a3ed
1 changed files with 60 additions and 41 deletions
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101
disked/disked.c
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@ -594,17 +594,59 @@ bool rewrite_finish(struct rewrite* rewr)
return true;
}
// TODO: Finish this, add decimal support and protect against overflow.
static bool interactive;
static bool quitting;
static struct harddisk** hds;
static size_t hds_count;
static struct harddisk* current_hd;
static enum partition_table_type current_pt_type;
static struct partition_table* current_pt;
static size_t current_areas_count;
static struct device_area* current_areas;
static const char* fstab_path = "/etc/fstab";
__attribute__((format(printf, 1, 2)))
static void command_error(const char* format, ...)
{
va_list ap;
va_start(ap, format);
if ( !interactive )
verr(1, format, ap);
vfprintf(stderr, format, ap);
fprintf(stderr, ": %s\n", strerror(errno));
va_end(ap);
}
__attribute__((format(printf, 1, 2)))
static void command_errorx(const char* format, ...)
{
va_list ap;
va_start(ap, format);
if ( !interactive )
verrx(1, format, ap);
vfprintf(stderr, format, ap);
fprintf(stderr, "\n");
va_end(ap);
}
// TODO: Finish this and add decimal support.
static bool parse_disk_quantity(off_t* out, const char* string, off_t max)
{
if ( *string && isspace((unsigned char) *string) )
string++;
const char* end;
bool from_end = false;
errno = 0;
intmax_t value = strtoimax(string, (char**) &end, 10);
if ( value == INTMAX_MIN || errno )
{
if ( !errno )
errno = ERANGE;
command_error("Parsing `%s'", string);
return false;
}
if ( value < 0 )
{
// TODO: If the least possible value, overflow.
value = -value;
from_end = true;
}
@ -694,17 +736,6 @@ static bool parse_disk_quantity(off_t* out, const char* string, off_t max)
return *out = value, true;
}
static bool interactive;
static bool quitting;
static struct harddisk** hds;
static size_t hds_count;
static struct harddisk* current_hd;
static enum partition_table_type current_pt_type;
static struct partition_table* current_pt;
static size_t current_areas_count;
static struct device_area* current_areas;
static const char* fstab_path = "/etc/fstab";
static bool lookup_fstab_by_blockdevice(struct fstab* out_fsent,
char** out_storage,
struct blockdevice* bdev)
@ -850,30 +881,6 @@ static bool add_blockdevice_to_fstab(struct blockdevice* bdev,
return rewrite_finish(&rewr);
}
__attribute__((format(printf, 1, 2)))
static void command_error(const char* format, ...)
{
va_list ap;
va_start(ap, format);
if ( !interactive )
verr(1, format, ap);
vfprintf(stderr, format, ap);
fprintf(stderr, ": %s\n", strerror(errno));
va_end(ap);
}
__attribute__((format(printf, 1, 2)))
static void command_errorx(const char* format, ...)
{
va_list ap;
va_start(ap, format);
if ( !interactive )
verrx(1, format, ap);
vfprintf(stderr, format, ap);
fprintf(stderr, "\n");
va_end(ap);
}
static void unscan_partition(struct partition* p)
{
struct blockdevice* bdev = &p->bdev;
@ -951,8 +958,15 @@ static void scan_device(void)
// the partition table.
for ( size_t i = 0; i < current_pt->partitions_count; i++ )
scan_partition(current_pt->partitions[i]);
// TODO: Check for overflow here.
size_t areas_length = 2 * current_pt->partitions_count + 1;
size_t areas_length;
size_t partitions_count = current_pt->partitions_count;
if ( __builtin_mul_overflow(2, partitions_count, &areas_length) ||
__builtin_add_overflow(1, areas_length, &areas_length ) )
{
errno = EOVERFLOW;
command_error("Scanning `%s'", device_name(current_hd->path));
return;
}
if ( current_pt_type == PARTITION_TABLE_TYPE_MBR )
{
struct mbr_partition_table* mbrpt =
@ -2595,8 +2609,13 @@ static void on_rmtable(size_t argc, char** argv)
}
off_t sector_0 = 0; // MBR & GPT
off_t sector_1 = block_size; // GPT
// TODO: Overflow: Ensure underflow is not possible.
off_t sector_m1 = current_hd->st.st_size - block_size; // GPT
off_t sector_m1;
if ( __builtin_sub_overflow(current_hd->st.st_size, block_size, &sector_m1) )
{
errno = EOVERFLOW;
command_error("Removing partition table");
return;
}
if ( pwriteall(current_hd->fd, zeroes, block_size, sector_0) < block_size ||
pwriteall(current_hd->fd, zeroes, block_size, sector_1) < block_size ||
pwriteall(current_hd->fd, zeroes, block_size, sector_m1) < block_size )