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vfs_preopen: cap the queue length to the maximum number that fits into the digits space

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If we have a single digit we only replace up to '9', which also fits
into a single digit.

We operate on numbers from 0 to 9999999999999999999 independent of the
architecture.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
This commit is contained in:
Stefan Metzmacher 2021-06-18 18:29:31 +00:00
parent 1197c87c91
commit e51a2e6e4e
1 changed files with 40 additions and 10 deletions
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50
source3/modules/vfs_preopen.c
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@ -32,6 +32,9 @@ static int vfs_preopen_debug_level = DBGC_VFS;
#undef DBGC_CLASS
#define DBGC_CLASS vfs_preopen_debug_level
#define PREOPEN_MAX_DIGITS 19
#define PREOPEN_MAX_NUMBER (uint64_t)9999999999999999999ULL
struct preopen_state;
struct preopen_helper {
@ -53,9 +56,9 @@ struct preopen_state {
size_t number_start; /* start offset into "template_fname" */
int num_digits; /* How many digits is the number long? */
int fnum_sent; /* last fname sent to children */
uint64_t fnum_sent; /* last fname sent to children */
int fnum_queue_end; /* last fname to be sent, based on
uint64_t fnum_queue_end;/* last fname to be sent, based on
* last open call + preopen:queuelen
*/
@ -102,8 +105,8 @@ static void preopen_queue_run(struct preopen_state *state)
snprintf(state->template_fname + state->number_start,
state->num_digits + 1,
"%.*lu", state->num_digits,
(long unsigned int)(state->fnum_sent + 1));
"%.*llu", state->num_digits,
(long long unsigned int)(state->fnum_sent + 1));
*pdelimiter = delimiter;
to_write = talloc_get_size(state->template_fname);
@ -353,12 +356,12 @@ static struct preopen_state *preopen_state_get(vfs_handle_struct *handle)
return state;
}
static bool preopen_parse_fname(const char *fname, unsigned long *pnum,
static bool preopen_parse_fname(const char *fname, uint64_t *pnum,
size_t *pstart_idx, int *pnum_digits)
{
const char *p;
char *q = NULL;
unsigned long num;
unsigned long long num;
size_t start_idx = 0;
int num_digits = -1;
int error = 0;
@ -382,12 +385,12 @@ static bool preopen_parse_fname(const char *fname, unsigned long *pnum,
start_idx = (p - fname);
num = smb_strtoul(p, (char **)&q, 10, &error, SMB_STR_STANDARD);
num = smb_strtoull(p, (char **)&q, 10, &error, SMB_STR_STANDARD);
if (error != 0) {
return false;
}
if (num+1 < num) {
if (num >= PREOPEN_MAX_NUMBER) {
/* overflow */
return false;
}
@ -400,6 +403,31 @@ static bool preopen_parse_fname(const char *fname, unsigned long *pnum,
return true;
}
static uint64_t num_digits_max_value(int num_digits)
{
uint64_t num_max = 1;
int i;
if (num_digits < 1) {
return 0;
}
if (num_digits >= PREOPEN_MAX_DIGITS) {
return PREOPEN_MAX_NUMBER;
}
for (i = 0; i < num_digits; i++) {
num_max *= 10;
}
/*
* We actually want
* 9 instead of 10
* 99 instead of 100
* 999 instead of 1000
*/
return num_max - 1;
}
static int preopen_openat(struct vfs_handle_struct *handle,
const struct files_struct *dirfsp,
const struct smb_filename *smb_fname,
@ -410,7 +438,8 @@ static int preopen_openat(struct vfs_handle_struct *handle,
const char *dirname = dirfsp->fsp_name->base_name;
struct preopen_state *state;
int res;
unsigned long num;
uint64_t num;
uint64_t num_max;
NTSTATUS status;
char *new_template = NULL;
size_t new_start = 0;
@ -553,7 +582,8 @@ static int preopen_openat(struct vfs_handle_struct *handle,
state->fnum_sent = num;
}
state->fnum_queue_end = num + state->queue_max;
num_max = num_digits_max_value(state->num_digits);
state->fnum_queue_end = MIN(num_max, num + state->queue_max);
preopen_queue_run(state);