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slirp: tftp: Rework filename handling 

This changes the filename handling from a static buffer in tftp_session
for the client-provided name + prefix to a dynamically allocated buffer
that keeps the combined path in one place.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Jan Kiszka 2009-06-24 14:42:30 +02:00 committed by Anthony Liguori
parent 20c24bf24d
commit 9367964ae2
1 changed files with 16 additions and 22 deletions
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38
slirp/tftp.c
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@ -27,7 +27,7 @@
struct tftp_session { struct tftp_session {
int in_use; int in_use;
char filename[TFTP_FILENAME_MAX]; char *filename;
struct in_addr client_ip; struct in_addr client_ip;
u_int16_t client_port; u_int16_t client_port;
@ -47,6 +47,7 @@ static void tftp_session_update(struct tftp_session *spt)
static void tftp_session_terminate(struct tftp_session *spt) static void tftp_session_terminate(struct tftp_session *spt)
{ {
qemu_free(spt->filename);
spt->in_use = 0; spt->in_use = 0;
} }
@ -62,8 +63,10 @@ static int tftp_session_allocate(struct tftp_t *tp)
goto found; goto found;
/* sessions time out after 5 inactive seconds */ /* sessions time out after 5 inactive seconds */
if ((int)(curtime - spt->timestamp) > 5000) if ((int)(curtime - spt->timestamp) > 5000) {
qemu_free(spt->filename);
goto found; goto found;
}
} }
return -1; return -1;
@ -103,15 +106,8 @@ static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
{ {
int fd; int fd;
int bytes_read = 0; int bytes_read = 0;
char buffer[1024];
int n;
n = snprintf(buffer, sizeof(buffer), "%s/%s", fd = open(spt->filename, O_RDONLY | O_BINARY);
tftp_prefix, spt->filename);
if (n >= sizeof(buffer))
return -1;
fd = open(buffer, O_RDONLY | O_BINARY);
if (fd < 0) { if (fd < 0) {
return -1; return -1;
@ -274,6 +270,7 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
{ {
struct tftp_session *spt; struct tftp_session *spt;
int s, k; int s, k;
size_t prefix_len;
char *req_fname; char *req_fname;
s = tftp_session_allocate(tp); s = tftp_session_allocate(tp);
@ -294,8 +291,13 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
k = 0; k = 0;
pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp); pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
/* prepend tftp_prefix */
prefix_len = strlen(tftp_prefix);
spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 1);
memcpy(spt->filename, tftp_prefix, prefix_len);
/* get name */ /* get name */
req_fname = spt->filename; req_fname = spt->filename + prefix_len;
while (1) { while (1) {
if (k >= TFTP_FILENAME_MAX || k >= pktlen) { if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
@ -322,10 +324,8 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
k += 6; /* skipping octet */ k += 6; /* skipping octet */
/* do sanity checks on the filename */ /* do sanity checks on the filename */
if (req_fname[0] != '/' || req_fname[strlen(req_fname) - 1] == '/' ||
if ((spt->filename[0] != '/') strstr(req_fname, "/../")) {
|| (spt->filename[strlen((char *)spt->filename) - 1] == '/')
|| strstr((char *)spt->filename, "/../")) {
tftp_send_error(spt, 2, "Access violation", tp); tftp_send_error(spt, 2, "Access violation", tp);
return; return;
} }
@ -360,13 +360,7 @@ static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
struct stat stat_p; struct stat stat_p;
if (tsize == 0) { if (tsize == 0) {
char buffer[1024]; if (stat(spt->filename, &stat_p) == 0)
int len;
len = snprintf(buffer, sizeof(buffer), "%s/%s",
tftp_prefix, spt->filename);
if (stat(buffer, &stat_p) == 0)
tsize = stat_p.st_size; tsize = stat_p.st_size;
else { else {
tftp_send_error(spt, 1, "File not found", tp); tftp_send_error(spt, 1, "File not found", tp);