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Flaws in the Empire protocol make redirections within execute next to

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impossible to implement correctly, and nested execute practically
useless (#116377).  Catch and refuse those:
(executing): New.
(doexecute, prompt): Set and clear it.
(redir_authorized): Reject if set.
(doexecute, play): Don't signal doexecute() failure through input_fd,
because that screws up up when we're executing already.  Increment
send_eof in doexecute() instead.
(send_eof): External linkage.
This commit is contained in:
Markus Armbruster 2007-11-28 07:10:27 +00:00
parent 51846ec38f
commit 2dbc45eff7
3 changed files with 23 additions and 13 deletions
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22
src/client/servcmd.c
View file

@ -51,6 +51,7 @@ FILE *auxfp;
static FILE *redir_fp;
static FILE *pipe_fp;
static int executing;
static size_t input_to_forget;
static void prompt(int, char *, char *);
@ -126,6 +127,7 @@ prompt(int code, char *prompt, char *teles)
(void)pclose(pipe_fp);
pipe_fp = NULL;
}
executing = 0;
if (input_to_forget) {
forget_input(input_to_forget);
input_to_forget = 0;
@ -157,6 +159,11 @@ redir_authorized(char *arg, char *attempt)
{
size_t seen = seen_input(arg);
if (executing) {
fprintf(stderr, "Can't %s in a script\n", attempt);
return 0;
}
if (!seen || (input_to_forget && input_to_forget != seen)) {
fprintf(stderr, "WARNING! Server attempted to %s %s\n",
attempt, arg);
@ -217,7 +224,7 @@ doredir(char *p)
static void
dopipe(char *p)
{
if (!redir_authorized(p, "pipe to command"))
if (!redir_authorized(p, "pipe to shell command"))
return;
if (*p++ != '|') {
fprintf(stderr, "WARNING! Weird pipe %s", p);
@ -239,22 +246,29 @@ dopipe(char *p)
static void
doexecute(char *p)
{
input_fd = -1; /* make sure play() terminates exec */
int fd;
if (!redir_authorized(p, "read file"))
if (!redir_authorized(p, "execute script file")) {
send_eof++;
return;
}
p = fname(p);
if (*p == 0) {
fprintf(stderr, "Need a file to execute\n");
send_eof++;
return;
}
if ((input_fd = open(p, O_RDONLY)) < 0) {
if ((fd = open(p, O_RDONLY)) < 0) {
fprintf(stderr, "Can't open execute file %s: %s\n",
p, strerror(errno));
send_eof++;
return;
}
input_fd = fd;
executing = 1;
}
void