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authorDamien Miller <djm@cvs.openbsd.org>2006-01-31 10:19:03 +0000
committerDamien Miller <djm@cvs.openbsd.org>2006-01-31 10:19:03 +0000
commit4642520f044beb240350338ee00862f58a91200b (patch)
treee9389c74fca3c0fe8187ec99fe239d1ecd6f61ca /usr.bin
parentefd59c8464a11bdf906696175b911ed746ad30e5 (diff)
fix local arbitrary command execution vulnerability on local/local and
remote/remote copies (CVE-2006-0225, bz #1094), patch by t8m AT centrum.cz, polished by dtucker@ and myself; ok markus@
Diffstat (limited to 'usr.bin')
-rw-r--r--usr.bin/ssh/misc.c45
-rw-r--r--usr.bin/ssh/misc.h8
-rw-r--r--usr.bin/ssh/scp.c132
-rw-r--r--usr.bin/ssh/sftp.c8
4 files changed, 139 insertions, 54 deletions
diff --git a/usr.bin/ssh/misc.c b/usr.bin/ssh/misc.c
index 5a990db232e..9ec397aee8a 100644
--- a/usr.bin/ssh/misc.c
+++ b/usr.bin/ssh/misc.c
@@ -24,7 +24,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: misc.c,v 1.41 2006/01/05 23:43:53 djm Exp $");
+RCSID("$OpenBSD: misc.c,v 1.42 2006/01/31 10:19:02 djm Exp $");
#include <net/if.h>
@@ -383,12 +383,15 @@ void
addargs(arglist *args, char *fmt, ...)
{
va_list ap;
- char buf[1024];
+ char *cp;
u_int nalloc;
+ int r;
va_start(ap, fmt);
- vsnprintf(buf, sizeof(buf), fmt, ap);
+ r = vasprintf(&cp, fmt, ap);
va_end(ap);
+ if (r == -1)
+ fatal("addargs: argument too long");
nalloc = args->nalloc;
if (args->list == NULL) {
@@ -399,10 +402,44 @@ addargs(arglist *args, char *fmt, ...)
args->list = xrealloc(args->list, nalloc * sizeof(char *));
args->nalloc = nalloc;
- args->list[args->num++] = xstrdup(buf);
+ args->list[args->num++] = cp;
args->list[args->num] = NULL;
}
+void
+replacearg(arglist *args, u_int which, char *fmt, ...)
+{
+ va_list ap;
+ char *cp;
+ int r;
+
+ va_start(ap, fmt);
+ r = vasprintf(&cp, fmt, ap);
+ va_end(ap);
+ if (r == -1)
+ fatal("replacearg: argument too long");
+
+ if (which >= args->num)
+ fatal("replacearg: tried to replace invalid arg %d >= %d",
+ which, args->num);
+ xfree(args->list[which]);
+ args->list[which] = cp;
+}
+
+void
+freeargs(arglist *args)
+{
+ u_int i;
+
+ if (args->list != NULL) {
+ for (i = 0; i < args->num; i++)
+ xfree(args->list[i]);
+ xfree(args->list);
+ args->nalloc = args->num = 0;
+ args->list = NULL;
+ }
+}
+
/*
* Expands tildes in the file name. Returns data allocated by xmalloc.
* Warning: this calls getpw*.
diff --git a/usr.bin/ssh/misc.h b/usr.bin/ssh/misc.h
index 41591068695..0a1a09a68ba 100644
--- a/usr.bin/ssh/misc.h
+++ b/usr.bin/ssh/misc.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.h,v 1.28 2005/12/08 18:34:11 reyk Exp $ */
+/* $OpenBSD: misc.h,v 1.29 2006/01/31 10:19:02 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -38,7 +38,11 @@ struct arglist {
u_int num;
u_int nalloc;
};
-void addargs(arglist *, char *, ...) __attribute__((format(printf, 2, 3)));
+void addargs(arglist *, char *, ...)
+ __attribute__((format(printf, 2, 3)));
+void replacearg(arglist *, u_int, char *, ...)
+ __attribute__((format(printf, 3, 4)));
+void freeargs(arglist *);
/* readpass.c */
diff --git a/usr.bin/ssh/scp.c b/usr.bin/ssh/scp.c
index 1b0424f3065..bacefe17708 100644
--- a/usr.bin/ssh/scp.c
+++ b/usr.bin/ssh/scp.c
@@ -71,7 +71,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: scp.c,v 1.128 2005/12/06 22:38:27 reyk Exp $");
+RCSID("$OpenBSD: scp.c,v 1.129 2006/01/31 10:19:02 djm Exp $");
#include "xmalloc.h"
#include "atomicio.h"
@@ -118,6 +118,48 @@ killchild(int signo)
exit(1);
}
+static int
+do_local_cmd(arglist *a)
+{
+ u_int i;
+ int status;
+ pid_t pid;
+
+ if (a->num == 0)
+ fatal("do_local_cmd: no arguments");
+
+ if (verbose_mode) {
+ fprintf(stderr, "Executing:");
+ for (i = 0; i < a->num; i++)
+ fprintf(stderr, " %s", a->list[i]);
+ fprintf(stderr, "\n");
+ }
+ if ((pid = fork()) == -1)
+ fatal("do_local_cmd: fork: %s", strerror(errno));
+
+ if (pid == 0) {
+ execvp(a->list[0], a->list);
+ perror(a->list[0]);
+ exit(1);
+ }
+
+ do_cmd_pid = pid;
+ signal(SIGTERM, killchild);
+ signal(SIGINT, killchild);
+ signal(SIGHUP, killchild);
+
+ while (waitpid(pid, &status, 0) == -1)
+ if (errno != EINTR)
+ fatal("do_local_cmd: waitpid: %s", strerror(errno));
+
+ do_cmd_pid = -1;
+
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+ return (-1);
+
+ return (0);
+}
+
/*
* This function executes the given command as the specified user on the
* given host. This returns < 0 if execution fails, and >= 0 otherwise. This
@@ -162,7 +204,7 @@ do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout, int argc)
close(pin[0]);
close(pout[1]);
- args.list[0] = ssh_program;
+ replacearg(&args, 0, "%s", ssh_program);
if (remuser != NULL)
addargs(&args, "-l%s", remuser);
addargs(&args, "%s", host);
@@ -225,8 +267,9 @@ main(int argc, char **argv)
/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
sanitise_stdfd();
+ memset(&args, '\0', sizeof(args));
args.list = NULL;
- addargs(&args, "ssh"); /* overwritten with ssh_program */
+ addargs(&args, "%s", ssh_program);
addargs(&args, "-x");
addargs(&args, "-oForwardAgent no");
addargs(&args, "-oPermitLocalCommand no");
@@ -363,6 +406,10 @@ toremote(char *targ, int argc, char **argv)
{
int i, len;
char *bp, *host, *src, *suser, *thost, *tuser, *arg;
+ arglist alist;
+
+ memset(&alist, '\0', sizeof(alist));
+ alist.list = NULL;
*targ++ = 0;
if (*targ == 0)
@@ -380,56 +427,48 @@ toremote(char *targ, int argc, char **argv)
tuser = NULL;
}
+ if (tuser != NULL && !okname(tuser)) {
+ xfree(arg);
+ return;
+ }
+
for (i = 0; i < argc - 1; i++) {
src = colon(argv[i]);
if (src) { /* remote to remote */
- static char *ssh_options =
- "-x -o'ClearAllForwardings yes'";
+ freeargs(&alist);
+ addargs(&alist, "%s", ssh_program);
+ if (verbose_mode)
+ addargs(&alist, "-v");
+ addargs(&alist, "-x");
+ addargs(&alist, "-oClearAllForwardings yes");
+ addargs(&alist, "-n");
+
*src++ = 0;
if (*src == 0)
src = ".";
host = strrchr(argv[i], '@');
- len = strlen(ssh_program) + strlen(argv[i]) +
- strlen(src) + (tuser ? strlen(tuser) : 0) +
- strlen(thost) + strlen(targ) +
- strlen(ssh_options) + CMDNEEDS + 20;
- bp = xmalloc(len);
+
if (host) {
*host++ = 0;
host = cleanhostname(host);
suser = argv[i];
if (*suser == '\0')
suser = pwd->pw_name;
- else if (!okname(suser)) {
- xfree(bp);
+ else if (!okname(suser))
continue;
- }
- if (tuser && !okname(tuser)) {
- xfree(bp);
- continue;
- }
- snprintf(bp, len,
- "%s%s %s -n "
- "-l %s %s %s %s '%s%s%s:%s'",
- ssh_program, verbose_mode ? " -v" : "",
- ssh_options, suser, host, cmd, src,
- tuser ? tuser : "", tuser ? "@" : "",
- thost, targ);
+ addargs(&alist, "-l");
+ addargs(&alist, "%s", suser);
} else {
host = cleanhostname(argv[i]);
- snprintf(bp, len,
- "exec %s%s %s -n %s "
- "%s %s '%s%s%s:%s'",
- ssh_program, verbose_mode ? " -v" : "",
- ssh_options, host, cmd, src,
- tuser ? tuser : "", tuser ? "@" : "",
- thost, targ);
}
- if (verbose_mode)
- fprintf(stderr, "Executing: %s\n", bp);
- if (system(bp) != 0)
+ addargs(&alist, "%s", host);
+ addargs(&alist, "%s", cmd);
+ addargs(&alist, "%s", src);
+ addargs(&alist, "%s%s%s:%s",
+ tuser ? tuser : "", tuser ? "@" : "",
+ thost, targ);
+ if (do_local_cmd(&alist) != 0)
errs = 1;
- (void) xfree(bp);
} else { /* local to remote */
if (remin == -1) {
len = strlen(targ) + CMDNEEDS + 20;
@@ -453,20 +492,23 @@ tolocal(int argc, char **argv)
{
int i, len;
char *bp, *host, *src, *suser;
+ arglist alist;
+
+ memset(&alist, '\0', sizeof(alist));
+ alist.list = NULL;
for (i = 0; i < argc - 1; i++) {
if (!(src = colon(argv[i]))) { /* Local to local. */
- len = strlen(_PATH_CP) + strlen(argv[i]) +
- strlen(argv[argc - 1]) + 20;
- bp = xmalloc(len);
- (void) snprintf(bp, len, "exec %s%s%s %s %s", _PATH_CP,
- iamrecursive ? " -r" : "", pflag ? " -p" : "",
- argv[i], argv[argc - 1]);
- if (verbose_mode)
- fprintf(stderr, "Executing: %s\n", bp);
- if (system(bp))
+ freeargs(&alist);
+ addargs(&alist, "%s", _PATH_CP);
+ if (iamrecursive)
+ addargs(&alist, "-r");
+ if (pflag)
+ addargs(&alist, "-p");
+ addargs(&alist, "%s", argv[i]);
+ addargs(&alist, "%s", argv[argc-1]);
+ if (do_local_cmd(&alist))
++errs;
- (void) xfree(bp);
continue;
}
*src++ = 0;
diff --git a/usr.bin/ssh/sftp.c b/usr.bin/ssh/sftp.c
index eb2b1941c97..52437f1f5be 100644
--- a/usr.bin/ssh/sftp.c
+++ b/usr.bin/ssh/sftp.c
@@ -16,7 +16,7 @@
#include "includes.h"
-RCSID("$OpenBSD: sftp.c,v 1.69 2005/12/06 22:38:27 reyk Exp $");
+RCSID("$OpenBSD: sftp.c,v 1.70 2006/01/31 10:19:02 djm Exp $");
#include <glob.h>
#include <histedit.h>
@@ -1433,8 +1433,9 @@ main(int argc, char **argv)
/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
sanitise_stdfd();
+ memset(&args, '\0', sizeof(args));
args.list = NULL;
- addargs(&args, "ssh"); /* overwritten with ssh_program */
+ addargs(&args, ssh_program);
addargs(&args, "-oForwardX11 no");
addargs(&args, "-oForwardAgent no");
addargs(&args, "-oPermitLocalCommand no");
@@ -1469,6 +1470,7 @@ main(int argc, char **argv)
break;
case 'S':
ssh_program = optarg;
+ replacearg(&args, 0, "%s", ssh_program);
break;
case 'b':
if (batchmode)
@@ -1545,7 +1547,6 @@ main(int argc, char **argv)
addargs(&args, "%s", host);
addargs(&args, "%s", (sftp_server != NULL ?
sftp_server : "sftp"));
- args.list[0] = ssh_program;
if (!batchmode)
fprintf(stderr, "Connecting to %s...\n", host);
@@ -1558,6 +1559,7 @@ main(int argc, char **argv)
fprintf(stderr, "Attaching to %s...\n", sftp_direct);
connect_to_server(sftp_direct, args.list, &in, &out);
}
+ freeargs(&args);
err = interactive_loop(in, out, file1, file2);