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Index: usr.bin/uudecode/uudecode.c
===================================================================
--- usr.bin/uudecode/uudecode.c
+++ usr.bin/uudecode/uudecode.c
@@ -47,6 +47,7 @@
* create the specified file, decoding as you go.
* used with uuencode.
*/
+#include <sys/capsicum.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
@@ -65,21 +66,71 @@
#include <string.h>
#include <unistd.h>
-static const char *infile, *outfile;
-static FILE *infp, *outfp;
-static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
+static const char *outfile;
+static FILE *outfp;
+static int base64, cflag, iflag, oflag, pflag, rflag, sflag, dirfd;
static void usage(void);
-static int decode(void);
-static int decode2(void);
-static int uu_decode(void);
-static int base64_decode(void);
+static int decode(FILE *infp, char *infile);
+static int decode2(FILE *infp, char *infile);
+static int uu_decode(FILE *infp, char *infile);
+static int base64_decode(FILE *infp, char *infile);
+
+static int
+safeoutfp(void)
+{
+ int flags, fd;
+ struct stat st;
+
+ flags = O_WRONLY | O_CREAT | O_EXCL;
+ if (lstat(outfile, &st) == 0) {
+ if (iflag) {
+ warnc(EEXIST, "%s", outfile);
+ return (0);
+ }
+ switch (st.st_mode & S_IFMT) {
+ case S_IFREG:
+ case S_IFLNK:
+ /* avoid symlink attacks */
+ if (unlink(outfile) == 0 || errno == ENOENT)
+ break;
+ warn("unlink %s", outfile);
+ return (1);
+ case S_IFDIR:
+ warnc(EISDIR, "%s", outfile);
+ return (1);
+ default:
+ if (oflag) {
+ /* trust command-line names */
+ flags &= ~O_EXCL;
+ break;
+ }
+ warnc(EEXIST, "%s", outfile);
+ return (1);
+ }
+ } else if (errno != ENOENT) {
+ warn("stat %s", outfile);
+ return (1);
+ }
+ if ((fd = open(outfile, flags, 0664)) < 0 ||
+ (outfp = fdopen(fd, "w")) == NULL) {
+ warn("open %s", outfile);
+ return (1);
+ }
+
+ return (0);
+}
int
main(int argc, char *argv[])
{
- int rval, ch;
-
+ int rval, ch, fnum, i;
+ FILE **infps;
+ char **infiles;
+
+ fnum = 0;
+ rval = 0;
+ outfp = NULL;
if (strcmp(basename(argv[0]), "b64decode") == 0)
base64 = 1;
@@ -102,6 +153,10 @@
oflag = 1; /* output to the specified file */
sflag = 1; /* do not strip pathnames for output */
outfile = optarg; /* set the output filename */
+ /* Precreate the output fd before sandboxing */
+ rval = safeoutfp();
+ if (rval != 0)
+ exit(rval);
break;
case 'p':
if (oflag)
@@ -126,27 +181,52 @@
argv += optind;
if (*argv != NULL) {
- rval = 0;
+ infps = malloc(sizeof(FILE*) * argc);
+ infiles = malloc(sizeof(char*) * argc);
+ if (infps == NULL || infiles == NULL)
+ errc(1, ENOMEM, "malloc() fds");
do {
- infp = fopen(infile = *argv, "r");
- if (infp == NULL) {
+ infps[fnum] = fopen(*argv, "r");
+ if (infps[fnum] == NULL) {
warn("%s", *argv);
rval = 1;
continue;
}
- rval |= decode();
- fclose(infp);
+ infiles[fnum] = *argv;
+ fnum++;
} while (*++argv);
} else {
- infile = "stdin";
- infp = stdin;
- rval = decode();
+ infps = malloc(sizeof(FILE*));
+ infiles = malloc(sizeof(char*));
+ if (infps == NULL || infiles == NULL)
+ errc(1, ENOMEM, "malloc() fd");
+ infps[fnum] = stdin;
+ infiles[fnum] = strdup("stdin");
+ if (infiles[fnum] == NULL)
+ errc(1, ENOMEM, "malloc()");
+ }
+
+ if ((dirfd = open(".", O_DIRECTORY)) < 0) {
+ warn("open(%s)", ".");
+ exit(1);
+ }
+
+ if (cap_enter() < 0 && errno != ENOSYS)
+ err(1, "failed to enter security sandbox");
+
+ for (i = 0; i < fnum; i++) {
+ rval |= decode(infps[i], infiles[i]);
+ fclose(infps[i]);
}
+
+ free(infps);
+ free(infiles);
+
exit(rval);
}
static int
-decode(void)
+decode(FILE *infp, char *infile)
{
int r, v;
@@ -155,17 +235,17 @@
outfile = "/dev/stdout";
outfp = stdout;
if (base64)
- return (base64_decode());
+ return (base64_decode(infp, infile));
else
- return (uu_decode());
+ return (uu_decode(infp, infile));
}
- v = decode2();
+ v = decode2(infp, infile);
if (v == EOF) {
warnx("%s: missing or bad \"begin\" line", infile);
return (1);
}
for (r = v; cflag; r |= v) {
- v = decode2();
+ v = decode2(infp, infile);
if (v == EOF)
break;
}
@@ -173,7 +253,7 @@
}
static int
-decode2(void)
+decode2(FILE *infp, char *infile)
{
int flags, fd, mode;
size_t n, m;
@@ -255,9 +335,13 @@
/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
if (pflag || strcmp(outfile, "/dev/stdout") == 0)
outfp = stdout;
- else {
+ else if (oflag && outfp != NULL) {
+ /* set mode of file created earlier */
+ if (fchmod(fileno(outfp), mode) != 0)
+ warn("%s: chmod %s", infile, outfile);
+ } else {
flags = O_WRONLY | O_CREAT | O_EXCL;
- if (lstat(outfile, &st) == 0) {
+ if (fstatat(dirfd, outfile, &st, AT_SYMLINK_NOFOLLOW) == 0) {
if (iflag) {
warnc(EEXIST, "%s: %s", infile, outfile);
return (0);
@@ -266,7 +350,8 @@
case S_IFREG:
case S_IFLNK:
/* avoid symlink attacks */
- if (unlink(outfile) == 0 || errno == ENOENT)
+ if (unlinkat(dirfd, outfile, 0) == 0 ||
+ errno == ENOENT)
break;
warn("%s: unlink %s", infile, outfile);
return (1);
@@ -283,24 +368,24 @@
return (1);
}
} else if (errno != ENOENT) {
- warn("%s: %s", infile, outfile);
+ warn("%s: stat %s", infile, outfile);
return (1);
}
- if ((fd = open(outfile, flags, mode)) < 0 ||
+ if ((fd = openat(dirfd, outfile, flags, mode)) < 0 ||
(outfp = fdopen(fd, "w")) == NULL) {
- warn("%s: %s", infile, outfile);
+ warn("%s: open %s", infile, outfile);
return (1);
}
}
if (base64)
- return (base64_decode());
+ return (base64_decode(infp, infile));
else
- return (uu_decode());
+ return (uu_decode(infp, infile));
}
static int
-get_line(char *buf, size_t size)
+get_line(FILE *infp, char *infile, char *buf, size_t size)
{
if (fgets(buf, size, infp) != NULL)
@@ -312,7 +397,7 @@
}
static int
-checkend(const char *ptr, const char *end, const char *msg)
+checkend(char *infile, const char *ptr, const char *end, const char *msg)
{
size_t n;
@@ -330,7 +415,7 @@
}
static int
-uu_decode(void)
+uu_decode(FILE *infp, char *infile)
{
int i, ch;
char *p;
@@ -338,7 +423,7 @@
/* for each input line */
for (;;) {
- switch (get_line(buf, sizeof(buf))) {
+ switch (get_line(infp, infile, buf, sizeof(buf))) {
case 0:
return (0);
case 1:
@@ -397,18 +482,18 @@
}
}
}
- switch (get_line(buf, sizeof(buf))) {
+ switch (get_line(infp, infile, buf, sizeof(buf))) {
case 0:
return (0);
case 1:
return (1);
default:
- return (checkend(buf, "end", "no \"end\" line"));
+ return (checkend(infile, buf, "end", "no \"end\" line"));
}
}
static int
-base64_decode(void)
+base64_decode(FILE *infp, char *infile)
{
int n, count, count4;
char inbuf[MAXPATHLEN + 1], *p;
@@ -418,7 +503,7 @@
leftover[0] = '\0';
for (;;) {
strcpy(inbuf, leftover);
- switch (get_line(inbuf + strlen(inbuf),
+ switch (get_line(infp, infile, inbuf + strlen(inbuf),
sizeof(inbuf) - strlen(inbuf))) {
case 0:
return (0);
@@ -450,7 +535,7 @@
break;
fwrite(outbuf, 1, n, outfp);
}
- return (checkend(inbuf, "====", "error decoding base64 input stream"));
+ return (checkend(infile, inbuf, "====", "error decoding base64 input stream"));
}
static void

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