net/openssh/patches/0005-check-filenames-in-scp-client.patch

   1 From 125924e47db3713a85a70e0f8d6c23818d2ea054 Mon Sep 17 00:00:00 2001
   2 From: "djm@openbsd.org" <djm@openbsd.org>
   3 Date: Sat, 26 Jan 2019 22:41:28 +0000
   4 Subject: upstream: check in scp client that filenames sent during
   5
   6 remote->local directory copies satisfy the wildcard specified by the user.
   7
   8 This checking provides some protection against a malicious server
   9 sending unexpected filenames, but it comes at a risk of rejecting wanted
  10 files due to differences between client and server wildcard expansion rules.
  11
  12 For this reason, this also adds a new -T flag to disable the check.
  13
  14 reported by Harry Sintonen
  15 fix approach suggested by markus@;
  16 has been in snaps for ~1wk courtesy deraadt@
  17
  18 OpenBSD-Commit-ID: 00f44b50d2be8e321973f3c6d014260f8f7a8eda
  19
  20 CVE-2019-6111
  21
  22 Origin: backport, https://anongit.mindrot.org/openssh.git/commit/?id=391ffc4b9d31fa1f4ad566499fef9176ff8a07dc
  23 Last-Update: 2019-02-08
  24
  25 Patch-Name: check-filenames-in-scp-client.patch
  26 ---
  27  scp.1 | 12 +++++++++++-
  28  scp.c | 37 +++++++++++++++++++++++++++++--------
  29  2 files changed, 40 insertions(+), 9 deletions(-)
  30
  31 diff --git a/scp.1 b/scp.1
  32 index 0e5cc1b2d..397e77091 100644
  33 --- a/scp.1
  34 +++ b/scp.1
  35 @@ -18,7 +18,7 @@
  36  .Nd secure copy (remote file copy program)
  37  .Sh SYNOPSIS
  38  .Nm scp
  39 -.Op Fl 346BCpqrv
  40 +.Op Fl 346BCpqrTv
  41  .Op Fl c Ar cipher
  42  .Op Fl F Ar ssh_config
  43  .Op Fl i Ar identity_file
  44 @@ -208,6 +208,16 @@ to use for the encrypted connection.
  45  The program must understand
  46  .Xr ssh 1
  47  options.
  48 +.It Fl T
  49 +Disable strict filename checking.
  50 +By default when copying files from a remote host to a local directory
  51 +.Nm
  52 +checks that the received filenames match those requested on the command-line
  53 +to prevent the remote end from sending unexpected or unwanted files.
  54 +Because of differences in how various operating systems and shells interpret
  55 +filename wildcards, these checks may cause wanted files to be rejected.
  56 +This option disables these checks at the expense of fully trusting that
  57 +the server will not send unexpected filenames.
  58  .It Fl v
  59  Verbose mode.
  60  Causes
  61 diff --git a/scp.c b/scp.c
  62 index 1971c80cd..035037bcc 100644
  63 --- a/scp.c
  64 +++ b/scp.c
  65 @@ -94,6 +94,7 @@
  66  #include <dirent.h>
  67  #include <errno.h>
  68  #include <fcntl.h>
  69 +#include <fnmatch.h>
  70  #include <limits.h>
  71  #include <locale.h>
  72  #include <pwd.h>
  73 @@ -383,14 +384,14 @@ void verifydir(char *);
  74  struct passwd *pwd;
  75  uid_t userid;
  76  int errs, remin, remout;
  77 -int pflag, iamremote, iamrecursive, targetshouldbedirectory;
  78 +int Tflag, pflag, iamremote, iamrecursive, targetshouldbedirectory;
  79
  80  #define        CMDNEEDS        64
  81  char cmd[CMDNEEDS];            /* must hold "rcp -r -p -d\0" */
  82
  83  int response(void);
  84  void rsource(char *, struct stat *);
  85 -void sink(int, char *[]);
  86 +void sink(int, char *[], const char *);
  87  void source(int, char *[]);
  88  void tolocal(int, char *[]);
  89  void toremote(int, char *[]);
  90 @@ -429,8 +430,9 @@ main(int argc, char **argv)
  91         addargs(&args, "-oRemoteCommand=none");
  92         addargs(&args, "-oRequestTTY=no");
  93
  94 -       fflag = tflag = 0;
  95 -       while ((ch = getopt(argc, argv, "dfl:prtvBCc:i:P:q12346S:o:F:")) != -1)
  96 +       fflag = Tflag = tflag = 0;
  97 +       while ((ch = getopt(argc, argv,
  98 +           "dfl:prtTvBCc:i:P:q12346S:o:F:")) != -1) {
  99                 switch (ch) {
 100                 /* User-visible flags. */
 101                 case '1':
 102 @@ -509,9 +511,13 @@ main(int argc, char **argv)
 103                         setmode(0, O_BINARY);
 104  #endif
 105                         break;
 106 +               case 'T':
 107 +                       Tflag = 1;
 108 +                       break;
 109                 default:
 110                         usage();
 111                 }
 112 +       }
 113         argc -= optind;
 114         argv += optind;
 115
 116 @@ -542,7 +548,7 @@ main(int argc, char **argv)
 117         }
 118         if (tflag) {
 119                 /* Receive data. */
 120 -               sink(argc, argv);
 121 +               sink(argc, argv, NULL);
 122                 exit(errs != 0);
 123         }
 124         if (argc < 2)
 125 @@ -800,7 +806,7 @@ tolocal(int argc, char **argv)
 126                         continue;
 127                 }
 128                 free(bp);
 129 -               sink(1, argv + argc - 1);
 130 +               sink(1, argv + argc - 1, src);
 131                 (void) close(remin);
 132                 remin = remout = -1;
 133         }
 134 @@ -976,7 +982,7 @@ rsource(char *name, struct stat *statp)
 135          (sizeof(type) != 4 && sizeof(type) != 8))
 136
 137  void
 138 -sink(int argc, char **argv)
 139 +sink(int argc, char **argv, const char *src)
 140  {
 141         static BUF buffer;
 142         struct stat stb;
 143 @@ -992,6 +998,7 @@ sink(int argc, char **argv)
 144         unsigned long long ull;
 145         int setimes, targisdir, wrerrno = 0;
 146         char ch, *cp, *np, *targ, *why, *vect[1], buf[2048], visbuf[2048];
 147 +       char *src_copy = NULL, *restrict_pattern = NULL;
 148         struct timeval tv[2];
 149
 150  #define        atime   tv[0]
 151 @@ -1016,6 +1023,17 @@ sink(int argc, char **argv)
 152         (void) atomicio(vwrite, remout, "", 1);
 153         if (stat(targ, &stb) == 0 && S_ISDIR(stb.st_mode))
 154                 targisdir = 1;
 155 +       if (src != NULL && !iamrecursive && !Tflag) {
 156 +               /*
 157 +                * Prepare to try to restrict incoming filenames to match
 158 +                * the requested destination file glob.
 159 +                */
 160 +               if ((src_copy = strdup(src)) == NULL)
 161 +                       fatal("strdup failed");
 162 +               if ((restrict_pattern = strrchr(src_copy, '/')) != NULL) {
 163 +                       *restrict_pattern++ = '\0';
 164 +               }
 165 +       }
 166         for (first = 1;; first = 0) {
 167                 cp = buf;
 168                 if (atomicio(read, remin, cp, 1) != 1)
 169 @@ -1120,6 +1138,9 @@ sink(int argc, char **argv)
 170                         run_err("error: unexpected filename: %s", cp);
 171                         exit(1);
 172                 }
 173 +               if (restrict_pattern != NULL &&
 174 +                   fnmatch(restrict_pattern, cp, 0) != 0)
 175 +                       SCREWUP("filename does not match request");
 176                 if (targisdir) {
 177                         static char *namebuf;
 178                         static size_t cursize;
 179 @@ -1157,7 +1178,7 @@ sink(int argc, char **argv)
 180                                         goto bad;
 181                         }
 182                         vect[0] = xstrdup(np);
 183 -                       sink(1, vect);
 184 +                       sink(1, vect, src);
 185                         if (setimes) {
 186                                 setimes = 0;
 187                                 if (utimes(vect[0], tv) < 0)