diff options
Diffstat (limited to 'agent/findkey.c')
| -rw-r--r-- | agent/findkey.c | 283 |
1 files changed, 126 insertions, 157 deletions
diff --git a/agent/findkey.c b/agent/findkey.c index 6231484c6..2ad5044fe 100644 --- a/agent/findkey.c +++ b/agent/findkey.c @@ -27,10 +27,8 @@ #include <string.h> #include <ctype.h> #include <fcntl.h> -#include <assert.h> #include <unistd.h> #include <sys/stat.h> -#include <assert.h> #include <npth.h> /* (we use pth_sleep) */ #include "agent.h" @@ -42,6 +40,12 @@ #define O_BINARY 0 #endif + +static gpg_error_t read_key_file (const unsigned char *grip, + gcry_sexp_t *result, nvc_t *r_keymeta); +static gpg_error_t is_shadowed_key (gcry_sexp_t s_skey); + + /* Helper to pass data to the check callback of the unprotect function. */ struct try_unprotect_arg_s { @@ -53,15 +57,16 @@ struct try_unprotect_arg_s }; -/* Return the file name for the 20 byte keygrip GRIP. Return NULL on - * error. */ +/* Return the file name for the 20 byte keygrip GRIP. With FOR_NEW + * create a file name for later renaming to the actual name. Return + * NULL on error. */ static char * -fname_from_keygrip (const unsigned char *grip) +fname_from_keygrip (const unsigned char *grip, int for_new) { - char hexgrip[40+4+1]; + char hexgrip[40+4+4+1]; bin2hex (grip, 20, hexgrip); - strcpy (hexgrip+40, ".key"); + strcpy (hexgrip+40, for_new? ".key.tmp" : ".key"); return make_filename_try (gnupg_homedir (), GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL); @@ -70,8 +75,8 @@ fname_from_keygrip (const unsigned char *grip) /* Write the S-expression formatted key (BUFFER,LENGTH) to our key * storage. With FORCE passed as true an existing key with the given - * GRIP will get overwritten. If SERIALNO and KEYREF are given a - * Token line is added to the key if the extended format is used. If + * GRIP will be overwritten. If SERIALNO and KEYREF are given a Token + * line is added to the key if the extended format is used. If * TIMESTAMP is not zero and the key doies not yet exists it will be * recorded as creation date. */ int @@ -82,115 +87,40 @@ agent_write_private_key (const unsigned char *grip, time_t timestamp) { gpg_error_t err; - char *fname; + char *oldfname = NULL; + char *fname = NULL; estream_t fp; - int update, newkey; + int newkey = 0; nvc_t pk = NULL; gcry_sexp_t key = NULL; + int is_regular; int remove = 0; char *token0 = NULL; char *token = NULL; char *dispserialno_buffer = NULL; char **tokenfields = NULL; + int blocksigs = 0; - fname = fname_from_keygrip (grip); - if (!fname) + oldfname = fname_from_keygrip (grip, 0); + if (!oldfname) return out_of_core (); - /* FIXME: Write to a temp file first so that write failures during - key updates won't lead to a key loss. */ - - if (!force && !gnupg_access (fname, F_OK)) - { - log_error ("secret key file '%s' already exists\n", fname); - xfree (fname); - return gpg_error (GPG_ERR_EEXIST); - } - - fp = es_fopen (fname, force? "rb+,mode=-rw" : "wbx,mode=-rw"); - if (!fp) - { - gpg_error_t tmperr = gpg_error_from_syserror (); - - if (force && gpg_err_code (tmperr) == GPG_ERR_ENOENT) - { - fp = es_fopen (fname, "wbx,mode=-rw"); - if (!fp) - tmperr = gpg_error_from_syserror (); - } - if (!fp) - { - log_error ("can't create '%s': %s\n", fname, gpg_strerror (tmperr)); - xfree (fname); - return tmperr; - } - update = 0; - newkey = 1; - } - else if (force) + err = read_key_file (grip, &key, &pk); + if (err) { - gpg_error_t rc; - char first; - - /* See if an existing key is in extended format. */ - if (es_fread (&first, 1, 1, fp) != 1) - { - rc = gpg_error_from_syserror (); - log_error ("error reading first byte from '%s': %s\n", - fname, strerror (errno)); - xfree (fname); - es_fclose (fp); - return rc; - } - - rc = es_fseek (fp, 0, SEEK_SET); - if (rc) - { - log_error ("error seeking in '%s': %s\n", fname, strerror (errno)); - xfree (fname); - es_fclose (fp); - return rc; - } - - if (first == '(') - { - /* Key is still in the old format - force it into extended - * format. We do not request an update here because an - * existing key is not yet in extended key format and no - * extended infos are yet available. */ - update = 0; - newkey = 0; - } + if (gpg_err_code (err) == GPG_ERR_ENOENT) + newkey = 1; else { - /* Key is already in the extended format. */ - update = 1; - newkey = 0; - } - } - else - { - /* The key file did not exist: we assume this is a new key and - * write the Created: entry. */ - update = 0; - newkey = 1; - } - - - if (update) - { - int lineno = 0; - - err = nvc_parse_private_key (&pk, &lineno, fp); - if (err && gpg_err_code (err) != GPG_ERR_ENOENT) - { - log_error ("error parsing '%s' line %d: %s\n", - fname, lineno, gpg_strerror (err)); + log_error ("can't open '%s': %s\n", oldfname, gpg_strerror (err)); goto leave; } } - else + + if (!pk) { + /* Key is still in the old format or does not exist - create a + * new container. */ pk = nvc_new_private_key (); if (!pk) { @@ -198,10 +128,13 @@ agent_write_private_key (const unsigned char *grip, goto leave; } } - es_clearerr (fp); + + /* Check whether we already have a regular key. */ + is_regular = (key && gpg_err_code (is_shadowed_key (key)) != GPG_ERR_TRUE); /* Turn (BUFFER,LENGTH) into a gcrypt s-expression and set it into * our name value container. */ + gcry_sexp_release (key); err = gcry_sexp_sscan (&key, NULL, buffer, length); if (err) goto leave; @@ -209,6 +142,22 @@ agent_write_private_key (const unsigned char *grip, if (err) goto leave; + /* Check that we do not update a regular key with a shadow key. */ + if (is_regular && gpg_err_code (is_shadowed_key (key)) == GPG_ERR_TRUE) + { + log_info ("updating regular key file '%s'" + " by a shadow key inhibited\n", oldfname); + err = 0; /* Simply ignore the error. */ + goto leave; + } + /* Check that we update a regular key only in force mode. */ + if (is_regular && !force) + { + log_error ("secret key file '%s' already exists\n", oldfname); + err = gpg_error (GPG_ERR_EEXIST); + goto leave; + } + /* If requested write a Token line. */ if (serialno && keyref) { @@ -283,10 +232,14 @@ agent_write_private_key (const unsigned char *grip, goto leave; } - /* Back to start and write. */ - err = es_fseek (fp, 0, SEEK_SET); - if (err) - goto leave; + /* Create a temporary file for writing. */ + fname = fname_from_keygrip (grip, 1); + fp = fname ? es_fopen (fname, "wbx,mode=-rw") : NULL; + if (!fp) + { + log_error ("can't create '%s': %s\n", fname, gpg_strerror (err)); + goto leave; + } err = nvc_write (pk, fp); if (!err) @@ -298,31 +251,34 @@ agent_write_private_key (const unsigned char *grip, goto leave; } - if (ftruncate (es_fileno (fp), es_ftello (fp))) + if (es_fclose (fp)) { err = gpg_error_from_syserror (); - log_error ("error truncating '%s': %s\n", fname, gpg_strerror (err)); + log_error ("error closing '%s': %s\n", fname, gpg_strerror (err)); remove = 1; goto leave; } + fp = NULL; - if (es_fclose (fp)) + err = gnupg_rename_file (fname, oldfname, &blocksigs); + if (err) { err = gpg_error_from_syserror (); - log_error ("error closing '%s': %s\n", fname, gpg_strerror (err)); + log_error ("error renaming '%s': %s\n", fname, gpg_strerror (err)); remove = 1; goto leave; } - else - fp = NULL; bump_key_eventcounter (); leave: + if (blocksigs) + gnupg_unblock_all_signals (); es_fclose (fp); - if (remove) + if (remove && fname) gnupg_remove (fname); xfree (fname); + xfree (oldfname); xfree (token); xfree (token0); xfree (dispserialno_buffer); @@ -345,7 +301,7 @@ try_unprotect_cb (struct pin_entry_info_s *pi) gnupg_isotime_t now, protected_at, tmptime; char *desc = NULL; - assert (!arg->unprotected_key); + log_assert (!arg->unprotected_key); arg->change_required = 0; err = agent_unprotect (ctrl, arg->protected_key, pi->pin, protected_at, @@ -722,7 +678,7 @@ unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text, } else { - assert (arg.unprotected_key); + log_assert (arg.unprotected_key); if (arg.change_required) { /* The callback told as that the user should change their @@ -730,7 +686,7 @@ unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text, size_t canlen, erroff; gcry_sexp_t s_skey; - assert (arg.unprotected_key); + log_assert (arg.unprotected_key); canlen = gcry_sexp_canon_len (arg.unprotected_key, 0, NULL, NULL); rc = gcry_sexp_sscan (&s_skey, &erroff, (char*)arg.unprotected_key, canlen); @@ -774,17 +730,17 @@ unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text, /* Read the key identified by GRIP from the private key directory and * return it as an gcrypt S-expression object in RESULT. If R_KEYMETA - * is not NULl and the extended key format is used, the meta data - * items are stored there. However the "Key:" item is removed from - * it. On failure returns an error code and stores NULL at RESULT. */ + * is not NULL, the meta data items are stored there. However the + * "Key:" item is removed. Returns an error code and stores NULL at + * RESULT. */ static gpg_error_t read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) { gpg_error_t err; char *fname; - estream_t fp; + estream_t fp = NULL; struct stat st; - unsigned char *buf; + unsigned char *buf = NULL; size_t buflen, erroff; gcry_sexp_t s_skey; char first; @@ -793,15 +749,19 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) if (r_keymeta) *r_keymeta = NULL; - fname = fname_from_keygrip (grip); - fp = fname? es_fopen (fname, "rb") : NULL; + fname = fname_from_keygrip (grip, 0); + if (!fname) + { + err = gpg_error_from_syserror (); + goto leave; + } + fp = es_fopen (fname, "rb"); if (!fp) { err = gpg_error_from_syserror (); if (gpg_err_code (err) != GPG_ERR_ENOENT) log_error ("can't open '%s': %s\n", fname, gpg_strerror (err)); - xfree (fname); - return err; + goto leave; } if (es_fread (&first, 1, 1, fp) != 1) @@ -809,18 +769,14 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) err = gpg_error_from_syserror (); log_error ("error reading first byte from '%s': %s\n", fname, gpg_strerror (err)); - xfree (fname); - es_fclose (fp); - return err; + goto leave; } if (es_fseek (fp, 0, SEEK_SET)) { err = gpg_error_from_syserror (); log_error ("error seeking in '%s': %s\n", fname, gpg_strerror (err)); - xfree (fname); - es_fclose (fp); - return err; + goto leave; } if (first != '(') @@ -830,8 +786,6 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) int line; err = nvc_parse_private_key (&pk, &line, fp); - es_fclose (fp); - if (err) log_error ("error parsing '%s' line %d: %s\n", fname, line, gpg_strerror (err)); @@ -849,17 +803,14 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) *r_keymeta = pk; else nvc_release (pk); - xfree (fname); - return err; + goto leave; } if (fstat (es_fileno (fp), &st)) { err = gpg_error_from_syserror (); log_error ("can't stat '%s': %s\n", fname, gpg_strerror (err)); - xfree (fname); - es_fclose (fp); - return err; + goto leave; } buflen = st.st_size; @@ -869,11 +820,7 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) err = gpg_error_from_syserror (); log_error ("error allocating %zu bytes for '%s': %s\n", buflen, fname, gpg_strerror (err)); - xfree (fname); - es_fclose (fp); - xfree (buf); - return err; - + goto leave; } if (es_fread (buf, buflen, 1, fp) != 1) @@ -881,25 +828,24 @@ read_key_file (const unsigned char *grip, gcry_sexp_t *result, nvc_t *r_keymeta) err = gpg_error_from_syserror (); log_error ("error reading %zu bytes from '%s': %s\n", buflen, fname, gpg_strerror (err)); - xfree (fname); - es_fclose (fp); - xfree (buf); - return err; + goto leave; } /* Convert the file into a gcrypt S-expression object. */ err = gcry_sexp_sscan (&s_skey, &erroff, (char*)buf, buflen); - xfree (fname); - es_fclose (fp); - xfree (buf); if (err) { log_error ("failed to build S-Exp (off=%u): %s\n", (unsigned int)erroff, gpg_strerror (err)); - return err; + goto leave; } *result = s_skey; - return 0; + + leave: + es_fclose (fp); + xfree (fname); + xfree (buf); + return err; } @@ -1270,6 +1216,29 @@ agent_is_eddsa_key (gcry_sexp_t s_key) } +/* This function returns GPG_ERR_TRUE if S_SKEY represents a shadowed + * key. 0 is return for other key types. Any other error may occur + * if S_SKEY is not valid. */ +static gpg_error_t +is_shadowed_key (gcry_sexp_t s_skey) +{ + gpg_error_t err; + unsigned char *buf; + size_t buflen; + + err = make_canon_sexp (s_skey, &buf, &buflen); + if (err) + return err; + + if (agent_private_key_type (buf) == PRIVATE_KEY_SHADOWED) + err = gpg_error (GPG_ERR_TRUE); + + wipememory (buf, buflen); + xfree (buf); + return err; +} + + /* Return the key for the keygrip GRIP. The result is stored at RESULT. This function extracts the key from the private key database and returns it as an S-expression object as it is. On @@ -1376,7 +1345,7 @@ agent_public_key_from_file (ctrl_t ctrl, such a task. After all that is what we do in protect.c. Need to find common patterns and write a straightformward API to use them. */ - assert (sizeof (size_t) <= sizeof (void*)); + log_assert (sizeof (size_t) <= sizeof (void*)); format = xtrymalloc (15+4+7*npkey+10+15+1+1); if (!format) @@ -1401,14 +1370,14 @@ agent_public_key_from_file (ctrl_t ctrl, *p++ = '('; *p++ = *s++; p = stpcpy (p, " %m)"); - assert (argidx < DIM (args)); + log_assert (argidx < DIM (args)); args[argidx++] = &array[idx]; } *p++ = ')'; if (uri) { p = stpcpy (p, "(uri %b)"); - assert (argidx+1 < DIM (args)); + log_assert (argidx+1 < DIM (args)); uri_intlen = (int)uri_length; args[argidx++] = (void *)&uri_intlen; args[argidx++] = (void *)&uri; @@ -1416,14 +1385,14 @@ agent_public_key_from_file (ctrl_t ctrl, if (comment) { p = stpcpy (p, "(comment %b)"); - assert (argidx+1 < DIM (args)); + log_assert (argidx+1 < DIM (args)); comment_intlen = (int)comment_length; args[argidx++] = (void *)&comment_intlen; args[argidx++] = (void*)&comment; } *p++ = ')'; *p = 0; - assert (argidx < DIM (args)); + log_assert (argidx < DIM (args)); args[argidx] = NULL; err = gcry_sexp_build_array (&list, NULL, format, args); @@ -1520,7 +1489,7 @@ agent_key_info_from_file (ctrl_t ctrl, const unsigned char *grip, if (!err) { n = gcry_sexp_canon_len (s, 0, NULL, NULL); - assert (n); + log_assert (n); *r_shadow_info = xtrymalloc (n); if (!*r_shadow_info) err = gpg_error_from_syserror (); |