transport: simplify duplicating a substring in transport_get() using xmemdupz()
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index f8d59ab7f004a336b92dd2355ef4a518cef3231a..5ff457ebfce7aba9cd470f3e2e1f3f5dbe9d9741 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -70,16 +70,8 @@ static int check_refname_component(const char *refname, int flags)
 out:
        if (cp == refname)
                return 0; /* Component has zero length. */
-       if (refname[0] == '.') {
-               if (!(flags & REFNAME_DOT_COMPONENT))
-                       return -1; /* Component starts with '.'. */
-               /*
-                * Even if leading dots are allowed, don't allow "."
-                * as a component (".." is prevented by a rule above).
-                */
-               if (refname[1] == '\0')
-                       return -1; /* Component equals ".". */
-       }
+       if (refname[0] == '.')
+               return -1; /* Component starts with '.'. */
        if (cp - refname >= LOCK_SUFFIX_LEN &&
            !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
                return -1; /* Refname ends with ".lock". */
@@ -195,8 +187,8 @@ struct ref_dir {
 
 /*
  * Bit values for ref_entry::flag.  REF_ISSYMREF=0x01,
- * REF_ISPACKED=0x02, and REF_ISBROKEN=0x04 are public values; see
- * refs.h.
+ * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
+ * public values; see refs.h.
  */
 
 /*
@@ -204,16 +196,16 @@ struct ref_dir {
  * the correct peeled value for the reference, which might be
  * null_sha1 if the reference is not a tag or if it is broken.
  */
-#define REF_KNOWS_PEELED 0x08
+#define REF_KNOWS_PEELED 0x10
 
 /* ref_entry represents a directory of references */
-#define REF_DIR 0x10
+#define REF_DIR 0x20
 
 /*
  * Entry has not yet been read from disk (used only for REF_DIR
  * entries representing loose references)
  */
-#define REF_INCOMPLETE 0x20
+#define REF_INCOMPLETE 0x40
 
 /*
  * A ref_entry represents either a reference or a "subdirectory" of
@@ -282,6 +274,39 @@ static struct ref_dir *get_ref_dir(struct ref_entry *entry)
        return dir;
 }
 
+/*
+ * Check if a refname is safe.
+ * For refs that start with "refs/" we consider it safe as long they do
+ * not try to resolve to outside of refs/.
+ *
+ * For all other refs we only consider them safe iff they only contain
+ * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
+ * "config").
+ */
+static int refname_is_safe(const char *refname)
+{
+       if (starts_with(refname, "refs/")) {
+               char *buf;
+               int result;
+
+               buf = xmalloc(strlen(refname) + 1);
+               /*
+                * Does the refname try to escape refs/?
+                * For example: refs/foo/../bar is safe but refs/foo/../../bar
+                * is not.
+                */
+               result = !normalize_path_copy(buf, refname + strlen("refs/"));
+               free(buf);
+               return result;
+       }
+       while (*refname) {
+               if (!isupper(*refname) && *refname != '_')
+                       return 0;
+               refname++;
+       }
+       return 1;
+}
+
 static struct ref_entry *create_ref_entry(const char *refname,
                                          const unsigned char *sha1, int flag,
                                          int check_name)
@@ -290,8 +315,10 @@ static struct ref_entry *create_ref_entry(const char *refname,
        struct ref_entry *ref;
 
        if (check_name &&
-           check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
+           check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
                die("Reference has invalid format: '%s'", refname);
+       if (!check_name && !refname_is_safe(refname))
+               die("Reference has invalid name: '%s'", refname);
        len = strlen(refname) + 1;
        ref = xmalloc(sizeof(struct ref_entry) + len);
        hashcpy(ref->u.value.sha1, sha1);
@@ -1119,7 +1146,13 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 
                refname = parse_ref_line(refline, sha1);
                if (refname) {
-                       last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
+                       int flag = REF_ISPACKED;
+
+                       if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+                               hashclr(sha1);
+                               flag |= REF_BAD_NAME | REF_ISBROKEN;
+                       }
+                       last = create_ref_entry(refname, sha1, flag, 0);
                        if (peeled == PEELED_FULLY ||
                            (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
                                last->flag |= REF_KNOWS_PEELED;
@@ -1257,8 +1290,13 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
                                hashclr(sha1);
                                flag |= REF_ISBROKEN;
                        }
+                       if (check_refname_format(refname.buf,
+                                                REFNAME_ALLOW_ONELEVEL)) {
+                               hashclr(sha1);
+                               flag |= REF_BAD_NAME | REF_ISBROKEN;
+                       }
                        add_entry_to_dir(dir,
-                                        create_ref_entry(refname.buf, sha1, flag, 1));
+                                        create_ref_entry(refname.buf, sha1, flag, 0));
                }
                strbuf_setlen(&refname, dirnamelen);
        }
@@ -1377,10 +1415,10 @@ static struct ref_entry *get_packed_ref(const char *refname)
  * A loose ref file doesn't exist; check for a packed ref.  The
  * options are forwarded from resolve_safe_unsafe().
  */
-static const char *handle_missing_loose_ref(const char *refname,
-                                           int resolve_flags,
-                                           unsigned char *sha1,
-                                           int *flags)
+static int resolve_missing_loose_ref(const char *refname,
+                                    int resolve_flags,
+                                    unsigned char *sha1,
+                                    int *flags)
 {
        struct ref_entry *entry;
 
@@ -1393,14 +1431,15 @@ static const char *handle_missing_loose_ref(const char *refname,
                hashcpy(sha1, entry->u.value.sha1);
                if (flags)
                        *flags |= REF_ISPACKED;
-               return refname;
+               return 0;
        }
        /* The reference is not a packed reference, either. */
        if (resolve_flags & RESOLVE_REF_READING) {
-               return NULL;
+               errno = ENOENT;
+               return -1;
        } else {
                hashclr(sha1);
-               return refname;
+               return 0;
        }
 }
 
@@ -1411,13 +1450,29 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
        ssize_t len;
        char buffer[256];
        static char refname_buffer[256];
+       int bad_name = 0;
 
        if (flags)
                *flags = 0;
 
        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-               errno = EINVAL;
-               return NULL;
+               if (flags)
+                       *flags |= REF_BAD_NAME;
+
+               if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
+                   !refname_is_safe(refname)) {
+                       errno = EINVAL;
+                       return NULL;
+               }
+               /*
+                * dwim_ref() uses REF_ISBROKEN to distinguish between
+                * missing refs and refs that were present but invalid,
+                * to complain about the latter to stderr.
+                *
+                * We don't know whether the ref exists, so don't set
+                * REF_ISBROKEN yet.
+                */
+               bad_name = 1;
        }
        for (;;) {
                char path[PATH_MAX];
@@ -1443,11 +1498,17 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
                 */
        stat_ref:
                if (lstat(path, &st) < 0) {
-                       if (errno == ENOENT)
-                               return handle_missing_loose_ref(refname,
-                                               resolve_flags, sha1, flags);
-                       else
+                       if (errno != ENOENT)
                                return NULL;
+                       if (resolve_missing_loose_ref(refname, resolve_flags,
+                                                     sha1, flags))
+                               return NULL;
+                       if (bad_name) {
+                               hashclr(sha1);
+                               if (flags)
+                                       *flags |= REF_ISBROKEN;
+                       }
+                       return refname;
                }
 
                /* Follow "normalized" - ie "refs/.." symlinks by hand */
@@ -1467,6 +1528,10 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
                                refname = refname_buffer;
                                if (flags)
                                        *flags |= REF_ISSYMREF;
+                               if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
+                                       hashclr(sha1);
+                                       return refname;
+                               }
                                continue;
                        }
                }
@@ -1516,6 +1581,11 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
                                errno = EINVAL;
                                return NULL;
                        }
+                       if (bad_name) {
+                               hashclr(sha1);
+                               if (flags)
+                                       *flags |= REF_ISBROKEN;
+                       }
                        return refname;
                }
                if (flags)
@@ -1523,13 +1593,22 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
                buf = buffer + 4;
                while (isspace(*buf))
                        buf++;
+               refname = strcpy(refname_buffer, buf);
+               if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
+                       hashclr(sha1);
+                       return refname;
+               }
                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
                        if (flags)
                                *flags |= REF_ISBROKEN;
-                       errno = EINVAL;
-                       return NULL;
+
+                       if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
+                           !refname_is_safe(buf)) {
+                               errno = EINVAL;
+                               return NULL;
+                       }
+                       bad_name = 1;
                }
-               refname = strcpy(refname_buffer, buf);
        }
 }
 
@@ -2160,16 +2239,16 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
        int missing = 0;
        int attempts_remaining = 3;
 
-       if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-               errno = EINVAL;
-               return NULL;
-       }
-
        lock = xcalloc(1, sizeof(struct ref_lock));
        lock->lock_fd = -1;
 
        if (mustexist)
                resolve_flags |= RESOLVE_REF_READING;
+       if (flags & REF_DELETING) {
+               resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
+               if (flags & REF_NODEREF)
+                       resolve_flags |= RESOLVE_REF_NO_RECURSE;
+       }
 
        refname = resolve_ref_unsafe(refname, resolve_flags,
                                     lock->old_sha1, &type);
@@ -2567,6 +2646,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
        struct string_list_item *ref_to_delete;
        int i, ret, removed = 0;
 
+       assert(err);
+
        /* Look for a packed ref */
        for (i = 0; i < n; i++)
                if (get_packed_ref(refnames[i]))
@@ -2577,13 +2658,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
                return 0; /* no refname exists in packed refs */
 
        if (lock_packed_refs(0)) {
-               if (err) {
-                       unable_to_lock_message(git_path("packed-refs"), errno,
-                                              err);
-                       return -1;
-               }
-               unable_to_lock_error(git_path("packed-refs"), errno);
-               return error("cannot delete '%s' from packed refs", refnames[i]);
+               unable_to_lock_message(git_path("packed-refs"), errno, err);
+               return -1;
        }
        packed = get_packed_refs(&ref_cache);
 
@@ -2609,7 +2685,7 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
        /* Write what remains */
        ret = commit_packed_refs();
-       if (ret && err)
+       if (ret)
                strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
                            strerror(errno));
        return ret;
@@ -2617,6 +2693,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 {
+       assert(err);
+
        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
                /*
                 * loose.  The loose file name is the same as the
@@ -2884,10 +2962,10 @@ int log_ref_setup(const char *refname, char *logfile, int bufsize)
 
        logfd = open(logfile, oflags, 0666);
        if (logfd < 0) {
-               if (!(oflags & O_CREAT) && errno == ENOENT)
+               if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
                        return 0;
 
-               if ((oflags & O_CREAT) && errno == EISDIR) {
+               if (errno == EISDIR) {
                        if (remove_empty_directories(logfile)) {
                                int save_errno = errno;
                                error("There are still logs under '%s'",
@@ -3472,6 +3550,8 @@ struct ref_transaction {
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
+       assert(err);
+
        return xcalloc(1, sizeof(struct ref_transaction));
 }
 
@@ -3511,12 +3591,21 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: update called for transaction that is not open");
 
        if (have_old && !old_sha1)
                die("BUG: have_old is true but old_sha1 is NULL");
 
+       if (!is_null_sha1(new_sha1) &&
+           check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+               strbuf_addf(err, "refusing to update ref with bad name %s",
+                           refname);
+               return -1;
+       }
+
        update = add_update(transaction, refname);
        hashcpy(update->new_sha1, new_sha1);
        update->flags = flags;
@@ -3536,12 +3625,20 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: create called for transaction that is not open");
 
        if (!new_sha1 || is_null_sha1(new_sha1))
                die("BUG: create ref with null new_sha1");
 
+       if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+               strbuf_addf(err, "refusing to create ref with bad name %s",
+                           refname);
+               return -1;
+       }
+
        update = add_update(transaction, refname);
 
        hashcpy(update->new_sha1, new_sha1);
@@ -3561,6 +3658,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: delete called for transaction that is not open");
 
@@ -3623,13 +3722,14 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
                                        struct strbuf *err)
 {
        int i;
+
+       assert(err);
+
        for (i = 1; i < n; i++)
                if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
-                       const char *str =
-                               "Multiple updates for ref '%s' not allowed.";
-                       if (err)
-                               strbuf_addf(err, str, updates[i]->refname);
-
+                       strbuf_addf(err,
+                                   "Multiple updates for ref '%s' not allowed.",
+                                   updates[i]->refname);
                        return 1;
                }
        return 0;
@@ -3643,6 +3743,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        int n = transaction->nr;
        struct ref_update **updates = transaction->updates;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: commit called for transaction that is not open");
 
@@ -3664,21 +3766,23 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        /* Acquire all locks while verifying old values */
        for (i = 0; i < n; i++) {
                struct ref_update *update = updates[i];
+               int flags = update->flags;
 
+               if (is_null_sha1(update->new_sha1))
+                       flags |= REF_DELETING;
                update->lock = lock_ref_sha1_basic(update->refname,
                                                   (update->have_old ?
                                                    update->old_sha1 :
                                                    NULL),
                                                   NULL,
-                                                  update->flags,
+                                                  flags,
                                                   &update->type);
                if (!update->lock) {
                        ret = (errno == ENOTDIR)
                                ? TRANSACTION_NAME_CONFLICT
                                : TRANSACTION_GENERIC_ERROR;
-                       if (err)
-                               strbuf_addf(err, "Cannot lock the ref '%s'.",
-                                           update->refname);
+                       strbuf_addf(err, "Cannot lock the ref '%s'.",
+                                   update->refname);
                        goto cleanup;
                }
        }
@@ -3691,9 +3795,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                        if (write_ref_sha1(update->lock, update->new_sha1,
                                           update->msg)) {
                                update->lock = NULL; /* freed by write_ref_sha1 */
-                               if (err)
-                                       strbuf_addf(err, "Cannot update the ref '%s'.",
-                                                   update->refname);
+                               strbuf_addf(err, "Cannot update the ref '%s'.",
+                                           update->refname);
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }
@@ -3706,16 +3809,20 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (update->lock) {
-                       if (delete_ref_loose(update->lock, update->type, err))
+                       if (delete_ref_loose(update->lock, update->type, err)) {
                                ret = TRANSACTION_GENERIC_ERROR;
+                               goto cleanup;
+                       }
 
                        if (!(update->flags & REF_ISPRUNING))
                                delnames[delnum++] = update->lock->ref_name;
                }
        }
 
-       if (repack_without_refs(delnames, delnum, err))
+       if (repack_without_refs(delnames, delnum, err)) {
                ret = TRANSACTION_GENERIC_ERROR;
+               goto cleanup;
+       }
        for (i = 0; i < delnum; i++)
                unlink_or_warn(git_path("logs/%s", delnames[i]));
        clear_loose_ref_cache(&ref_cache);