Code

resolve_ref(): do not follow incorrectly-formatted symbolic refs
[git.git] / refs.c
diff --git a/refs.c b/refs.c
index 6f313a9e0cdec2400a993cf7c3dfa87529a493ae..b0555018995e5f029f3dd1d014e1ac9ef74c3672 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -451,7 +451,7 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
        memcpy(gitdir + len, "/.git", 6);
        len += 5;
 
-       tmp = read_gitfile_gently(gitdir);
+       tmp = read_gitfile(gitdir);
        if (tmp) {
                free(gitdir);
                len = strlen(tmp);
@@ -465,6 +465,23 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
        return retval;
 }
 
+/*
+ * Try to read ref from the packed references.  On success, set sha1
+ * and return 0; otherwise, return -1.
+ */
+static int get_packed_ref(const char *ref, unsigned char *sha1)
+{
+       struct ref_list *list = get_packed_refs(NULL);
+       while (list) {
+               if (!strcmp(ref, list->name)) {
+                       hashcpy(sha1, list->sha1);
+                       return 0;
+               }
+               list = list->next;
+       }
+       return -1;
+}
+
 /*
  * If the "reading" argument is set, this function finds out what _object_
  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
@@ -497,29 +514,36 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
                        return NULL;
 
                git_snpath(path, sizeof(path), "%s", ref);
-               /* Special case: non-existing file. */
+
                if (lstat(path, &st) < 0) {
-                       struct ref_list *list = get_packed_refs(NULL);
-                       while (list) {
-                               if (!strcmp(ref, list->name)) {
-                                       hashcpy(sha1, list->sha1);
-                                       if (flag)
-                                               *flag |= REF_ISPACKED;
-                                       return ref;
-                               }
-                               list = list->next;
+                       if (errno != ENOENT)
+                               return NULL;
+                       /*
+                        * The loose reference file does not exist;
+                        * check for a packed reference.
+                        */
+                       if (!get_packed_ref(ref, sha1)) {
+                               if (flag)
+                                       *flag |= REF_ISPACKED;
+                               return ref;
                        }
-                       if (reading || errno != ENOENT)
+                       /* The reference is not a packed reference, either. */
+                       if (reading) {
                                return NULL;
-                       hashclr(sha1);
-                       return ref;
+                       } else {
+                               hashclr(sha1);
+                               return ref;
+                       }
                }
 
                /* Follow "normalized" - ie "refs/.." symlinks by hand */
                if (S_ISLNK(st.st_mode)) {
                        len = readlink(path, buffer, sizeof(buffer)-1);
-                       if (len >= 5 && !memcmp("refs/", buffer, 5)) {
-                               buffer[len] = 0;
+                       if (len < 0)
+                               return NULL;
+                       buffer[len] = 0;
+                       if (!prefixcmp(buffer, "refs/") &&
+                                       !check_refname_format(buffer, 0)) {
                                strcpy(ref_buffer, buffer);
                                ref = ref_buffer;
                                if (flag)
@@ -543,25 +567,30 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
                        return NULL;
                len = read_in_full(fd, buffer, sizeof(buffer)-1);
                close(fd);
+               if (len < 0)
+                       return NULL;
+               while (len && isspace(buffer[len-1]))
+                       len--;
+               buffer[len] = '\0';
 
                /*
                 * Is it a symbolic ref?
                 */
-               if (len < 4 || memcmp("ref:", buffer, 4))
+               if (prefixcmp(buffer, "ref:"))
                        break;
                buf = buffer + 4;
-               len -= 4;
-               while (len && isspace(*buf))
-                       buf++, len--;
-               while (len && isspace(buf[len-1]))
-                       len--;
-               buf[len] = 0;
-               memcpy(ref_buffer, buf, len + 1);
-               ref = ref_buffer;
+               while (isspace(*buf))
+                       buf++;
+               if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
+                       warning("symbolic reference in %s is formatted incorrectly",
+                               path);
+                       return NULL;
+               }
+               ref = strcpy(ref_buffer, buf);
                if (flag)
                        *flag |= REF_ISSYMREF;
        }
-       if (len < 40 || get_sha1_hex(buffer, sha1))
+       if (get_sha1_hex(buffer, sha1))
                return NULL;
        return ref;
 }
@@ -860,70 +889,79 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
  * - it contains a "\" (backslash)
  */
 
+/* Return true iff ch is not allowed in reference names. */
 static inline int bad_ref_char(int ch)
 {
-       if (((unsigned) ch) <= ' ' ||
+       if (((unsigned) ch) <= ' ' || ch == 0x7f ||
            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
                return 1;
        /* 2.13 Pattern Matching Notation */
-       if (ch == '?' || ch == '[') /* Unsupported */
+       if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
                return 1;
-       if (ch == '*') /* Supported at the end */
-               return 2;
        return 0;
 }
 
-int check_ref_format(const char *ref)
+/*
+ * Try to read one refname component from the front of ref.  Return
+ * the length of the component found, or -1 if the component is not
+ * legal.
+ */
+static int check_refname_component(const char *ref)
 {
-       int ch, level, bad_type, last;
-       int ret = CHECK_REF_FORMAT_OK;
-       const char *cp = ref;
-
-       level = 0;
-       while (1) {
-               while ((ch = *cp++) == '/')
-                       ; /* tolerate duplicated slashes */
-               if (!ch)
-                       /* should not end with slashes */
-                       return CHECK_REF_FORMAT_ERROR;
-
-               /* we are at the beginning of the path component */
-               if (ch == '.')
-                       return CHECK_REF_FORMAT_ERROR;
-               bad_type = bad_ref_char(ch);
-               if (bad_type) {
-                       if (bad_type == 2 && (!*cp || *cp == '/') &&
-                           ret == CHECK_REF_FORMAT_OK)
-                               ret = CHECK_REF_FORMAT_WILDCARD;
-                       else
-                               return CHECK_REF_FORMAT_ERROR;
-               }
+       const char *cp;
+       char last = '\0';
 
+       for (cp = ref; ; cp++) {
+               char ch = *cp;
+               if (ch == '\0' || ch == '/')
+                       break;
+               if (bad_ref_char(ch))
+                       return -1; /* Illegal character in refname. */
+               if (last == '.' && ch == '.')
+                       return -1; /* Refname contains "..". */
+               if (last == '@' && ch == '{')
+                       return -1; /* Refname contains "@{". */
                last = ch;
-               /* scan the rest of the path component */
-               while ((ch = *cp++) != 0) {
-                       bad_type = bad_ref_char(ch);
-                       if (bad_type)
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (ch == '/')
-                               break;
-                       if (last == '.' && ch == '.')
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (last == '@' && ch == '{')
-                               return CHECK_REF_FORMAT_ERROR;
-                       last = ch;
-               }
-               level++;
-               if (!ch) {
-                       if (ref <= cp - 2 && cp[-2] == '.')
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (level < 2)
-                               return CHECK_REF_FORMAT_ONELEVEL;
-                       if (has_extension(ref, ".lock"))
-                               return CHECK_REF_FORMAT_ERROR;
-                       return ret;
+       }
+       if (cp == ref)
+               return -1; /* Component has zero length. */
+       if (ref[0] == '.')
+               return -1; /* Component starts with '.'. */
+       if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
+               return -1; /* Refname ends with ".lock". */
+       return cp - ref;
+}
+
+int check_refname_format(const char *ref, int flags)
+{
+       int component_len, component_count = 0;
+
+       while (1) {
+               /* We are at the start of a path component. */
+               component_len = check_refname_component(ref);
+               if (component_len < 0) {
+                       if ((flags & REFNAME_REFSPEC_PATTERN) &&
+                                       ref[0] == '*' &&
+                                       (ref[1] == '\0' || ref[1] == '/')) {
+                               /* Accept one wildcard as a full refname component. */
+                               flags &= ~REFNAME_REFSPEC_PATTERN;
+                               component_len = 1;
+                       } else {
+                               return -1;
+                       }
                }
+               component_count++;
+               if (ref[component_len] == '\0')
+                       break;
+               /* Skip to next component. */
+               ref += component_len + 1;
        }
+
+       if (ref[component_len - 1] == '.')
+               return -1; /* Refname ends with '.'. */
+       if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
+               return -1; /* Refname has only one component. */
+       return 0;
 }
 
 const char *prettify_refname(const char *name)
@@ -1106,7 +1144,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char
 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 {
        char refpath[PATH_MAX];
-       if (check_ref_format(ref))
+       if (check_refname_format(ref, 0))
                return NULL;
        strcpy(refpath, mkpath("refs/%s", ref));
        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
@@ -1114,13 +1152,9 @@ struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 
 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 {
-       switch (check_ref_format(ref)) {
-       default:
+       if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
                return NULL;
-       case 0:
-       case CHECK_REF_FORMAT_ONELEVEL:
-               return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
-       }
+       return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 }
 
 static struct lock_file packlock;