add_ref(): verify that the refname is formatted correctly

In add_ref(), verify that the refname is formatted correctly before
adding it to the ref_list.  Here we have to allow refname components
that start with ".", since (for example) the remote protocol uses
synthetic reference name ".have".  So add a new REFNAME_DOT_COMPONENT
flag that can be passed to check_refname_format() to allow leading
dots.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index 096b42c5e993193dd83a02128be4b90ebc59edd1..832a52f7818369bca969d49317718714a5bcabac 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -56,6 +56,8 @@ static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
        entry = xmalloc(sizeof(struct ref_list) + len);
        hashcpy(entry->sha1, sha1);
        hashclr(entry->peeled);
+       if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
+               die("Reference has invalid format: '%s'", name);
        memcpy(entry->name, name, len);
        entry->flag = flag;
        entry->next = list;
@@ -900,7 +902,7 @@ static inline int bad_ref_char(int ch)
  * the length of the component found, or -1 if the component is not
  * legal.
  */
-static int check_refname_component(const char *ref)
+static int check_refname_component(const char *ref, int flags)
 {
        const char *cp;
        char last = '\0';
@@ -919,8 +921,16 @@ static int check_refname_component(const char *ref)
        }
        if (cp == ref)
                return -1; /* Component has zero length. */
-       if (ref[0] == '.')
-               return -1; /* Component starts with '.'. */
+       if (ref[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 (ref[1] == '\0')
+                       return -1; /* Component equals ".". */
+       }
        if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
                return -1; /* Refname ends with ".lock". */
        return cp - ref;
@@ -932,7 +942,7 @@ int check_refname_format(const char *ref, int flags)
 
        while (1) {
                /* We are at the start of a path component. */
-               component_len = check_refname_component(ref);
+               component_len = check_refname_component(ref, flags);
                if (component_len < 0) {
                        if ((flags & REFNAME_REFSPEC_PATTERN) &&
                                        ref[0] == '*' &&

diff --git a/refs.h b/refs.h
index b0da5fc95dff025a8dd5c1f299ee25efc6141e81..d5ac133336dc0da45cd916207d12a5e0e4237ae3 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -99,6 +99,7 @@ extern int for_each_reflog(each_ref_fn, void *);
 
 #define REFNAME_ALLOW_ONELEVEL 1
 #define REFNAME_REFSPEC_PATTERN 2
+#define REFNAME_DOT_COMPONENT 4
 
 /*
  * Return 0 iff ref has the correct format for a refname according to
@@ -106,7 +107,10 @@ extern int for_each_reflog(each_ref_fn, void *);
  * REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
  * reference names.  If REFNAME_REFSPEC_PATTERN is set in flags, then
  * allow a "*" wildcard character in place of one of the name
- * components.  No leading or repeated slashes are accepted.
+ * components.  No leading or repeated slashes are accepted.  If
+ * REFNAME_DOT_COMPONENT is set in flags, then allow refname
+ * components to start with "." (but not a whole component equal to
+ * "." or "..").
  */
 extern int check_refname_format(const char *ref, int flags);