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authorJohn Keeping <john@keeping.me.uk>2013-04-01 19:03:34 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2013-04-08 15:59:46 +0200
commitb1f17f168b91d709c0c0e62608de301a36f06da9 (patch)
tree9aff1fe903087cb5016ab2afdb32a7ca1cc139b2
parent4b4a62d507adc61e20e75e2748301ef307a6c95f (diff)
Fix out-of-bounds memory accesses with virtual_root=""
The CGit configuration variable virtual_root is normalized so that it does not have a trailing '/' character, but it is allowed to be empty (the empty string and NULL have different meanings here) and there is code that is insufficiently cautious when checking if it ends in a '/': if (virtual_root[strlen(virtual_root) - 1] != '/') Clearly this check is redundant, but rather than simply removing it we get a slight efficiency improvement by switching the normalization so that the virtual_root variable always ends in '/'. Do this with a new "ensure_end" helper. Signed-off-by: John Keeping <john@keeping.me.uk>
-rw-r--r--cgit.c11
-rw-r--r--cgit.h3
-rw-r--r--shared.c15
-rw-r--r--ui-shared.c14
4 files changed, 25 insertions, 18 deletions
diff --git a/cgit.c b/cgit.c
index ca3034c..6f75db1 100644
--- a/cgit.c
+++ b/cgit.c
@@ -155,9 +155,7 @@ static void config_cb(const char *name, const char *value)
else if (!strcmp(name, "strict-export"))
ctx.cfg.strict_export = xstrdup(value);
else if (!strcmp(name, "virtual-root")) {
- ctx.cfg.virtual_root = trim_end(value, '/');
- if (!ctx.cfg.virtual_root && (!strcmp(value, "/")))
- ctx.cfg.virtual_root = "";
+ ctx.cfg.virtual_root = ensure_end(value, '/');
} else if (!strcmp(name, "nocache"))
ctx.cfg.nocache = atoi(value);
else if (!strcmp(name, "noplainemail"))
@@ -833,11 +831,8 @@ int main(int argc, const char **argv)
* that virtual-root equals SCRIPT_NAME, minus any possibly
* trailing slashes.
*/
- if (!ctx.cfg.virtual_root && ctx.cfg.script_name) {
- ctx.cfg.virtual_root = trim_end(ctx.cfg.script_name, '/');
- if (!ctx.cfg.virtual_root)
- ctx.cfg.virtual_root = "";
- }
+ if (!ctx.cfg.virtual_root && ctx.cfg.script_name)
+ ctx.cfg.virtual_root = ensure_end(ctx.cfg.script_name, '/');
/* If no url parameter is specified on the querystring, lets
* use PATH_INFO as url. This allows cgit to work with virtual
diff --git a/cgit.h b/cgit.h
index 081f669..fc3fc6f 100644
--- a/cgit.h
+++ b/cgit.h
@@ -190,7 +190,7 @@ struct cgit_config {
char *script_name;
char *section;
char *repository_sort;
- char *virtual_root;
+ char *virtual_root; /* Always ends with '/'. */
char *strict_export;
int cache_size;
int cache_dynamic_ttl;
@@ -300,6 +300,7 @@ extern int chk_positive(int result, char *msg);
extern int chk_non_negative(int result, char *msg);
extern char *trim_end(const char *str, char c);
+extern char *ensure_end(const char *str, char c);
extern char *strlpart(char *txt, int maxlen);
extern char *strrpart(char *txt, int maxlen);
diff --git a/shared.c b/shared.c
index cc06930..1fa9c99 100644
--- a/shared.c
+++ b/shared.c
@@ -115,6 +115,21 @@ char *trim_end(const char *str, char c)
return xstrndup(str, len);
}
+char *ensure_end(const char *str, char c)
+{
+ size_t len = strlen(str);
+ char *result;
+
+ if (len && str[len - 1] == c)
+ return xstrndup(str, len);
+
+ result = xmalloc(len + 2);
+ memcpy(result, str, len);
+ result[len] = '/';
+ result[len + 1] = '\0';
+ return result;
+}
+
char *strlpart(char *txt, int maxlen)
{
char *result;
diff --git a/ui-shared.c b/ui-shared.c
index 945d560..c1f3c20 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -57,7 +57,7 @@ const char *cgit_hosturl()
const char *cgit_rooturl()
{
if (ctx.cfg.virtual_root)
- return fmt("%s/", ctx.cfg.virtual_root);
+ return ctx.cfg.virtual_root;
else
return ctx.cfg.script_name;
}
@@ -65,7 +65,7 @@ const char *cgit_rooturl()
char *cgit_repourl(const char *reponame)
{
if (ctx.cfg.virtual_root) {
- return fmt("%s/%s/", ctx.cfg.virtual_root, reponame);
+ return fmt("%s%s/", ctx.cfg.virtual_root, reponame);
} else {
return fmt("?r=%s", reponame);
}
@@ -78,7 +78,7 @@ char *cgit_fileurl(const char *reponame, const char *pagename,
char *delim;
if (ctx.cfg.virtual_root) {
- tmp = fmt("%s/%s/%s/%s", ctx.cfg.virtual_root, reponame,
+ tmp = fmt("%s%s/%s/%s", ctx.cfg.virtual_root, reponame,
pagename, (filename ? filename:""));
delim = "?";
} else {
@@ -126,11 +126,9 @@ static void site_url(const char *page, const char *search, const char *sort, int
{
char *delim = "?";
- if (ctx.cfg.virtual_root) {
+ if (ctx.cfg.virtual_root)
html_attr(ctx.cfg.virtual_root);
- if (ctx.cfg.virtual_root[strlen(ctx.cfg.virtual_root) - 1] != '/')
- html("/");
- } else
+ else
html(ctx.cfg.script_name);
if (page) {
@@ -201,8 +199,6 @@ static char *repolink(const char *title, const char *class, const char *page,
html(" href='");
if (ctx.cfg.virtual_root) {
html_url_path(ctx.cfg.virtual_root);
- if (ctx.cfg.virtual_root[strlen(ctx.cfg.virtual_root) - 1] != '/')
- html("/");
html_url_path(ctx.repo->url);
if (ctx.repo->url[strlen(ctx.repo->url) - 1] != '/')
html("/");