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[PATCH 8/8] Enable GIT_DEBUG_MEMCHECK on git_pathname()

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Nov 17, 2011, 09:32 UTC
Message-ID
<1321522335-24193-9-git-send-email-pclouds@gmail.com>
In-Reply-To
<1321522335-24193-1-git-send-email-pclouds@gmail.com>

Make git_pathname() use xmalloc_mmap/xfree_mmap to catch invalid access to old buffer when it's already overwritten.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache.h |   11 +++++++----
 path.c  |   28 +++++++++++++++++++---------
 2 files changed, 26 insertions(+), 13 deletions(-)
diff --git a/cache.h b/cache.h
index feb44a5..66365fb 100644
--- a/cache.h
+++ b/cache.h
@@ -661,10 +661,13 @@ extern char *git_pathdup(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
 
 /* Return a statically allocated filename matching the sha1 signature */
-extern char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
-extern char *git_path(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
-extern char *git_path_submodule(const char *path, const char *fmt, ...)
-	__attribute__((format (printf, 2, 3)));
+#define mkpath(...) mkpath_real(__FUNCTION__, __LINE__, __VA_ARGS__)
+extern char *mkpath_real(const char *file, int line, const char *fmt, ...) __attribute__((format (printf, 3, 4)));
+#define git_path( ...) git_path_real(__FUNCTION__, __LINE__, __VA_ARGS__)
+extern char *git_path_real(const char *file, int line, const char *fmt, ...) __attribute__((format (printf, 3, 4)));
+#define git_path_submodule(path, ...) git_path_submodule_real(__FUNCTION__, __LINE__, path, __VA_ARGS__)
+extern char *git_path_submodule_real(const char *file, int line, const char *path, const char *fmt, ...)
+	__attribute__((format (printf, 4, 5)));
 
 extern char *sha1_file_name(const unsigned char *sha1);
 extern char *sha1_pack_name(const unsigned char *sha1);
diff --git a/path.c b/path.c
index b6f71d1..d2aa941 100644
--- a/path.c
+++ b/path.c
@@ -15,11 +15,21 @@
 
 static char bad_path[] = "/bad-path/";
 
-static char *get_pathname(void)
+static char *get_pathname(const char *file, int line)
 {
-	static char pathname_array[4][PATH_MAX];
+	static char real_pathname_array[4][PATH_MAX];
+	static char *pathname_array[4];
 	static int index;
-	return pathname_array[3 & ++index];
+	int idx = 3 & ++index;
+
+	if (!pathname_array[idx] && !getenv("GIT_DEBUG_MEMCHECK"))
+		pathname_array[idx] = real_pathname_array[idx];
+
+	if (pathname_array[idx] != real_pathname_array[idx]) {
+		xfree_mmap(pathname_array[idx]);
+		pathname_array[idx] = xmalloc_mmap(PATH_MAX, file, line);
+	}
+	return pathname_array[idx];
 }
 
 static char *cleanup_path(char *path)
@@ -87,11 +97,11 @@ char *git_pathdup(const char *fmt, ...)
 	return xstrdup(path);
 }
 
-char *mkpath(const char *fmt, ...)
+char *mkpath_real(const char *file, int line, const char *fmt, ...)
 {
 	va_list args;
 	unsigned len;
-	char *pathname = get_pathname();
+	char *pathname = get_pathname(file, line);
 
 	va_start(args, fmt);
 	len = vsnprintf(pathname, PATH_MAX, fmt, args);
@@ -101,10 +111,10 @@ char *mkpath(const char *fmt, ...)
 	return cleanup_path(pathname);
 }
 
-char *git_path(const char *fmt, ...)
+char *git_path_real(const char *file, int line, const char *fmt, ...)
 {
 	const char *git_dir = get_git_dir();
-	char *pathname = get_pathname();
+	char *pathname = get_pathname(file, line);
 	va_list args;
 	unsigned len;
 
@@ -122,9 +132,9 @@ char *git_path(const char *fmt, ...)
 	return cleanup_path(pathname);
 }
 
-char *git_path_submodule(const char *path, const char *fmt, ...)
+char *git_path_submodule_real(const char *file, int line, const char *path, const char *fmt, ...)
 {
-	char *pathname = get_pathname();
+	char *pathname = get_pathname(file, line);
 	struct strbuf buf = STRBUF_INIT;
 	const char *git_dir;
 	va_list args;
-- 
1.7.4.74.g639db
Previous: Nguyễn Thái Ngọc DuyNext: Ramkumar Ramachandra
Message 13 of 27 in “nd/resolve-ref v2”
  1. 0/8 nd/resolve-ref v2Nguyễn Thái Ngọc Duy, Nov 17, 2011
  2. 1/8 Convert many resolve_ref() calls to read_ref*() and ref_exists()Nguyễn Thái Ngọc Duy, Nov 17, 2011
  3. 2/8 Rename resolve_ref() to resolve_ref_unsafe()Nguyễn Thái Ngọc Duy, Nov 17, 2011
  4. 3/8 Re-add resolve_ref() that always returns an allocated bufferNguyễn Thái Ngọc Duy, Nov 17, 2011
  5. 4/8 cmd_merge: convert to single exit pointNguyễn Thái Ngọc Duy, Nov 17, 2011
  6. Ramkumar RamachandraNov 17, 2011
  7. Jonathan NiederNov 17, 2011
  8. 5/8 Use resolve_ref() instead of resolve_ref_unsafe()Nguyễn Thái Ngọc Duy, Nov 17, 2011
  9. 6/8 Convert resolve_ref_unsafe+xstrdup to resolve_refNguyễn Thái Ngọc Duy, Nov 17, 2011
  10. Ramkumar RamachandraNov 17, 2011
  11. Nguyen Thai Ngoc DuyNov 18, 2011
  12. 7/8 Guard memory overwriting in resolve_ref_unsafe's static bufferNguyễn Thái Ngọc Duy, Nov 17, 2011
  13. 8/8 Enable GIT_DEBUG_MEMCHECK on git_pathname()Nguyễn Thái Ngọc Duy, Nov 17, 2011
  14. Ramkumar RamachandraNov 17, 2011
  15. Jeff KingNov 17, 2011
  16. Nguyen Thai Ngoc DuyNov 18, 2011
  17. Jeff KingNov 18, 2011
  18. Jonathan NiederNov 18, 2011
  19. Nguyen Thai Ngoc DuyNov 18, 2011
  20. Jeff KingNov 18, 2011
  21. Jonathan NiederNov 18, 2011
  22. Johan HerlandNov 18, 2011
  23. Jonathan NiederNov 18, 2011
  24. Junio C HamanoNov 18, 2011
  25. Bernhard R. LinkNov 18, 2011
  26. Jonathan NiederNov 17, 2011
  27. Nguyen Thai Ngoc DuyDec 6, 2011

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