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[PATCH] Prevent buffer overflows when path is too big

From
Antoine Pelisse <apelisse@gmail.com>
Date
Oct 19, 2013, 10:52 UTC
Message-ID
<1382179954-5169-1-git-send-email-apelisse@gmail.com>
In-Reply-To
<CABPQNSaqjKPGAQ4EKBSk+bQP2WMksc6M0YQxSkB91UrnFF28xQ@mail.gmail.com>

Currently, most buffers created with PATH_MAX length, are not checked when being written, and can overflow if PATH_MAX is not big enough to hold the path.

Fix that by using strlcpy() where strcpy() was used, and also run some extra checks when copy is done with memcpy().

Reported-by: Wataru Noguchi <wnoguchi.0727@gmail.com>
Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
---
 abspath.c        | 10 +++++++---
 diffcore-order.c |  2 +-
 entry.c          | 14 ++++++++++----
 unpack-trees.c   |  2 ++
 4 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/abspath.c b/abspath.c
index 64adbe2..0e60ba4 100644
--- a/abspath.c
+++ b/abspath.c
@@ -216,11 +216,15 @@ const char *absolute_path(const char *path)
 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
 {
 	static char path[PATH_MAX];
+
+	if (pfx_len > PATH_MAX)
+		die("Too long prefix path: %s", pfx);
+
 #ifndef GIT_WINDOWS_NATIVE
 	if (!pfx_len || is_absolute_path(arg))
 		return arg;
 	memcpy(path, pfx, pfx_len);
-	strcpy(path + pfx_len, arg);
+	strlcpy(path + pfx_len, arg, PATH_MAX - pfx_len);
 #else
 	char *p;
 	/* don't add prefix to absolute paths, but still replace '\' by '/' */
@@ -228,8 +232,8 @@ const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
 		pfx_len = 0;
 	else if (pfx_len)
 		memcpy(path, pfx, pfx_len);
-	strcpy(path + pfx_len, arg);
-	for (p = path + pfx_len; *p; p++)
+	strlcpy(path + pfx_len, arg, PATH_MAX - pfx_len);
+	for (p = path + pfx_len; p < path + PATH_MAX && *p; p++)
 		if (*p == '\\')
 			*p = '/';
 #endif
diff --git a/diffcore-order.c b/diffcore-order.c
index 23e9385..f083c82 100644
--- a/diffcore-order.c
+++ b/diffcore-order.c
@@ -76,7 +76,7 @@ static int match_order(const char *path)
 	char p[PATH_MAX];
 
 	for (i = 0; i < order_cnt; i++) {
-		strcpy(p, path);
+		strlcpy(p, path, PATH_MAX);
 		while (p[0]) {
 			char *cp;
 			if (!fnmatch(order[i], p, 0))
diff --git a/entry.c b/entry.c
index acc892f..39bee42 100644
--- a/entry.c
+++ b/entry.c
@@ -50,17 +50,20 @@ static void remove_subtree(const char *path)
 	struct dirent *de;
 	char pathbuf[PATH_MAX];
 	char *name;
+	size_t pathlen;
 
 	if (!dir)
 		die_errno("cannot opendir '%s'", path);
-	strcpy(pathbuf, path);
-	name = pathbuf + strlen(path);
+	strlcpy(pathbuf, path, PATH_MAX);
+	pathlen = strlen(path);
+	name = pathbuf + pathlen;
 	*name++ = '/';
+	pathlen++;
 	while ((de = readdir(dir)) != NULL) {
 		struct stat st;
 		if (is_dot_or_dotdot(de->d_name))
 			continue;
-		strcpy(name, de->d_name);
+		strlcpy(name, de->d_name, PATH_MAX - pathlen);
 		if (lstat(pathbuf, &st))
 			die_errno("cannot lstat '%s'", pathbuf);
 		if (S_ISDIR(st.st_mode))
@@ -244,8 +247,11 @@ int checkout_entry(struct cache_entry *ce,
 	if (topath)
 		return write_entry(ce, topath, state, 1);
 
+	if (len > PATH_MAX + 1)
+		die("Too long path: %s", state->base_dir);
+
 	memcpy(path, state->base_dir, len);
-	strcpy(path + len, ce->name);
+	strlcpy(path + len, ce->name, PATH_MAX + 1 - len);
 	len += ce_namelen(ce);
 
 	if (!check_path(path, len, &st, state->base_dir_len)) {
diff --git a/unpack-trees.c b/unpack-trees.c
index 1a61e6f..85473b1 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -918,6 +918,8 @@ static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 			int processed;
 
 			len = slash - name;
+			if (len + prefix_len >= PATH_MAX)
+				len = PATH_MAX - prefix_len - 1;
 			memcpy(prefix + prefix_len, name, len);
 
 			/*

-- 
1.8.4.1.507.g9768648.dirty

-- 
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Previous: Wataru NoguchiNext: Torsten Bögershausen
Message 13 of 44 in “mingw-multibyte: fix memory acces violation and path length limits.”
  1. mingw-multibyte: fix memory acces violation and path length limits.Wataru Noguchi, Sep 28, 2013
  2. Johannes SchindelinSep 28, 2013
  3. Wataru NoguchiSep 29, 2013
  4. Stefan BellerSep 29, 2013
  5. Wataru NoguchiOct 1, 2013
  6. René ScharfeSep 30, 2013
  7. Erik Faye-LundSep 30, 2013
  8. Wataru NoguchiOct 1, 2013
  9. Wataru NoguchiOct 2, 2013
  10. Antoine PelisseOct 3, 2013
  11. Erik Faye-LundOct 3, 2013
  12. Wataru NoguchiOct 5, 2013
  13. Prevent buffer overflows when path is too bigAntoine Pelisse, Oct 19, 2013
  14. Torsten BögershausenOct 20, 2013
  15. Ondřej BílkaOct 20, 2013
  16. Torsten BögershausenOct 20, 2013
  17. Ondřej BílkaOct 20, 2013
  18. Duy NguyenOct 20, 2013
  19. Antoine PelisseOct 20, 2013
  20. Duy NguyenOct 21, 2013
  21. Johannes SixtOct 21, 2013
  22. Erik Faye-LundOct 21, 2013
  23. Jeff KingOct 21, 2013
  24. Jeff KingOct 21, 2013
  25. 1/2 entry.c: convert checkout_entry to use strbufNguyễn Thái Ngọc Duy, Oct 23, 2013
  26. 2/2 entry.c: convert write_entry to use strbufNguyễn Thái Ngọc Duy, Oct 23, 2013
  27. Junio C HamanoOct 23, 2013
  28. Duy NguyenOct 24, 2013
  29. Junio C HamanoOct 24, 2013
  30. Duy NguyenOct 24, 2013
  31. Antoine PelisseOct 23, 2013
  32. Duy NguyenOct 23, 2013
  33. Antoine PelisseOct 23, 2013
  34. Jeff KingOct 23, 2013
  35. Erik Faye-LundOct 23, 2013
  36. Jeff KingOct 23, 2013
  37. Junio C HamanoOct 23, 2013
  38. Jeff KingOct 23, 2013
  39. entry.c: convert checkout_entry to use strbufNguyễn Thái Ngọc Duy, Oct 24, 2013
  40. Duy NguyenOct 23, 2013
  41. Prevent buffer overflows when path is too longAntoine Pelisse, Nov 26, 2013
  42. Junio C HamanoNov 26, 2013
  43. Antoine PelisseNov 29, 2013
  44. Prevent buffer overflows when path is too longAntoine Pelisse, Dec 14, 2013

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