read_gitfile_gently will allocate a buffer to fit the entire file that
should be read. Add a sanity check of the file size before opening to
avoid allocating a potentially huge amount of memory if we come across
a large file that someone happened to name ".git". The limit is set to
a sufficiently unreasonable size that should never be exceeded by a
genuine .git file.
Signed-off-by: Erik Elfström <erik.elfstrom@xxxxxxxxx>
---
cache.h | 1 +
setup.c | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/cache.h b/cache.h
index 25578cb..858d9b3 100644
--- a/cache.h
+++ b/cache.h
@@ -454,6 +454,7 @@ extern const char *get_git_work_tree(void);
#define READ_GITFILE_ERR_INVALID_FORMAT 5
#define READ_GITFILE_ERR_NO_PATH 6
#define READ_GITFILE_ERR_NOT_A_REPO 7
+#define READ_GITFILE_ERR_TOO_LARGE 8
extern const char *read_gitfile_gently(const char *path, int *return_error_code);
#define read_gitfile(path) read_gitfile_gently((path), NULL)
extern const char *resolve_gitdir(const char *suspect);
diff --git a/setup.c b/setup.c
index 4748b63..a03ca94 100644
--- a/setup.c
+++ b/setup.c
@@ -414,6 +414,7 @@ static void update_linked_gitdir(const char *gitfile, const char *gitdir)
*/
const char *read_gitfile_gently(const char *path, int *return_error_code)
{
+ const int max_file_size = 1 << 20; /* 1MB */
int error_code = 0;
char *buf = NULL;
char *dir = NULL;
@@ -430,6 +431,10 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
error_code = READ_GITFILE_ERR_NOT_A_FILE;
goto cleanup_return;
}
+ if (st.st_size > max_file_size) {
+ error_code = READ_GITFILE_ERR_TOO_LARGE;
+ goto cleanup_return;
+ }
fd = open(path, O_RDONLY);
if (fd < 0) {
error_code = READ_GITFILE_ERR_OPEN_FAILED;
@@ -489,6 +494,8 @@ cleanup_return:
return NULL;
case READ_GITFILE_ERR_OPEN_FAILED:
die_errno("Error opening '%s'", path);
+ case READ_GITFILE_ERR_TOO_LARGE:
+ die("Too large to be a .git file: '%s'", path);
case READ_GITFILE_ERR_READ_FAILED:
die("Error reading %s", path);
case READ_GITFILE_ERR_INVALID_FORMAT:
--
2.4.3.373.gc496bfb.dirty
--
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