[PATCH v7 2/5] setup: sanity check file size in read_gitfile_gently
- From
Erik Elfström <erik.elfstrom@gmail.com>
- Date
- Jun 9, 2015, 18:24 UTC
- Message-ID
- <1433874279-30720-3-git-send-email-erik.elfstrom@gmail.com>
- In-Reply-To
- <1433874279-30720-1-git-send-email-erik.elfstrom@gmail.com>
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@gmail.com> --- 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..e76955e 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) { + static const int one_MB = 1 << 20; 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 > one_MB) { + 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